Disorders in Dark Skin 34 Moetaz El-Domyati and Noha H. Moftah

The nail unit is a skin appendage produced by the skin. Its painful result, occasionally, with pus-filled small major function is mechanical protection of the distal digit, abscesses. Chronic paronychia may be painful and show peri- also representing a part of the overall cosmetic appearance of odic flare-ups in labor workers, after exposure to chemicals the body. Genetic disorders, infections, various dermatoses, and other irritants, etc. Treatment is by warm soaks with senility, tumors, etc. may result in a series of changes of the water, liquid antibacterial soaps, and topical antibiotics; in nail showing alterations of growth, color, thickness, and con- severe cases oral antibiotics may be required. If a paronychial tour of the nail plate. Thus, examination of the digits and abscess is diagnosed, surgical drainage is indicated [2]. nails often provides diagnostic clues for underlying cutane- ous or systemic disease. Alterations and deformities of the nails may be characteristic and helpful for the physician to 34.1.2 Fungal Infections support his diagnosis; others are not specific but still provide valuable clues for targeted medical investigation. Major dif- Infection of the nails with dermatophytes, Tinea (T.) ferences of nail pathology between Caucasians and dark-­ unguium is common both in white Caucasians and in pop- skinned ethnic populations are not known or prominent; ulations with darkly pigmented skin. The average preva- however, environmental exposure and socioeconomic cir- lence in fair skin populations in Europe and North America cumstances in populations living in hot climate zones differ is approximately 4% [3, 4] and up to 5.5–10% in popula- and cause differences in the clinical presentation and medi- tions with dark skin [5]. The prevalence of cal assistance. In addition, pigment lability in dark skin eas- is clearly higher (>10%) in patients with diabetes, distur- ily causes diffuse or striate [1]. bances of blood circulation, peripheral neuropathies, immunocompromised individuals, and the elderly. In pop- ulations with dark skin, onychomycosis represents 20–40% 34.1 Infections of the Nail of all onychopathies and about 30% of cutaneous fungal infections [5]. Tinea unguium represents 7.7% of all der- 34.1.1 Bacterial and Viral Infections matophyte infections [6], whereby T. interdigitale, T. rubrum, and T. verrucosum are the most common agents Nail infections are usually due to bacteria that invade dam- [7]. Rarely, T. soudanense may be detected. aged nails through the seal between the nail plate and the sur- The clinical picture includes: rounding tissue and enter and cause in the hyponychium and swelling of the surrounding nail folds (par- (a) Distal and lateral subungual onychomycosis (DLSO) onychia). The most common causative agents are which is the commonest pattern of fungal nail infection Staphylococcus spp., followed by pseudomonas and some in most populations (Fig. 34.1a) streptococci; in rare cases herpes viruses may be the causative (b) White superficial onychomycosis (WSO) seen primarily agent. In advanced cases discoloration of the nail plate and on the toes, in which fungi invade the nail plate surface, with formation of small, well-delineated, opaque, white, powder-like, transverse coalescing islands (c) Proximal subungual onychomycosis (PSO) which is the M. El-Domyati (*) • N. H. Moftah Department of Dermatology, STDs and Andrology, least common pattern, could be considered as the pre- Minia University, Al-Minya, Egypt senting sign of acquired immunodeficiency syndrome

© Springer International Publishing AG, part of Springer Nature 2018 369 C. E. Orfanos et al. (eds.), Pigmented Ethnic Skin and Imported Dermatoses, https://doi.org/10.1007/978-3-319-69422-1_34 370 M. El-Domyati and N. H. Moftah

Fig. 34.1 (a) Distal subungual onychomycosis a with distal and subungual hyperkeratosis. (b) Total dystrophic onychomycosis with thickened, rough, friable, and hyperkeratotic nail plates. (c) Candidal onychomycosis with swollen proximal nail folds, loss of cuticle, patent proximal nail groove, and total dystrophic nails

b

c

(d) Total dystrophic onychomycosis (TDO) occurs as the known as Beau’s lines. In candidal onychomycosis, there is result of progression of any of the three previous forms no subungual hyperkeratosis, and the nail does not crumble of onychomycosis with nail matrix involvement with away as in TDO [5, 8] (Fig. 34.1c). rough, friable, hyperkeratotic, and crumbling nails Infections with non-dermatophytic molds account for (Fig. 34.1b) 1.5–6% of all onychomycoses that fall into two categories, causative agents which are isolated from affected nails, in Infections with Candida spp. commonly occur in hot cli- particular Scytalidium dimidiatum and Scytalidium hyali- mate zones and fingernails of females due to frequent han- num, or opportunistic fungi that may be isolated as contami- dling of water and soap during household work leading to nants, e.g., Scopulariopsis brevicaulis and Aspergillus rough, irregular, convex, and dystrophic nails with loss of sydowii [8]. In tropical zones with moist environment, cuticle and proximal nail groove. Candida albicans can Scytalidium is often detected. infect the nail as a primary or secondary pathogen (18–20%); Diagnosis of onychomycosis is primarily based upon however, secondary appearance is more common, especially direct microscopy after scraping of hyperkeratotic nail bed after nail onycholysis and candidal paronychia. Nail matrix and mounting in 10–30% KOH with warming to emulsify infection results in transverse depressions in the nail plate lipids or adding 36% dimethyl sulfoxide instead of heating. 34 Nail Disorders in Dark Skin 371

Table 34.1 Commonly prescribed medications for onychomycosis

Dosing Cure rate (%) Treatment Indications Active agent schedule Clinical Mycotic Organism Adverse effects Comments Topical – WSO Ciclopirox 8% Daily for 6–9 29–36 (77% DF, NDM, – Periungual – Patients should not – Mild DLSO lacquer 48 weeks with yeasts erythema bathe for 8 h when – <50% of nail debridement) applied surface Amorolfine 5% Weekly for 1 16 DF, NDM, – Periungual – Damaged nail – <3 fingers lacquer 48 weeks yeasts erythema should be removed – No matrix – Discoloration using scissors or nail involvement Terbinafine Daily for 1 16 DF, NDM, clippers solution 48 weeks yeasts – Application to nail plate, nail bed, and Efinaconazole Daily for 16–17 53–55 DF, NDM, – Local reaction hyponychium 10% solution 48 weeks yeasts Tavaborole 5% Daily for 7–9 31–36 DF, NDM, solution 48 weeks yeasts Systemic – PSO Terbinafine 250 mg 1×/ 66 76 DF, NDM – GIT – Liver and renal – >50% of nail day disturbances function tests are surface – Asymptomatic required – >3 fingers liver enzyme elevation Itraconazole Pulse: 70 63 DF, NDM, – GIT – Liver function 200 mg 2×/ yeasts disturbances tests are required day for – Hypokalemia especially with 1 week/month – Elevated preexisting hepatic Continuous: 70 69 transaminase and dysfunction 200 mg 1×/ triglycerides – Contraindicated day in patients with ventricular dysfunction or congestive heart failure Fluconazole 150–300 mg 41 48 Candida, – GIT – Liver function 1×/week limited in disturbances tests and potassium DF levels are required – Not FDA-approved in onychomycosis Surgical Partial in: 0 – Infection debride- – Lateral nail – Distal nail ment involvement embedding – Onycholytic pocket on nail undersurface WSO white superficial onychomycosis, DLSO distal lateral subungual onychomycosis, PSO proximal superficial onychomycosis; DF dermatophytes; NDM non-dermatophytic molds; GIT gastrointestinal; FDA Food and Drug Administration Drug interactions: Terbinafine: antiarrhythmic agents, beta-blockers, SSRIs, tricyclic antidepressants, and warfarin; Itraconazole: benzodiazepines, calcium channel blockers, proton pump inhibitors, statins, and warfarin; Fluconazole: benzodiazepines, calcium channel blockers, statins, and terfenadine

The nail is examined for fungal hyphae, arthrospores, or Treatment of fungal nail infections varies depending on the yeast forms; however, direct microscopy cannot always iden- responsible organism and the severity of the infection. Topical tify the specific fungus. Cultures from nail bed or nail plate antifungal treatment is difficult to perform and often remains debris are performed for confirming diagnosis and ascertain- unsuccessful, while systemic treatment is effective but may be ing the exact etiologic fungus. Different media are used, associated with side effects. The usual duration of treatment with including primary medium containing cycloheximide, which oral antifungals is 6–8 weeks for fingernail involvement and is directed against most NDM and bacteria, e.g., DTM myco- 12 weeks or longer for toenail involvement (Table 34.1). Despite sel (BBL), mycobiotic (DIFCO), and cycloheximide-free­ the number of available antifungal drugs, not all patients with secondary media, but with addition of antibiotics to elimi- onychomycosis are cured because of nonadherence to treatment, nate bacterial contamination, e.g., Sabouraud glucose agar, incorrect diagnosis, or advanced disease. Moreover, there are Littman Oxgall medium, and potato dextrose agar [5]. long-term recurrence rates, ranging from 10 to 53% [9]. 372 M. El-Domyati and N. H. Moftah

34.2 Nail Abnormalities in Dermatoses are indicated in management-resistant nail psoriasis, with or without cutaneous and psoriatic arthritis [13]. Treatment 34.2.1 Eczematous Dermatitis of nail psoriasis is often a time-consuming challenge for the physician with variable outcome; relapses are com- Chronic eczematous dermatitis of hands and feet may pre- mon [14]. cede a variety of nail changes. The nail changes include roughness, thickening, coarse and irregular pitting or groov- ing, transverse ridging, furrowing, nail shedding, onycholy- 34.2.3 Pityriasis Rubra Pilaris sis, and subungual hemorrhage. Acute and chronic paronychial inflammation which affects nail matrix second- Nail changes are common in pityriasis rubra pilaris (PRP) arily may lead to nail plate dystrophy. In hot climate zones, involving roughly 80% of the patients [15]. They are asso- long-standing dyshidrotic eczema with dystrophic nail ciated with type I adult onset PRP, especially with affection changes may develop. Reactions to artificial nails have of the palms and soles. The nails are thickened and discol- included paronychia, onychodystrophy, and dermatitis at ored distally with splinter hemorrhages. Nail dystrophy is contact areas [10]. less common in juvenile type V PRP. Psoriasiform pitting can occur in circumscribed type IV PRP (Fig. 34.4). Wedge-shaped­ thickening has been reported in type VI dis- 34.2.2 Psoriasis ease associated with human immunodeficiency virus infec- tion [15]. Pitting of the nail plate is the most common sign in psoria- sis in around 15% of all patients, ranging from small pits to large irregular furrows (Figs. 34.2 and 34.3); it occurs in 34.2.4 Lichen Planus up to 80–90% of patients with psoriatic arthritis [11]. Pitting results from defective keratinization of the proxi- occurs in <1% of the population with a par- mal matrix cells, with falling out of small foci of parakera- ticularly high rate in India [16]. Nail involvement appears totic cells on the nail plate. Pitting can be seen also in with cutaneous lichen planus in 3–15% in Caucasians with , eczema, trauma, and pityriasis rubra pila- fair skin, reaching up to 18% in populations with dark skin, ris. Salmon or oil-­drop patches are a specific diagnostic or even in absence of cutaneous lesions [17, 18]. The etiol- sign of psoriatic nail; it is a translucent, yellowish-red dis- ogy of the disease is unknown; various potential triggers, coloration in the nail bed that appears like spots or drops such as viral or bacterial antigens, metal ions, drugs, or of oil under the nail plate. The yellow color results from physical factors, could initiate the autoimmune process parakeratotic and acanthotic processes of nail bed, while [16]. Lichen planus of the nail matrix can result in diverse the reddish tones occur due to presence of plaques on the morphological alterations of the nail plate. The commonest nail bed. Crumbling and nail plate thickening are observed change is longitudinal fissuring and ridging of the nail plate in psoriasis after a prolonged period of persisting disease () arising either alone or in combination with activity leading to total nail matrix destruction [11]; also, distal splitting and thinning; the area of the nail matrix may may occur (Fig. 34.4). Diagnosis is usually appear prominent (Fig. 34.5). Similar changes are seen in made by presence of cutaneous lesions of psoriasis else- old age, Darier’s disease, alopecia areata, and vitiligo. where. Direct microscopic examination should be per- Pterygium, which is detected in 6% of the patients [18], formed to exclude onychomycosis which may coexist. occurs as a result of adhesion of cuticle and matrix leading Matrix or nail bed biopsies show as a major criterion neu- first to a split nail and later to onychomadesis and possible trophils, with parakeratosis, focal hypogranulosis, and complete loss of the nail plate [17] resembling psoriasiform hyperplasia of the nail bed as minor (Fig. 34.6). Also trachyonychia may be present in lichen criteria [12]. affecting several or all nails. The clinical diagnosis is con- Treatment of nail psoriasis requires consequent appli- firmed by histopathological examination in biopsies taken cation of topical remedies, intralesional injections, and in from the nail matrix, especially if cases with isolated nail severe cases systemic administration of drugs such as oral involvement. retinoids. Application of intralesional corticosteroids is a Treatment of nail lichen is difficult and disappointing. second step after unsuccessful topical formulations Retinoids, especially acitretin, occasionally combined with (Tables 34.2 and 34.3). Conventional systemic therapies PUVA can be administered (Table 34.4). 34 Nail Disorders in Dark Skin 373

Fig. 34.2 Plaque-like psoriasis and psoriatic nails in African males showing thickening of the nail plate with irregular pitting (Uganda; courtesy CEO) 374 M. El-Domyati and N. H. Moftah

Fig. 34.3 Nail psoriasis in Egyptian young males showing pitting in the form of multiple irregular punctate depressions with random distribution

Fig. 34.4 Thickened nails and pitting of both thumbs in pityriasis rubra pilaris (left) and secondary leukonychia affecting nails of a patient with psoriasis (right)

34.2.5 Alopecia Areata 34.2.6 

Involvement of the nail is regularly found in white This rare clinical syndrome is a triad consisting of characteristic Caucasians (7–66%) [15, 19] and is also common in dark discoloration of the nails, lower limb , and pulmo- skin populations with alopecia areata (44%) [20]. It seems nary manifestations such as bronchiectasia, chronic cough, and that inflammatory cells targeting the hair follicles also pulmonary effusion [21]. Chronic is frequently associ- interfere with keratinization in nails. Nail involvement in ated and lymphatic impairment is often evoked. The syndrome alopecia areata may either precede or follow the develop- has been also described in an Arab boy with facial dysmorphism ment of hairless patches on the scalp. Clinically, rough- and bilateral conjunctival pigmentation born to consanguineous ness and fine superficial pitting of the nail plate in a parents [22] and also from India [23]. It is characterized by geometric pattern are seen, together with longitudinal arrested nail growth, whereby fingernails and toenails are exces- ridging and sometimes red lunulae; trachyonychia and sively hard and curved from side to side with diffuse pale yellow Beau’s lines can also be seen in alopecia areata [19, 20], to dark yellow-green discoloration (Fig. 34.8). Absent cuticle particularly in well-developed cases and long duration and paronychia may be seen and secondary onycholysis is fre- (Fig. 34.7). If the diagnosis of alopecia areata is not read- quent. Treatment is symptomatic. Oral vitamin E alone or asso- ily apparent, a biopsy of the nail matrix shows mild to ciated with triazole antifungals may achieve partial or total moderate dense lymphocytic infiltrate associated with exo- disappearance of nail discoloration [21]. cytosis and spongiosis. For treatment, topical and intralesional administration of triamcinolone (2.5–3 mg/mL once a month) is helpful when 34.2.7 Vitiligo spontaneous clearing of the nails does not occur. Nail changes may persist for a long period of time after complete Vitiligo, an acquired pigmentary skin disorder, affects 0.1– hair regrowth [19]. 4% of the population. Nail abnormalities are evident in up to 34 Nail Disorders in Dark Skin 375

Table 34.2 Topical and intralesional treatment of nail psoriasis Medication Dosing Prognosis Potential adverse effects Topical corticosteroids Betamethasone dipropionate – Equal efficacy on both nail – Telangiectasias, cutaneous ointment 2×/day or clobetasol matrix and bed signs atrophy, tachyphylaxis, rebound propionate 0.05% cream under flare, systemic absorption occlusion for 12–20 weeks Topical vitamin D3 Calcipotriol ointment (50 g/m2 – Signs of significant – Local irritation, derivatives per week) 2×/day for 20 weeks improvement of the nail bed hypercalcuria, hypercalcemia – Combination of betamethasone dipropionate and calcipotriol ointment Tazarotene Tazarotene 0.1% gel 1×/day for – Significant improvement of – Local irritation, erythema, 12–24 weeks onycholysis and pitting only nail fold desquamation – Improvement in hyperkeratosis and oil spots Topical calcineurin Tacrolimus 0.1% ointment 1×/day – Equally effective on nail inhibitors at nail folds bed and nail matrix signs Anthralin Dithranol in petrolatum 0.4–2% – Improvement of nail bed – Local irritation, staining of ointment to the affected nail bed signs and, to a lesser extent, the nail plate, skin, and cloths and then washing after 30 min for pitting 20 weeks 1% fluorouracil solution 2×/day for 24 weeks – No or poor response – Localized inflammation, infection, discoloration Topical cyclosporine 70 mg/mL maize-oil-dissolved – Improvement of both nail – Yellowish discoloration oral cyclosporine solution for bed and matrix 12 weeks – Not as effective as its systemic form due to its inability to penetrate the stratum corneum and instability in topical emulsion Intralesional injection of – Injections of triamcinolone – Efficacy on nail bed – Short-term paresthesia, triamcinolone acetonide acetonide 5 mg/mL/month for psoriasis focal pain, hematoma, 6 months in proximal nail fold reversible nail fold atrophy and then 4 injections over the next 6 months and every 2 months for final 6–12 months – Injection of 10 mg/mL (0.1 mL in each of 4 periungual sites) every 2 months, for symmetrical delivery to nail matrix and nail bed

78% in fair skin populations and in 68% of patients with dark or as a result from constant exposure to petrolatum-­based sol- skin [24, 25]. The most common nail changes in vitiligo vents (Fig. 34.7c). may also be idiopathic in include longitudinal ridging and absent lunula. Other healthy toenails representing a normal variant in infancy. reported nail abnormalities are punctate leukonychia, pitting, Trachyonychia shows dull, rough, and fragile nail plate, flag sign, and Terry’s nails [24, 25]. with loss of luster and transparency (opaque, muddy, grayish-­ white discoloration) presenting the appearance of sandpaper nails. The term twenty-nail dystrophy is specifically used to 34.3 Nonspecific Nail Changes describe trachyonychia involving all 20 nails. Trachyonychia can also be seen in lichen planus, alopecia areata, vitiligo, and Koilonychia or spooning of nails occurs when the free edge of Darier’s disease. In psoriasis it exhibits a more thickened nail the nail is averted with transverse and longitudinal concavity. plate as opposed to the thinning noted in lichen planus [27]. It can be associated with some genetic diseases such as patella- Leukonychia is an abnormal, immature keratinization of nail syndrome and trichothiodystrophy, as well as iron-defi- the nail matrix resulting in white discoloration of the nail ciency anemia, B12 deficiency, and endocrine conditions [26], plate. It may occur as primary, true leukonychia due to 376 M. El-Domyati and N. H. Moftah

Table 34.3 Photochemotherapy, laser, and systemic drug treatment of nail psoriasis Treatment Dosing Prognosis Potential adverse effects Laboratory Monitoring PUVA – Oral PUVA management, 2–3×/ – Effective in both nail – No incidence of adverse week, 8-methoxypsoralen (0.6 mg/kg) bed and matrix signs effects – Topical PUVA, 2–3×/week, using 1% solution 8-methoxypsoralen to proximal nail fold Pulsed dye – 1×/month session for 3 months – Improvement in nail – Temporary pain, laser bed signs resolving purpura Methotrexate – 15 mg/week, in 2 divided doses – 43% improvement – Hepatotoxicity, – Liver and renal for 24 weeks in nail matrix findings leucopenia, aplastic function tests anemia ulcerative stomatitis, Complete blood count gastrointestinal disturbances – Pregnancy test Cyclosporine – 3–5 mg/kg/day – More powerful and – Renal dysfunction, – Blood pressure – Combination of calcipotriol faster than other hypertension, headache, – Serum creatinine (occlusive application at night) conventional systemic paresthesia, , + oral cyclosporin (3–4.5 mg/kg/day) therapies gingival hyperplasia, for 3 months – More efficacy in gastrointestinal disorders, nail bed than nail matrix malignancies signs Acitretin 0.2–0.3 mg/kg/day for 6–12 months – Moderate efficacy – Teratogenicity, – Liver function tests (40–50%) particularly hepatitis, hyperlipidemia, – Blood lipids on nail bed signs mucocutaneous dryness, – Pregnancy test progressive nail atrophy. So, it is used in thickened nails TNF-α inhibitors Infliximab – i.v. infusions of 5 mg/kg – 78–80% – Anaphylactic reactions – Screening for infliximab at weeks 0, 2, and 6 and improvement at (up to 1 h after intake), type tuberculosis every 8 weeks week 50 IV delayed hypersensitivity – No vaccinations reaction (3–12 days after intake). Rarely, demyelinating diseases, congestive heart failure, lymphoma, lupus-like syndrome Adalimumab – s.c. injections of 80 mg, then – Significant As infliximab As infliximab 40 mg every other week improvement at week 12 and complete resolution of nail signs at week 24 Etanercept – s.c. injections 2 × 50 mg/week – 51% improvement As infliximab As infliximab for 3 months and then 50 mg/week after 54 weeks for 3 months Anti-IL monoclonal antibodies Ustekinumab – s.c. injection 45 mg (or 90 mg if – 20% improvement As infliximab As infliximab body weight >100 kg) of pitting, 30% of onycholysis Secukinumab – s.c. injection 150 mg at weeks – 19% improvement As infliximab As infliximab 0, 1, 2, 4 overall

involvement of the nail matrix in congenital defects, or as sec- bands are seen in candidiasis, Darier’s disease, and after the ondary, punctate, transverse, or striate leukonychia, being a use of quinacrine [28]. result of trauma, onychomycosis, diabetes, systemic infec- is a transverse over curvature of the nail plate. tions (measles, typhus, scarlet fever, diphtheria, and syphilis), It may be inherited or acquired as it is associated with psoria- and arsenic or lead poisoning. Diffuse type of leukonychia sis, onychomycosis, nail tumors, systemic lupus erythema- may be associated with leprosy, hemochromatosis, hypocal- tous, Kawasaki disease, and use of beta-blocker [29]. cemia, and acanthosis nigricans (Fig. 34.9). Transverse leuk- Beau’s lines are horizontal grooves on the nail plate, onychia occurs as Mees’ lines, whereas white longitudinal involving several or all nails. They reflect an interruption of 34 Nail Disorders in Dark Skin 377

Fig. 34.5 Lichen planus of the nails in an African male showing linear fissuring, ridging, and irregular depressions resembling koilonychia. Note the swelling of the nail matrix (courtesy: CEO)

ally in pulmonary or cardiovascular diseases, ulcerative colitis, and hepatic cirrhosis. It is assumed that digital club- bing may develop from increased blood flow within the microvasculature [30]. Onychocryptosis (ingrown nails) results when part of the nail plate pierces the lateral nail fold. Three major types are known: over-curvature of the nail plate (pincer nail), subcu- taneous ingrowing toenail, and hypertrophy of the lateral nail fold. Clinically, onychocryptosis manifests as inflam- mation of the nail fold, often with granulation tissue forma- tion causing considerable tenderness of the involved digit and pain [31]. Terry nails are characterized by a proximal white color that extends from proximal nail fold obscuring the lunula to Fig. 34.6 Anonychia of all fingers resulting from scarring dystrophy in narrow distal red/brown band (0.5–3 mm width). Some acrodermatitis continua suppurativa Hallopeau nails show white color only without reddish hue; pressing on the nail plate alters the color of the nail. Terry nails are nail bed mitosis. In dark skin populations, they are present represented in 30.6% of patients with chronic systemic dis- particularly in poor nutritional status, severe illness, high eases, especially with liver cirrhosis (80%), congestive fever, trauma, and sensitivity to drugs (Fig. 34.7b). heart failure (52%), diabetes mellitus (49%), and even Digital clubbing is characterized by fibrovascular hyper- aging. This condition may be caused by a decrease in vascu- plasia of the distal fingertip tissue presenting an increased larity and an increase of connective tissue in the nail bed longitudinal and horizontal curvature of the nail plate of (Fig. 34.10) [29, 32]. both finger- and toenails. In clubbing, the angle of Lovibond Half-and-half nails show proximal white half and distal (the angle between the nail plate and proximal nail fold red/brown half (20–60%) due to changes in nail bed color. It when viewed from the side) is greater than 180°, whereas it occurs as the most common sign of renal insufficiency, is less than 160° in normal nails. Clubbing is seen occasion- which shows also absent lunula and splinter hemorrhages 378 M. El-Domyati and N. H. Moftah

Table 34.4 Commonly prescribed medications for lichen planus Medication Dosing Prognosis Potential adverse effects Topical steroids – Daily application of high – Poor response to topical steroid Telangiectasis, cutaneous potent topical steroids atrophy, tachyphylaxis, rebound flare, systemic absorption Topical calcineurin – Tacrolimus ointment, twice – Improvement within 6 months No side effects inhibitors daily Intralesional injection of – Injections of 2.5–10/mL – Complete cure after 2–6 months, – Short-term paresthesia, triamcinolone acetonide triamcinolone acetonide in but with recurrence transient focal pain, hematoma proximal nail fold formation, reversible nail-fold atrophy, rupture of extensor tendon Systemic corticosteroids – Prednisolone – Complete cure after 2–6 months – No tolerance to the side (0.5–1 mg/kg daily orally) – Complete cure after 6–8 months effects of systemic – Intramuscular injection of (fingernails up to 8–12 months corticosteroids. Recurrence triamcinolone acetonide (toenails) was common (0.5–1 mg/kg/month) was prescribed to children with typical nail lichen planus for 3–6 months until the proximal half of the nail was normal Methotrexate – 10–20 mg/week, Significant improvement of subcutaneously nail fold erythema, edema, and trachyonychia a few weeks after initiation of the treatment Biological therapies – Subcutaneous injection of – Marked improvement No side effects etanercept, 25 mg twice weekly within 6–9 months for the first 6 months and 50 mg once weekly thereafter

[33] (Fig. 34.11). Roughly 60% of persons with chronic Splinter hemorrhages appear as small linear structures, renal disease have nail manifestations [15]. about 2–3 mm long, and are arranged at the distal end of the Mees’ lines are transverse white lines that may extend the nail plate. They reflect rupture of wide caliber vessels and complete width of the nail plate of single or multiple digits. tracking of extravasated blood down the longitudinal furrows Since the abnormality is in the nail plate and not the nail bed, beneath the nail plate. The most common cause of splinter Mees’ lines migrate toward the distal end of the nail plate over hemorrhage is trauma, followed by psoriasis, and then endo- time; they often indicate arsenic poisoning or renal failure [26]. carditis if they are located in the proximal part on the nail Muehrcke lines are pairs of transverse white lines caused plate, embolic events, and after certain medications. They by edema within the nail bed, occasionally associated with may also occur in healthy individuals with increased capil- hypoalbuminemia. They do not migrate distally as the nail lary fragility and nail trauma. grows since they originate in the nail bed and not the nail plate Red lunula is nonspecific finding as it is present in and disappear when pressure is applied to the nail plate [26]. alopecia areata, rheumatoid arthritis, congestive heart Dilated periungual capillaries may be seen in the proxi- failure, pulmonary disorders, and carbon monoxide mal nail folds in patients with rheumatoid arthritis, systemic poisoning­ [26]. lupus erythematosus, dermatomyositis, or scleroderma; Subungual hematomas are painful red to black discolor- examination with a magnifying glass may show irregular, ations mostly caused by traumatic bleeding in the underlying twisted, and dilated vessels. These attributes give the area an vascular tissue of the nail bed. The faint reddish coloration of injected, erythematous appearance when viewed with the hemorrhage may not be easily identified in populations with naked eye. In addition, scleroderma shows pterygium inver- dark skin and be misdiagnosed. If no nail bed laceration is sum unguis especially with fingertip ulcerations and scar- suspected, treatment consists of drilling a hole through the ring. Nail affection ranges from 20% in systemic lupus nail with an electrocautery device or treatment with CO2 erythematosus up to 80% in scleroderma [15]. laser to relieve the pressure. 34 Nail Disorders in Dark Skin 379

Fig. 34.7 (a) Superficial pitting and longitudinal ridging in alopecia areata. (b) Loss of cuticle and a roughened nails with Beau’s lines in chronic eczema of an aged patient. (c) Koilonychia showing the averted free edges of the nails with longitudinal and transverse concavities

b

c

Onycholysis is detachment of the nail plate from the nail 34.4 Nail Disorders in Aging bed along the distal margin of the nail plate that becomes white, often encircled by an erythematous border. Some pos- In geriatric populations nail changes are due to impaired cir- sible causes of onycholysis are onychomycosis, psoriasis, culation and susceptibility of the senile nail apparatus to fun- hyperthyroidism, drug intake, or trauma. In so-called idio- gal infections, faulty biomechanics, neoplasms, concurrent pathic cases of onycholysis, anemia and asymptomatic thy- cutaneous or systemic diseases, and related treatments. In roid disease should be excluded. populations with dark skin, nail changes range from 88% in 380 M. El-Domyati and N. H. Moftah

Fig. 34.8 Yellow nail syndrome with excessively hard curved fingernails and toenails showing pale to dark-yellow discoloration. Secondary onycholysis is seen in both ring fingers

Fig. 34.9 Diffuse leukonychia in all fingers

Egypt [34] to 98% in India [35]. The commonest age-related nails in 33% of the patients, transverse ridges in 23%, and nail changes seen were pale, dull, opaque, brittle, and luster- lamellar split in 15% of cases [31]. Rough nails, transverse less nails, with decreased lunula visibility and onychor- ridges (Beau’s lines), and lamellar split were also reported in rhexis. The fingernails were more affected than the toenails other aging populations [31]. Bony deformities of the digits, [32]. It has been reported from India that among the age-­ infrequent nail cutting, or ill-fitting shoes can cause faulty related changes of the nail surface, prominent longitudinal biomechanics leading to onychodystrophies such as onycho- ridges were the commonest (85%), followed by rough gryphosis, onychophosis, onychocryptosis, onycholysis, and 34 Nail Disorders in Dark Skin 381

ab

c d

Fig. 34.10 Terry nails. White nail beds all over the whole nails (a, b) and proximal white nails with narrow distal red/brown band in liver cell failure (c, d)

Fig. 34.11 in a patient with renal failure

subungual hematomas. mostly involves Treatment of nail disorders in the elderly includes conserva- the great toenail with enlargement, opacity, and thickening tive management by periodic trimming of the nail plate and use of the nail plate as well as hypertrophy of the underlying nail of appropriate footwear. Onychophosis can be treated by bed resulting in “ram hornlike” or “oyster-like.” appearance. debridement of hyperkeratotic tissue by means of keratolytics The nail plate initially grows upward and thereafter deviates (urea 20%, lactic acid 12%, or salicylic acid 6–20%), followed laterally toward the other toes. by application of emollients. In severe and intractable cases, sur- 382 M. El-Domyati and N. H. Moftah

Fig. 34.12 Ridging and V-shaped notching of the free a edges of some nail plates in ectodermal dysplasia (a, b) and small, ridged, discolored, and dystrophic nails in Darier’s disease (c)

b

c

gical or chemical nail avulsion (phenol), with or without exci- occur. Ectodermal dysplasias present with nail disorders as sion of the involved adjacent tissue (nail folds, bed, or matrix), anonychia or brittle, thin, ridged, and discolored nails. Nail can be employed in persons with sufficient vascular supply [31]. dystrophy is an important component of the hidrotic type, in which nails are thickened, striated, and discolored [36] (Fig. 34.12). Nail changes such as pitting, transverse and 34.5 Genetic Nail Disorders longitudinal ridging, and even dystrophy manifest in inconti- nentia pigmenti [37]. These include anonychia (absence of nails), koilonychia Nail aplasia or dysplasias, particularly with presence of tri- (concave curvature of the nail), micronychia (small nails), angular lunulae, are characteristic for the nail patella syn- polynychia (more than one nail on a digit), and brachyonychia drome, an autosomal dominant disorder caused by mutations­ (racket nails) [36]. Some changes of the nails are clinical in the LMX1B gene; the condition includes aplastic or hypo- markers of an underlying multiorgan genodermatosis. plastic patella and nephropathy, and onycholysis may occur In pachyonychia congenita, massive thickening of the nail with destruction of the underlying terminal phalanges [38, 39]. bed and brown discoloration of the nail plate with upward In another autosomal dominant entity, epidermolysis bul- angulation of the distal free edge of the thickened nail plate losa simplex, the nails may be normal early in life, but 34 Nail Disorders in Dark Skin 383 repeated traumas usually lead to scarring and dystrophy. In subungual involvement leading to onycholysis [45]. It can dystrophic type, there is scarring with mitten-like deformity develop to invasive squamous cell carcinoma indicated by of the digits due to loss of matrix. In junctional and acquired the occurrence of nodules, hemorrhage, and ulceration. It is epidermolysis bullosa, the nails are thickened and dystrophic more common on fingers (thumb and index) than toes with [40]. Darier’s disease may show nail affection in 92% of multiple finger involvement in immunocompromised carri- patients. It presents with nail matrix (splitting, fragility, and ers. Treatment is Mohs surgery or amputation of the digit for red and white longitudinal streaks; Fig. 34.12) and distal nail more deeply invasive lesions involving periosteum [46]. bed signs such as subungual hyperkeratosis with overlying Acral lentiginous melanoma is a rare subtype of malig- V-shaped notches at the free edge [41]. Also, twenty-nail nant melanoma but still the most common melanoma sub- dystrophy may occur [27]. type in populations with pigmented skin (see Chap. 36). It arises usually with longitudinal melanonychia appearing as pigmented band of the nail plate, extending from the nail 34.6 Tumors of the Nail Apparatus matrix to its periungual free edge [47]; dermoscopic exami- nation may provide useful information to the dermatologist Nail-specific tumors may arise from all tissues of the nail and facilitate the recognition of an underlying subungual apparatus; most of them are slowly growing neoplasms of melanoma [48]. In contrast to fair skin patients, melano- low malignancy, also reported in patients with pigmented nychia may also be presented in healthy persons with dark ethnic skin. Onychomatricoma, onychocytic matricoma, skin spontaneously or after drug intake (e.g., zidovudine, onychocytic carcinoma, and onychopapilloma all originate hydroxychloroquine), trauma of the nail matrix, or in pres- from the nail matrix, whereas onycholemmal and pro- ence of junctional melanocytic nevi [49]. liferating onycholemmal tumors originate from the nail bed [42]. In particular, onychomatricoma has been recently described [43], often on the great toenail, while giant nail References dystrophy may mask the tumor and be an obstacle for its surgical removal. Slowly growing onycholemmal carcino- 1. Astur Mde M, Farkas CB, Junqueira JP, et al. Reassessing melano- mas also occur. nychia striata in phototypes IV, V, and VI patients. Dermatol Surg. 2016;42:183–90. Glomus tumor is a benign nail bed lesion, presenting 2. Rockwell PG. Acute and chronic paronychia. Am Fam Physician. with intense pinpoint throbbing pain, which is exacerbated 2001;63:1113–6. by pressure or cold temperature. 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Braz J Microbiol. 2015;46:799–805. able sizes causing nail plate depressions. Myxoid pseudocyst 7. Yadav P, Singal A, Pandhi D, et al. Clinico-mycological study of of digits (digital mucous ) is the commonest benign dermatophyte toenail onychomycosis in New Delhi, India. Indian J Dermatol. 2015;60:153–8. tumor originating in the proximal nail fold compressing the 8. Singal A, Khanna D. Onychomycosis: diagnosis and management. matrix and causing depressed longitudinal grooves in the Indian J Dermatol Venereol Leprol. 2011;77:659–72. nail plate. Pseudocysts are formed by focal accumulations 9. Westerberg DP, Voyack MJ. Onychomycosis: current trends in of mucin in the without a defined cyst wall. They can diagnosis and treatment. Am Fam Physician. 2013;88:762–70. 10. Kumar S, Shilpa K. Nail changes in other dermatological condi- be treated with intralesional injections of triamcinolone or tions. In: Sacchdanad S, Savitha AS, editors. Nail and its disorders. surgical removal [44]. 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