Tinea manuum might be asymptomatic, or patients can complain of thickened skin or pruritis. Infection is usually unilateral, but it can also affect both hands. The dorsum of the hand will show a similar morphology as in tinea corporis, characterized by a red plaque with an active vesicular and scaly border and a centrifugal growth. Several concentric rings might be seen (fig 1) (fig 2). Palmar surfaces usually have a dry, scaling appearance (fig 3).[16]

The most common clinical presentation is an entity known as “two-foot, one hand syndrome.” In this case, both feet are affected, and one hand presents with scaly patches or moderate to severe, diffuse dryness. In some patients, onychomycosis can be present in the same hand or even in both hands.[17][10]

Zoophilic dermatophyte infections must be suspected when inflammatory lesions with pustular or vesicular plaques on a highly erythematous base are seen, especially if the lesions are localized to one hand. Patients can describe pain, itch, and swelling, and rare cases might include local lymphangitis.[4][18]

Once a detailed medical history and clinical inspection suggest tinea manuum, mycological confirmation must be obtained. Some authors suggest that the gold standard for detecting a fungal infection must be a triple confirmation that includes: clinical exam, KOH, and culture.[18]

• Direct microscopy is a simple and inexpensive method to find the presence of fungal hyphae. Classically, a swab of pustular or wet inflammatory lesions or a scraping of dry, scaly lesions might be the first step. Nail clippings should be included if the onychomycosis is also suspected.[16] Usually, the specimen must be treated with potassium hydroxide (KOH), and the results are back within 24 hours in most of the laboratories. The sensitivity and specificity of KOH smears are 73.3% and 48%, respectively, so the smear should be complemented with culture. Cultures usually take 2-6 weeks to grow, so treatment should not be delayed while waiting for results. When available, antifungal susceptibility testing should be added to the culture to determine fungal susceptibility to terbinafine, itraconazole, and fluconazole.

• Fluorescent staining with optical brighteners might be used to increase the fungal detection rate. This stain selectively bids to chitin of the fungal cell wall and then gives an apple-green fluorescence when visualized under fluorescent microscopy.

• Histopathology might be necessary, especially when other skin diseases are suspected in the differential diagnosis.

• Dermoscopy has also been described recently as a useful and non-invasive tool that could assist in the diagnosis of tinea manuum. Typical localization and distribution of the scales in the furrows and dermatoglyphics seem to be unique to this entity.[19][20]

Other methods of dermatophyte differentiation, such as PCR, real-time PCR, and newer molecular methods, are being used in large institutions and for research purposes.[15]

Several topical and systemic antifungal therapy options and regimens are available. When possible, topical therapy is preferred for tinea manuum due to the risk of drug interactions and side effects of the oral treatments.

• There is no difference in cure rates among allylamines (terbinafine, naftifine), imidazoles (clotrimazole, fluconazole, itraconazole, ketoconazole), or other antifungals, such as butenafine and ciclopirox olamine.

• Regimens last 4 to 6 weeks, except for newer options like luliconazole and econazole (Ecoza, Spectazole), which usually require about 2 to 4 weeks of treatment.

• In addition, the anti-inflammatory effects (e.g., bifonazole) and the antibacterial properties [e.g., clotrimazole (gram-positive and gram-negative cocci) and isoconazole (gram-positive bacteria, including MRSA)] of several topical antifungals give specific value when choosing the agent.[15][21][22] While nystatin is effective for candida, it is not appropriate for dermatophytes; therefore, it should not be used to treat tinea manuum.

• Indications for systemic antifungals in tinea manuum include a co-infection of the nails, the involvement of two or more body areas, including the “two-foot, one-hand syndrome,” immunosuppression, recurrence of the infection, and topical therapy failure.[13] The oral options are terbinafine and itraconazole with similar rates of cure.[23][24]

• The use of corticosteroids is controversial; however, they can be beneficial in severely inflamed cases to reduce pruritus or burning sensations and, in some patients, to secure treatment adherence. When used, corticosteroid treatment should be administered with the antifungal therapy simultaneously, but it should be limited to only the first week of antifungal treatment.[25]

The differential diagnosis for tinea manuum includes various cutaneous diseases as well as bacterial, viral, and other fungal infections.

Psoriasis: usually bilateral and hyperkeratotic with thickened palms and soles. Patches of unaffected skin are commonly seen, and vesicular lesions, ungual pitting, and oil drop sign also can be found.

Dyshidrotic eczema: characterized by vesicles in the edges of the fingers, toes, palms, and soles that are very pruriginous and may be related to stress or seasonal allergies.

Contact dermatitis: irritant and allergic varieties are an inflammatory condition with erythematous and pruritic skin lesions that can affect palms and dorsum of hands, usually bilateral. The patient might describe that skin lesions occur after contact with a foreign substance, e.g., poison ivy or nickel.[2]

Inflammatory, bullous dermatophyte infections can be misdiagnosed as herpetic whitlow of herpes simplex infection, bacterial bullous impetigo, or cellulitis.[26][27]

Making the correct diagnosis and gaining compliance with an appropriate treatment regimen is critical to effecting a mycological cure. Some treatments might require several weeks, so noncompliance is a common reason for treatment failure.

Relapse or recurrence after therapy remains a concern. Infection transmission from symptom-free carriers, like family and pets, needs to be identified. Adjuvant therapies might be required for adequate control of infection in the treatment-refractory patient and in the carriers, and disinfectant techniques should be employed to control exposure via fomites.[12][28]

In general, most complications are due to delays in consultation and diagnosis. Medical evaluation sometimes occurs as late as months to years after the skin lesion appears.

Secondary bacterial infection and lymphangitis have been described in cases of inflammatory tinea manuum, especially in those due to a zoonotic dermatophyte.[6]

Contact dermatitis due to topical imidazole antimycotic therapy has been described as a rare complication of its use.[29]

A case of disuse contractures of the flexor tendons has been reported in a patient with tinea manuum and irritant contact dermatitis.[7]

Primary care physicians/providers will usually make the diagnosis and establish treatment; however, some cases can be challenging and might require a referral to a dermatologist and/or to an infectious disease specialist, especially in chronic or recurrent cases or for patients in whom underlying skin disease is suspected.

Education of patients must focus on:

Hygiene: wash hands more frequently to help remove pathogens on the surface of the hands.[10]

Avoid scratching the feet or touching onychomycosis.

Treat tinea pedis in time to prevent it from spreading from the feet to the hands.

Identify and treat possible contacts.

Encourage treatment compliance and avoid self-treatment with topical corticosteroids and antibiotics. These additional and often unnecessary treatments can delay the correct diagnosis.[3]

• When “hand eczema” is localized to one hand, consider fungal infection in the differential.

• If tinea manuum is confirmed, the feet must be examined, as the most common presentation of tinea manuum is “two feet and one hand.”

• Chronic treatment of a refractory hand dermatosis with topical corticosteroids or calcineurin inhibitors [e.g., pimecrolimus (Elidel), tacrolimus (Protopic)] might impede the correct diagnosis, i.e., “tinea incognito.”

• Exotic pet owners might develop inflammatory, bullous tinea manuum (usually caused by zoophilic dermatophytes) that can be misdiagnosed as bacterial or viral infections.

• Molecular biology dermatophyte diagnostics using nucleic amplification techniques have become an important part of the dermatophyte infection diagnosis.

Early diagnosis and treatment are essential in decreasing morbidity and facilitating manual function. Primary care providers should be able to treat most cases of tinea manuum; however, if there is an uncertain diagnosis or an inadequate response to therapy, the patient should be referred to a dermatologist. A referral is also prudent if immunodeficiency is suspected or diagnosed as a predisposing factor in the development of tinea manuum.