10 Irritant Contact Dermatitis of the Nails

Patricia G. Engasser

Contents ena) due to irritant reactions can subsequently lead to psoriasis or lichen planus of the nails. 10.1 Mechanical Irritation . . . 89 10.1.1 Recreational . . . 89 10.1.2 Occupational . . . 89 10.1 Mechanical Irritation 10.1.3 Cosmetic . . . 90 10.1.4 Miscellaneous . . . 90 10.1.1 Recreational 10.2 Physical Agents . . . 90 10.2.1 Irradiation . . . 90 10.2.2 Foreign Matter . . . 90 Splinter hemorrhages form when blood leaks from 10.2.3 Moisture . . . 90 the longitudinally oriented blood vessels of the nail 10.3 Chemical . . . 90 bed and on some occasions, are related to trauma. 10.3.1 Medicinal . . . 90 More noticeable are the subungual hematomas that 10.3.2 Occupational . . . 91 result from trauma. Athletes participating in sports 10.3.3 Cosmetics . . . 91 such as tennis or track, commonly develop hemato- 10.3.4 Miscellaneous . . . 91 mas below the toenails. 10.4 Biological . . . 92 Nail biting, tics, or habits of fiddling with nails at 10.5 Prevention and Therapy . . . 92 their base can cause injury to the matrix and produce References . . . 92 nail plate dystrophies [1]. Chronic trauma from faulty ambulatory biomechanics can result in nail plate hy- pertrophy, subungual corns, ingrown toenails, and onychogryphosis [2]. Some cases of longitudinal mel- Nails have served our species well since the dawn of anonychia form from footwear causing friction, but mankind, but fingernails are frequently traumatized frequently this diagnosis requires a biopsy to differen- functioning as tools. When man adopted closed shoes, tiate it from melanoma [3]. the toenails were exposed to a generally warmer, moister atmosphere. Though shoes protect the nails from some trauma, ill-fitting shapes also damage the 10.1.2 Occupational nail. Irritant environmental factors that cause nail damage may be categorized as mechanical, physical, Acute injury with a tool such as a hammer can cause chemical, and biologic. Frequently these factors act nail dystrophy and even permanent destruction, but together to irritate the nail unit. Four keratinizing this diagnosis is usually obvious. Nail dystrophy components of the nail unit are: posterior nail fold, caused by repeated minor trauma is frequently not nail matrix, nail bed, and hyponychium. Injuring any recognized. Distal onycholysis was reported in a component may result in change in appearance of the chicken-processor who plucked the chickens with his horny nail plate. Irritant hand dermatitis from any bare fingers [4]. Mushroom growers who lift heavy cause involving nail folds or fingertips may cause nail plastic bags also develop onycholysis frequently ac- changes. Isomorphic responses (Koebner phenom- companied by koilonychia, nail splitting, and splinter 90 Patricia G. Engasser

hemorrhages [5]. Koilonychia attributed to trauma 10.2.2 Foreign Matter has been reported in toenails of rickshaw pullers [6], and fingernails in a pin threader [7], a coil winder [8], Barbers and hairdressers may have the skin of their and car mechanics [9]. Beau’s and Mees’ lines have fingertips or hyponychium invaded by small pieces of both been observed caused by trauma [10]. hair, and these foreign bodies cause onycholysis. Sim- ilar injury to the posterior nail fold causes paronychia to form. Onycholysis develops with penetration of 10.1.3 Cosmetic thorns, splinters, bristles, fibrous glass, and pieces of metal in other occupations [17]. Granulomatous Manicures may include removal of remnants of nail lesions and split nail deformities develop from pen- polish, shaping the nail plate, and pushing back cu- etrating wounds from sea urchin spines in fishermen ticle off the nail plate and/or clipping it. Rigorous at- and divers [18]. tacks on the cuticle with instruments can temporarily injure the distal nail matrix below resulting in leuk- onychia striata [11], and in some cases permanent 10.2.3 Moisture nail deformity [12]. Cuticle destruction leads to paronychia and nail plate dystrophy. Vigorously cleaning Immersion of the hands in liquid that leads to mac- debris and dirt below the distal free end of the nail eration of the skin of the posterior nail fold ultimately plate with sharp instruments injures the hyponych- predisposes to chronic paronychia. Many occupa- ium causing onycholysis. Nails that are buffed too vig- tions require immersion of the hands or conditions orously become transversely grooved [13]. which keeps the hands moist—custodians, cooks, kitchen helpers, health care workers, and housewives to name only a few. Invasion of the posterior nail fold 10.1.4 Miscellaneous by microorganisms can follow, leading to chronic in- flammation. Kern discusses the early occupational Challenges to the clinician’s acumen arise when nail diseases literature, which showed that immersion hemorrhages are noted in a seriously ill patient unable accompanied by mild trauma also leads to onycholy- to provide a history to designate the cause as trauma sis [19]. In 1931, in a ketchup bottling plant, work- rather than bacterial endocarditis. In a reported ex- ers who removed excess glue from bottles immersed ample, a neurologist’s maneuver of pushing the base in warm water by picking it off with their fingernails of the nail with a pen to prompt a pain response in developed onycholysis within 48 h. As with washer- a comatose patient resulted in puzzling subungual women, observed previously, the combination of wa- hematomas. An observant nurse’s history led the der- ter immersion and trauma led to nail changes. Irritant matologists to the correct conclusion about the trau- reactions of the nail often involve different combina- matic origin [14]. tions of mechanical, chemical, physical, and biological injuries. The role of hydration in the development of ony- 10.2 Physical Agents choschizia (lamellar dystrophy) has been studied ex- perimentally by soaking pieces of nail plate in liquid. 10.2.1 Irradiation Onychoschizia was produced by successive hydration and dehydration of these pieces of nail over 3 weeks The nail plate is rather resistant to ultraviolet light but not by hydration alone [20]. damage. However, patients who ingest photosensi- tizing drugs, such as the tetracyclines, followed by intense ultraviolet light A (UVA) exposure, develop 10.3 Chemical photo onycholysis. Inadvertent exposure to microwave radiation in two snack bar employees was impli- 10.3.1 Medicinal cated in the development of Beau’s lines [15]. Chronic, small, irregular, occupational X-ray exposure has Irritant concentrations of chemicals are used for ther- been noted to cause the nails to become brittle and apeutic purposes. By applying 40% urea paste under crack easily [16]. In the example of koilonychia in a occlusion to the nail plate, South and Farber refined pin threader sited above under mechanical injury, lo- a technique for nonsurgical avulsion of dystrophic cal heat was also involved in the working conditions toenails [21]. The paste is occluded for 7 days. Appli- and was a contributory factor [7]. cation of the dressings requires exquisite care so the 10 Irritant Contact Dermatitis of the Nails 91 skin folds surrounding the nail plate are protected file, and methacrylic acid is applied. MA nails adhere from this concentration of urea to prevent more ex- poorly and require more abrasion and nail plate thin- tensive irritation. This technique is particularly use- ning to adhere. MA nails are tougher and reportedly ful for elderly individuals who may be immunosup- transfer more traumatic forces to the natural nail pressed, diabetic, or anticoagulated. plate resulting in more frequent splitting of the nail Permanent destruction of the matrix of dystro- plate near the matrix [27]. Onycholysis and paro- phic toenails is a common therapeutic maneuver, nychia caused by allergic reactions to these methac- and partial matricectomy is used to treat recurring rylates usually occur after several months of this type ingrown toenails. Traditionally, matricectomy is per- of nail grooming, but there has been little recognition formed by applying 89% phenolic acid to the exposed of the nail thinning and irritant reactions that pre- matrix [22]. dispose to the development of allergy. A distressing adverse effect of sculptured nails has been paresthesia. Baran and Schibli reported permanent paresthesia in 10.3.2 Occupational a patient who did not have an allergic reaction to the monomer, suggesting that this was a direct effect on The most dramatic chemical irritant reactions of the nerves [28]. nail unit are caused by hydrofluoric acid. Hydro- During manicures, cuticle remover is applied to fluoric acid can etch glass and is used in foundries, the base of the nail to soften the cuticle by breaking glassworks, and in semiconductor manufacture. The the disulfide bonds of keratin, so that the cuticle can fluoride ion penetrates the skin freely interfering be pushed back or abraded. Cuticle removers fre- with calcium activity and causing deep tissue injury, quently contain sodium hydroxide, potassium hy- in some cases, without initial pain. Clinicians must droxide, inorganic salts of trisodium phosphate, or be aware of this to make the correct diagnosis. When triethanolamine. If the solutions are left in place too hydrofluoric acid penetrates under the free end of the long, they may irritate the posterior nail fold and de- nail plate, it causes tissue swelling and exquisite pain. stroy the cuticle, acting as a seal that prevents infec- Necrosis can eventuate in loss of the distal portion of tion [29]. Mechanical trauma accompanying this is the digit if the nature of the injury is not recognized discussed above. and treated promptly. For treatment, the nail plate is In the 1960s, nail hardeners were marketed that split or removed and calcium gluconate is injected di- were formaldehyde solutions and a series of reactions rectly into the nail bed or calcium gluconate is infused were reported that included onycholysis, paronychia, into the arterial supply of the effected digits [23]. and thickening of the hyponychium [30]. Many were Directly handling paraquat, a herbicide, damages reported as allergic reactions but were patch tested nail. The damage occurs from an acute exposure to with 5% formaldehyde solutions that may give irri- concentrated solutions of paraquat or to smaller re- tant patch test results. Cronin reported that patients peated exposures of more dilute solutions. Injuries seen at St. John’s Hospital for Diseases of the Skin, range from yellow or white discoloration to transverse with adverse reactions to these hardeners and patch ridging, or onycholysis to complete nail loss [24]. tested, were diagnosed as irritant rather than allergic Koilonychia is caused by chronic exposure to or- reactions [31]. ganic solvents such as thinners used by cabinetmak- Cosmetics not designed for direct application to ers and motor oils handled by mechanics [25, 26] the nails also can damage them. Thioglycolate hair removers cause onycholysis [32]. Hairdressers develop koilonychia from chronic trauma and exposure to 10.3.3 Cosmetics thioglycolate permanents [33].

Nail polish is removed by direct application of acetone or other nitrocellulose solvents for a few minutes, 10.3.4 Miscellaneous but removal of artificial nails requires long periods of soaking in acetone, thus exposing the skin surround- Daniel and associates report a retrospective study of ing the nail plate to defatting, drying conditions. In 137 patients with paronychia and onycholysis seen tests comparing removal of methyl methacrylate (MA) over 13 years. Patients were excluded if they had to ethyl methacrylate (EA) sculptured nails, MA nails skin diseases or dermatophyte infections as the pri- required soaking in acetone for 90 min compared to mary cause of these disorders. In the 93 patients with 30 min for EA nails [27]. Before sculptured nails are paronychia, 89 were noted to have exposure to con- molded on the nail, the nail plate is abraded with a tact irritants. The author did not detail the irritants 92 Patricia G. Engasser

but sited examples of soapy water, raw food, and nail 3. Baran R. Frictional longitudinal melanonychia: A new en- polish [34]. titiy. Dermatologica 1987; 174:280–284 4. Ronchese F. Nail defect and occupational trauma. Arch Dermatol 1962; 85:404 10.4 Biological 5. Schubert B, Minard JJ, Baran R, Verret JL, Schnitzler L. Onychopathy of mushroom growers. Ann Dermatol Vene- In the study quoted above 85% of the patients with reol 1977; 104: 627–630 onycholysis and 81% of the patients with paronychia 6. Bentley-Phillips G, Bayles MAH. Occupational koilony- grew yeast suggesting that this organism is commonly chias of the toe nails. Br J Dermatol 1971; 85:140–144 a secondary or an accompanying cause of these nail 7. Pedersen NB. Persistent occupational koilonychias. Con- disorders [34]. Chronic infections with yeast or bac- tact Dermatitis 1982; 8:134 8. Smith SJ, Yoder FW, Knox DW. Occupational koilonychias. teria often depend on preceding injuries disturbing Arch Dermatol 1980; 116:861 the integrity of the nail unit. The role that irritation 9. Dawber R. Occupational koilonychias. Clin Exper Derma- plays in chronic dermatophyte infections is not well tol 1977; 2:115–116 studied. Wearing shoes is an important predisposing 10. De Berker D. What do Beau’s lines mean? Int J Dermatol factor for developing tinea pedis and onychomycosis. 1994; 33:545–546 Tinea manum and onychomycosis are regarded as oc- 11. Samman PD. The nails in disease, 4th edn. William Heine- cupational when workers are exposed to mild trauma mann, London, 1986 and humid conditions [35]. 12. Barnett JM, Scher RK, Taylor SC. Nail cosmetics. Dermatol Clin 1991; 9:9–17 13. Braun JB. Grooving of the nail due to P. Shine. Cutis 1977; 10.5 Prevention and Therapy 19:323 14. Pierson JC, Lawlor KB, Steck WD. Pen push purpura: iat- Clearly prevention of irritant reactions is the most rogenic nail bed hemorrhages in the intensive care unit. important step. Much of this can be categorized as Cutis 1993; 51:422–423 prudence and caution. Shoes should fit properly and 15. Brodkin DH, Blieberg J. Cutaneous microwave injury. Acta be adjusted for changes in gait and foot deformities. Derm Venerol 1973; 53:50–52 Using properly designed tools to perform tasks rather 16. Cohen R. Radiation effects. In: Adams RM (ed) Occupa- than fingernails can prevent injury. Avoid aggressive tional skin disease, 3rd end. WB Saunders Co., Philadel- manicures; they should be gentle. Nails that are ony- phia, 1999; pp 58–68 cholytic should be cut short. Protect hands from ex- 17. Adams R. Effects of mechanical trauma on nails. Am J Ind posure to chemicals with the proper gloves that have Med 1985; 8:274–280 kept their integrity [36]. To understand and prevent 18. Haneke E, Tosti A, Piraccini BM. Sea urchin granuloma of occupational causes of nail injury, a careful history the nail apparatus: Report of 2 cases. Dermatology 1996; 192:140–142 may need to be supplemented by the clinician mak- 19. Kern DG. Occupational disease. In: Scher RK, Daniel CR ing a trip to the work place. (ed) Nails: therapy, diagnosis, surgery, 2nd edn. Saunders, Acute hematomas should be evacuated when they Philadelphia, 1997; pp 282–300 are painful—often a hot needle or paper clip works 20. Wallis MS, Bowen WR, Guin JD. Pathogenesis of onycho- well [17]. Therapy for hydrofluoric acid burns is dis- schizia (lamellar dystrophy). J Am Acad Dermatol 1991; cussed above and should be performed by an experi- 24:44–48 enced practitioner [23]. Treating chronic paronychia 21. South DA, Farber EM. Urea ointment in the nonsurgical and onycholysis requires the elimination of the origi- avulsion of nail dystrophies—a reappraisal. Cutis 1980; nal irritant combined with an agent that treats the mi- 25:609–612 crobial agent topically or occasionally systemically. 22. Joseph WS. Podiatric approach to onychomycosis. In: Scher RK, Daniel CR (eds) Nails: therapy, diagnosis, surgery, 2nd edn. Saunders, Philadelphia, 1997; pp 301–310 References 23. Vance MV. Hydrofluoric acid burns. In: Adams RM (ed) Occupational skin disease, 3rd end. Saunders, Philadel- 1. Macaulay WI. Transverse ridging of the thumbnails. Arch phia, 1999; pp 13–15 Dermatol 1966; 93:421–423 24. Baran RL. Nail damage caused by weed killers and insecti- 2. Cohen PR, Scher RK. The nail in older individuals. In: cides. Arch Dermatol 1974; 110:467 Scher RK, Daniels CR (eds) Nails: therapy, diagnosis, 25. Ancona-Alayon A. Occupational koilonychia from organic surgery, 2nd edn. WB Saunders Co, Philadelphia, 1997; solvents. Contact Dermatitis 1975; 1:367–369 pp 127–150 26. Dawber R. Occupational koilonychias. Br J Dermatol 1974; 91:10 10 Irritant Contact Dermatitis of the Nails 93

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