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Home , Amorolfine, Mycosis, Nail disease, Onychogryphosis, Onycholysis, Onychomycosis

MedicineToday 2014; 15(12): 40-44

PEER REVIEWED FEATURE 2 CPD POINTS

Nail disease Is it fungal and how should it be managed?

Key points KENG-EE THAI MB BS(Hons), BMedSci(Hons), FACD • is typically asymptomatic and Fungal accounts for about half of all abnormalities. subclinical, representing a Differential diagnoses include , and Pseudomonas cosmetic problem. infection. Treatment usually requires long-term continuous or pulsed • moulds are the most common cause. therapy. • Differential diagnoses that should be considered in ungal infection of the fingernail or toenail DERMATOPHYTE VS NONDERMATOPHYTE patients with nail plate is termed onychomycosis or tinea MOULDS abnormalities include unguium. It accounts for about one-third Most cases of onychomycosis are caused by psoriasis, lichen planus and of all fungal and half of all nail dermatophyte moulds. These fungi are Pseudomonas infection. F abnormalities. Onychomycosis has a prevalence ­ubi­quitous; they are found in almost any • Keeping the feet and of about 10%, varying geographically. The ­environment that can support their existence. toenails dry can help prevalence increases with age. It is mostly grow on keratinised tissues – prevent onychomycosis. asymptomatic and subclinical; patients present the ‘dead’ component of and its append- • Systemic agents have the only when affected by its clinical appearance. ages. The most common dermatophyte highest success rates in However, onychomycosis can be the source of infecting nails and skin is treating onychomycosis; dermatophytes that cause tinea on other parts rubrum. This anthropophilic organism has a they include , of the body. Treatment typically requires a worldwide distribution and is abundant in any and protracted course of an oral antifungal agent. moist, warm area frequented by humans. Other . This article outlines a practical approach to dermatophyte species can also affect the nail • Topical treatments are the management of onychomycosis. The phar- plate. Dermatophyte infections are typically typically useful only for macology of topical and oral antifungal agents easier to treat than nondermatophyte infec- superficial white used in was discussed in a previous tions, as most respond to oral antifungal onychomycosis and very article on dermatophyte infections, in the June preparations. mild subungual 2014 issue of Today.1 Saprophytic nondermatophyte moulds onychomycosis; they include , Dr Thai is a Consultant Dermatologist and Visiting Medical Officer at the Epicutaneous Patch Testing Clinic and , ciclopiroxCopyright and _Layoutand 1 Nail17/01/12 Clinic, Prince 1:43 PM of Wales Page Hospital, 4 Sydney; a Visiting Medical Officer at the Macquarie University Hospital,

. Sydney; and in private practice in Gordon, Sydney, NSW. © BODELL COMMUNICATIONS/PHOTOTAKE/DIOMEDIA.COM

40 MedicineToday x DECEMBER 2014, VOLUME 15, NUMBER 12 Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2014. Figure 2. Classic distal and lateral subungual onychomycosis involving multiple and finger nails. Note the yellow-green Figure 1. Superficial white onychomycosis, showing a powdery discolouration visible on the surface of the nail, representing tinea white infection of the superficial part of the nail plate of the in the nail plate and subungual , and of second toe. the fingernails, in contrast with the normal fingernail. can also infect the nail plate, albeit uncom- Distal and lateral subungual monly. Typically, these moulds do not grow onychomycosis on other keratinised tissues, such as the Distal and lateral subungual onychomycosis is skin. Scopulariopsis brevicaulis is the most the most common type of onychomycosis, with common nondermatophyte to infect the the infection gaining access via the distal free undamaged nail plate, whereas Acremonium, nail plate and extending proximally (Figure 2). and spp. can cause Yellow, brown or white discolouration of the superficial white onychomycosis. Infections nail plate occurs. The nail plate may thicken and with nondermatophyte moulds are often is lifted up by subungual hyperkeratosis as the more difficult to treat than dermatophyte infection moves upwards. Chards (streaks) of infections, especially if deep-seated; itracona- infection can be seen running up the nail plate. zole with or without nail plate avulsion is Eventually the nail plate can be completely required. involved and destroyed. Distal and lateral In addition, spp. can infect the nail ­subungual onychomycosis may start in the nail plate and associated nail fold. Infection can plate of one digit and extend to the others. take the form of and associated nail dystrophy or, more rarely, total nail plate Proximal subungual onychomycosis involvement and destruction in the setting of Proximal subungual onychomycosis is unusual, chronic mucocutaneous . where whitening of the nail starts proximally as the is able to access the nail plate via PRESENTATION the proximal nail fold. Proximal ­subungual There are several types of onychomycosis, based onychomycosis is more common in patients on the mechanism of infection and clinical who are immunosuppressed, such as in HIV appearance of the nail plate. infection. T. rubrum is the most common cause. Superficial white onychomycosis Superficial white onychomycosis describes a Endonyx onychomycosis very superficial infection, where the fungal Endonyx onychomycosis is a highly unusual elements are found on the surface of the nail variant, where the nail plate becomes second- plate. Powdery, white, circumscribed patches arily involved by an infection that begins in the are seen (Figure 1). This is typically caused by finger or toe pulp. Extension of the infection to Trichophyton interdigitaleCopyright. T. _Layoutrubrum 1 and 17/01/12 non- 1:43the PMnail Page plate 4 leads to nail pits, lamellar splits, dermatophytes can also be causative. subungual hyperkeratosis and onycholysis.

MedicineToday x DECEMBER 2014, VOLUME 15, NUMBER 12 41 Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2014. Fungal CONTINUED

Figure 3. Nail psoriasis Figure 4. showing subungual Pseudomonas hyperkeratosis, which is infection of the commonly misdiag­nosed nail plate as tinea. Note the absence showing a of the yellow-green streaks greenish expected in dermatophyte discolouration infection, and the presence that is not seen of the salmon-pink ‘oil in tinea. drop’ sign just proximal to the hyperkeratosis.

Endonyx onychomycosis is caused by fun- or nail destruction, although an accompa- INVESTIGATIONS FOR ONYCHOMYCOSIS gal species responsible for infec- nying chronic paronychia may lead to nail The ‘gold standard’ for the laboratory tion (infection of the substance of the hair plate distortion or dystrophy. diagnosis of onychomycosis is a positive shaft), such as Trichophyton soudanense. fungal culture of nail clippings. Although Lichen planus isolation of a fungus is diagnostic, culture DIFFERENTIAL DIAGNOSES Lichen planus is an inflammatory condi- is an insensitive test, and a negative result Although onychomycosis is exceedingly tion that leads to destruction of the nail does not rule out onychomycosis. When common and in most circumstances easy complex. The characteristic feature is a a nail specimen is harvested for micro­ to diagnose, several differential diagnoses pterygium. In the context of the nail appa- scopy and culture, the greater the volume should always be considered. It is also ratus, this is a scarring process in which of material submitted the greater the important to note that onychomycosis the proximal nail fold adheres to the nail chance of a positive culture. The soft, can be a secondary infection or coexist plate and is dragged along as the nail macerated subungual debris gives the with any other nail dystrophy. grows. The end product is a scarred nail greatest load of fungal elements. A small bed with no nail plate. (2 mm) bone or skin curette is useful for Psoriasis scraping underneath the nail plate. Psoriasis can cause nail dystrophy and Simple traumatic onycholysis Fungal elements can also be seen on discolouration, subungual hyperkeratosis Simple traumatic onycholysis is very com- histopathology of the nail plate and are and onycholysis. It can be very difficult mon. In the fingernails, this is caused by easily identified by the periodic acid-Schiff to differentiate clinically from onycho­ excessive wet work and hand washing, as stain. This method can have a much . However, features of psoriasis well as fastidious nail care where the higher positivity rate for diagnosis of that help in this differentiation include: patient cleans under the nail to remove onychomycosis, but the disadvantage is • a different quality of the dystrophic debris, inadvertently lifting the nail the lack of culture confirmation. nail, with less yellow discolouration ­further. The toenails can be lifted by exces- and no white/yellow streaks sive walking and exercise in tight shoes. PREVENTION • early involvement of multiple nails Scraping of the great toenail along the General measures • changes such as distinctive nail pits in ceiling of the toe box of the shoe can shear Dermatophytes are ubiquitous organ- a regular pattern the nail plate from the bed. Subungual isms found in the soil and on animals • the salmon pink ‘oil drop’ sign of hyperkeratosis, chards of infection and and humans. Thus patients can poten- ­subungual discolouration (Figure 3) discolouration are not seen, although sec- tially be infected from anywhere, and it • psoriasis present elsewhere on the ondary Pseudomonas infection may pro- is impossible to strictly avoid the fungi. skin. duce a green tinge. The key to preventing any fungal infec- tion is to deny the organisms favourable Pseudomonas infection conditions to flourish – that is, a warm, Pseudomonas infection should always be Onychogryphosis can affect elderly moist, protected environment. The feet considered in patients who do a lot of ‘wet patients and involves gross thickening of and toenails should be kept relatively work’. It leads to onycholysis with green the nail plate related to age and chronic dry. Open shoes are ideal, allowing the discolouration of theCopyright nails (Figure _Layout 4). There 1 17/01/12 trauma. 1:43 PM Tinea Page of the4 nail plate can often toe and webs to air dry. After a shower, is typically no subungual hyperkeratosis coexist with onychogryphosis. the feet and web spaces can be blow dried

42 MedicineToday x DECEMBER 2014, VOLUME 15, NUMBER 12 Downloaded for personal use only. No other uses permitted without permission. © MedicineToday 2014. with a hair dryer. People who must wear onychomycosis is not a major clinical prob- abnormal nail if mycological cure is closed shoes and socks for work should lem, and no treatment is also a legitimate achieved. If the chard of fungus grows choose styles that are more ventilated option. proximal to the scored line then treatment (e.g. fabric rather than leather construc- Systemic agents have higher success failure is likely. tion). Heavy safety boots can be venti- rates than topical agents in treating lated with grommets and perforations onychomycosis and are typically safe but, Terbinafine by a shoe maker. like all , may have side effects. Terbinafine is the most effective agent for Another practical approach is to sprin- Patients need to be happy to use a systemic dermatophyte onychomycosis. The stand- kle antifungal powder into shoes. This agent with its inherent risks to treat an ard dosing regimen for dermatophyte does not treat onychomycosis but may essentially cosmetic issue. infection is 250 mg daily for six weeks for prevent reinfection after the patient has As an alternative to systemic therapy, fingernail onychomycosis and 12 weeks received adequate therapy. Older shoes, superficial white onychomycosis and very for toenail disease. Multiple studies have which are likely to carry the fungus, mild cases of distal and lateral onychomy- shown the efficacy of this regimen, with should be replaced. Hot washing of socks cosis can be treated with topical agents. a short-term mycological cure rate of will reduce their fungal load. These act slowly and have significant failure about 76 to 78%.2 Wearing thongs or shoes in public rates. Patients should be reminded of the Another recommended approach is to amenities such as swimming pools and need to be persistent and regular in apply- ‘pulse’ the treatment, by giving 250 mg change rooms may help avoid gross con- ing topical therapy and also to observe for daily for one week every two to three tamination of the feet with detritus, but worsening onychomycosis, at which time months until the nail grows out. My pref- incidental contact with fungus-infested an oral agent may be considered. erence is to administer the daily for surfaces is almost unavoidable. Thorough The pharmacology of therapies for one week every month, until the nail grows washing and drying of the feet is impor- cutaneous fungal infections was discussed out to become normal. tant to prevent the fungus flourishing. in a previous article in the June issue of When to commence therapy is arbitrary. Medicine Today.1 PBS subsidisation is available for terbinaf- Predisposing factors ine if 80% of the great toenail is affected Predisposing factors for onychomycosis Systemic therapy and the infection has been mycologically include: The aim of treatment is a normal-looking confirmed. Regardless of the extent of • age-related changes in the toenails nail. It is important to recognise that ­disease, I find it more timely and efficient • mycological cure is not equivalent to to write a private script for terbinafine, as • HIV infection ­clinical cure. After the traditional three- the relative cost of the is not • peripheral vascular disease month course of an oral antifungal agent, prohibitive, and this avoids the requisite • peripheral neuropathies mycological cure is possible but the nail delay for cultures to be performed. Fur- • sporting activities may still look abnormal. Patients need to thermore, culture often gives false-negative • traumatic nail problems recognise that the nails grow slowly, and results, and repeated testing simply for PBS • pedal anatomical abnormalities. even if there is no active infection, the nail sub ­sidisation is undesirable. Good control of diabetes and peripheral plate may take many more months to grow vascular disease is likely to keep the skin out completely. Patients should be reas- Itraconazole of the feet in good condition and thus sured when the proximal portion of the Itraconazole is a relatively expensive agent reduce the risk of infection. Patients with affected nail appears normal and clear of when used for the treatment of onycho- diabetes, peripheral vascular disease or discolouration. mycosis. It is useful when: neuropathy should inspect their feet daily However, in practice, treatment failure • terbinafine is contraindicated for problems including onychomycosis and is common after the prescribed three- • the fungus is resistant to terbinafine, tinea to allow prompt treatment. However, month course. I consider it advisable to as determined by treatment failure, or onychomycosis is exceedingly common, continue treatment until the abnormal • a nondermatophyte mould is and clinicians should not equate its pres- nail grows out completely. Cost and expo- cultured. ence with any predisposing disease. sure to the drug can be minimised by a Itraconazole is given at a dose of pulsed regimen. A useful technique to 400 mg daily for one week each month TREATMENT monitor for treatment failure is for a line (seven doses each month). For mycological Both topical and systemic options are to be scored into the nail plate at the most cure of common dermatophyte tinea, two ­available for the treatmentCopyright _Layout of patients 1 17/01/12 proximal 1:43 PM portion Page 4of the visible infection. to three pulses are required for fingernails, with onychomycosis. In most cases, The line should move distally with the and three to four pulses for toenails. The

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short-term mycological cure rate is up to agent, as described below. REFERENCES 75%.2 My preference is to pulse the therapy • Amorolfine lacquer is used weekly until the nail grows out to become clini- after sanding down the nail with a 1. Thai K-E. Therapies for common cutaneous cally normal. nail file. ­fungal infections. Med Today 2014; 15(6): 35-47. Itraconazole is fat-soluble and is best • Bifonazole cream is applied after a 2. Gupta AK, Ryder JE, Johnson AM. Cumulative absorbed with a low pH environment in week of nail preparation with meta-analysis of systemic antifungal agents for the the stomach. If patients have relative cream to break down the treatment of onychomycosis. Br J Dermatol 2004; ­achlorhydria or cannot take the medication ­hyper­keratotic nail plate and allow 150: 537-544. with a main meal then an acidic drink (such removal by scraping. 3. Hollmig ST, Rahman Z, Henderson MT, Rotatori as a cola soft drink) is useful in improving • lacquer is applied directly RM, Gladstone H, Tang JY. Lack of efficacy with absorption. A new prepar­ation of itracona- to the nail surface, daily until cure, 1064-nm neodymium:yttrium-aluminum-garnet zole was recently released in Australia with with no nail preparation required. laser for the treatment of onychomycosis: a rand- twice the potency, requiring only half the • Miconazole tincture is applied omized, controlled trial. J Am Acad Dermatol 2014; dose to achieve the same efficacy as the directly to the nail surface until cure. 70: 911-917. pre-­existing preparation. Topical treatments may be useful for superficial white onychomycosis and very FURTHER READING Fluconazole mild subungual onychomycosis but have Fluconazole is another alternative to terbi- little role in well-established distal and DermnetNZ. http://dermnetnz.org/fungal/tinea.html nafine, although the mycological cure rate lateral subungual onychomycosis. (accessed December 2014). 2 is much lower at only about 50%. It is given Online. . The University as pulse therapy, with one dose per week Physical therapies of Adelaide. http://www. mycology.adelaide.edu.au/ for six months for fingernails and nine Occasionally, the thickened or dystrophic Mycoses/Cutaneous/Dermatophytosis (accessed months for toenails. Doses in the literature nail plate may be removed for cosmesis December 2014). range from 150 to 450 mg daily. My pref- or pain. Both surgical and chemical means UpToDate. Dermatophyte (tinea) infections. http:// erence is to balance cost with effectiveness, are available, and should be used in www.uptodate.com/contents/dermatophyte-­tinea- using the 200 mg tablets weekly until the ­conjunction with a systemic agent for infections (accessed December 2014). nails grow out completely normally. effective cure. Referral to a dermatologist with an interest in nails would be useful. COMPETING INTERESTS: None. Griseofulvin is the oldest oral antifungal Use of vascular lasers has been in available for onychomycosis. Being fung- vogue for the treatment of onychomyco- Online CPD Journal Program istatic rather than fungicidal, it is much sis. The initial enthusiasm for this treat- less effective than terbinafine or the . ment has waned significantly as practi- A dose of 0.5 to 1.0 mg daily is required tioners and patients found a low and for adults; 18 months of therapy may be inconsistent clearance rate.3 The mecha- required before complete clinical clearance nism of action appears to be thermal of onychomycosis. The other agents destruction of the fungal elements. How- ­discussed are more effective for treatment ever, patients are typically unable to of onychomycosis. ­tolerate the high temperature and dura- tion of treatment required for effective Topical therapy fungicidal effect. There are a number of topical nail kits currently available in Australia. Although CONCLUSION © SERHAD/DOLLAR PHOTO CLUB easily accessible by patients as over-­the- Onychomycosis is an exceedingly com- List three differential diagnoses for counter preparations, the cure rates from mon type of fungal infection that is best fungal nail disease. lengthy use of these agents are typically treated with a systemic agent. Oral terbi- Review your knowledge of this topic and poor, achieving a mycological cure rate nafine is the most effective. Clinical cure earn CPD/PDP points by taking part in ­of less than 50% and a clinical cure rate of is best achieved with an intermittent/ MedicineToday’s Online CPD Journal Program. less than 10%. These topical treatments pulsed r­ egimen until the affected nail has Log in to typically require physicalCopyright preparation _Layout 1 17/01/12of grown 1:43 out PM and Page been 4 replaced completely www.medicinetoday.com.au/cpd the nail to aid absorption of the active with a normal nail plate. MT

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