No abstract

Onychomycosis is a fungal nail infection caused primarily by dermatophytes. Several other nail disorders, including psoriasis, can simulate onychomycosis. Accurate diagnosis is therefore vital for the ongoing treatment and management of onychomycosis and to avoid misdiagnosis and treatment delay, which can be both lengthy and costly. Often, a combination of histologic and laboratory techniques is used to obtain an accurate diagnosis. The potential diagnostic challenges associated with the differential diagnosis of onychomycosis caused by dermatophytes and the most common techniques used to confirm the diagnosis are discussed.

Onychomycosis is a fungal infection, and, as such, one of the goals of treatment should be eradication of the infective agent. Despite this, in contrast to dermatologists, many podiatric physicians do not include antifungals in their onychomycosis treatment plans. Before initiating treatment, confirmation of mycologic status via laboratory testing (eg, microscopy with potassium hydroxide preparation, histopathology with periodic acid-Schiff staining, fungal culture, and polymerase chain reaction) is important; however, more podiatric physicians rely solely on clinical signs than do dermatologists. These dissimilarities may be due, in part, to differences between specialties in training, reimbursement patterns, or practice orientation, and to explore these differences further, a joint podiatric medicine-dermatology roundtable was convened. In addition, treatment options have been limited owing to safety concerns with available oral antifungals and relatively low efficacy with previously available topical treatments. Recently approved topical treatments-efinaconzole and tavaborole-offer additional options for patients with mild-to-moderate disease. Debridement alone has no effect on mycologic status, and it is recommended that it be used in combination with an oral or topical antifungal. There is little to no clinical evidence to support the use of lasers or over-the-counter treatments for onychomycosis. After a patient has achieved cure (absence of clinical signs or absence of fungus with minimal clinical signs), lifestyle and hygiene measures, prophylactic/maintenance treatment, and proactive treatment for tinea pedis, including in family members, may help maintain this status.

Treatment of coexisting tinea pedis in patients with onychomycosis enhances the efficacy of once-daily topical treatment with efinaconazole topical solution, 10%.

Acral lentiginous melanoma (ALM) is a disease that is found on the palms, soles, and nail beds. Because these areas are not often examined during general medical examinations, the presence of ALM often goes unnoticed or the diagnosis is delayed. Research shows that the misdiagnosis of ALM is common, reported between 20% and 34%. We present three cases of ALM that were initially misdiagnosed and referred to the senior author (B.C.M.) in an effort to assess why misdiagnosis is common. The existing literature illuminates clinical pitfalls in diagnosing ALM. The differential diagnosis of many different podiatric skin and nail disorders should include ALM. Although making the correct diagnosis is essential, the prognosis is affected by the duration of the disease and level of invasiveness. Unfortunately, most of the reported misdiagnosed cases are of a later stage and worse prognosis. This review highlights that foot and ankle specialists should meet suspect lesions with a heightened index of suspicion and perform biopsy when acral nonhealing wounds and/or lesions are nonresponsive to treatment.