Applied Evidence N EW R ESEARCH F INDINGS T HAT A RE C HANGING C LINICAL P RACTICE Clear choices in managing epidermal tinea infections Brian Thomas, MD Medical Department, Commander Naval Coastal Warfare Group One Practice recommendations hough findings on history and physical examination are sometimes sufficient to ■ Potassium hydroxide preparation should T make a diagnosis of tinea infection, a be used as an aid to diagnosis for all potassium hydroxide (KOH) study usually is erythrosquamous lesions (B). required for confirmation. Even the KOH study ■ Fungal culture should be used in cases can be misleading, however, if a patient recently in which history, physical examination, and self-administered a topical antifungal agent. This potassium hydroxide preparation fail to article describes the varying appearance of tinea clearly exclude a diagnosis of tinea (B). infections according to their anatomic location, and outlines a careful work-up. ■ Short-duration topical therapy with Highly effective and affordable over-the- terbinafine, naftifine, and butenafine counter medications have proliferated, and is efficacious for most epidermal tinea short-course therapy is available. Based on infections (A). systematic reviews of randomized, controlled ■ Oral antifungal agents are important studies, it is possible to recommend specific in the treatment of tinea infections that first-line therapies for tinea infections. are widespread, fail to respond to topical treatment, involve the thick stratum ■ MANIFESTATIONS corneum of the soles and palms, or OF TINEA INFECTION occur in immunosuppressed patients. Clinical manifestations of tinea vary with anatomic ■ Short courses of oral itraconazole and location, duration of infection, and pathogen terbinafine are safe and effective in (see page 856). In general, zoophilic dermato- treating tinea infections (A). phytes evoke a more vigorous host response than the anthropophilic species.5 Shared features of many dermatophyte infections include erythema, scaling, pruritus, ring formation, and central clearing of lesions. Table 1 reviews published data on the diagnostic value of selected clinical signs in suspected tinea infection.6 Tinea pedis Correspondence: Brian Thomas, MD, NOLF-IB, Bldg 184, Box 357140, San Diego, Ca 92135. E-mail: Tinea of the foot may manifest as interdigital, [email protected]. plantar, or acute vesicular disease. Toe webs 850 NOVEMBER 2003 / VOL 52, NO 11 · The Journal of Family Practice MANAGING EPIDERMAL TINEA INFECTIONS AppliTABLE 1 Diagnostic value of selected signs and symptoms in tinea infection Sign/symptom Sensitivity Specificity PV+ PV– LR+ LR– Scaling 77% 20% 17% 80% 0.96 1.15 Erythema 69% 31% 18% 83% 1.00 1.00 Pruritus 54% 40% 16% 80% 0.90 1.15 Central clearing 42% 65% 20% 84% 1.20 0.89 Concentric rings 27% 80% 23% 84% 1.35 0.91 Maceration 27% 84% 26% 84% 1.69 0.87 Note: Signs and symptoms were compiled by 27 general practitioners prior to submission of skin for fungal culture. Specimens were taken from 148 consecutive patients with erythematosquamous lesions of glabrous skin. Culture results were considered the gold standard. PV+, positive predictive value; PV–, negative predictive value; LR+, positive likelihood ratio; LR–, negative likelihood ratio. Adapted from Lousbergh et al, Fam Pract 1999; 16:611–615.6 Level of evidence=2b. For an explanation of levels of evidence, see page 865. and soles of the feet are the sites most erythrasma by lack of bright coral appearance commonly affected. Tinea pedis occurs most when examined with a Wood’s lamp. Tinea pedis commonly in postpubertal adolescents and infections also lack the well-demarcated erosions, adults, but may be seen in children.7 or pits, of pitted keratolysis. Evidence of concur- With interdigital infection, toe webs may rent onychomycosis should increase the suspicion become scaly, pruritic, and fissured. Interaction that tinea pedis is the correct diagnosis. of bacteria and infecting dermatophytes may lead to a white, soggy maceration.8 Extension Tinea manuum from the web space to the dorsal or plantar Tinea of the hand is usually analogous to surface commonly occurs. moccasin-type tinea pedis. The palm appears In chronic plantar or moccasin-type tinea hyperkeratotic and has very fine white scale pedis, the entire surface of the sole may be that emphasizes the normal lines of the hand. covered with fine, white scale and may assume Tinea of the dorsal surface of the hand usually a hyperkeratotic appearance. Chronic web infec- occurs in the classic ringworm pattern. Tinea tion may lead to acute inflammation character- manuum is often seen in association with tinea ized by vesicles, pustules, and bullae over the pedis and onychomycosis. Many clinicians are sole or the dorsum of the foot.5 familiar with the “one hand, two feet” syndrome, Differential diagnosis. The differential diag- in which the palmar surfaces of both feet nosis includes dry skin, pitted keratolysis, and one hand are infected (Figure 1).9 erythrasma, and contact dermatitis. Some Onychomycosis often occurs in association with conditions may appear very similar to tinea this presentation of tinea. pedis, increasing the importance of KOH prep Differential diagnosis. The pattern of tinea and fungal culture. manuum may be confused with those of eczema, Tinea pedis may be distinguished from contact dermatitis, palmar psoriasis, or even NOVEMBER 2003 / VOL 52, NO 11 · The Journal of Family Practice 851 MANAGING EPIDERMAL TINEA INFECTIONS FIGURE 1 Tinea pedis FIGURE 2 Tinea corporis The common “1 hand, 2 feet” syndrome of tinea pedis. Widespread tinea corporis. This patient would not be a This syndrome usually requires systemic therapy. candidate for topical treatment. normal, rough hands. Unilateral involvement, ly develop a raised border and begin to spread presence of fingernail onychomycosis, lack of his- radially. As the ring expands, the central portion tory indicating irritant or allergen exposure, and of the lesion often clears. This pattern leads to the absence of psoriatic nail changes should increase formation of irregular circles that gives tinea cor- the suspicion of palmar tinea manuum. poris its common name, ringworm (Figure 2). Tinea faciale is less common, but generally Tinea cruris has a similar appearance with central clearing Tinea of the groin is most common in adult males of lesions. Tinea faciale may not always exhibit and is promoted by a warm, moist environment. the sharply demarcated border of tinea corporis. Tinea cruris begins in the crural fold and spreads Differential diagnosis. Eczema, impetigo, onto the thigh. The interior portion of the lesion is early pityriasis rosea, and localized psoriasis usually erythematous or slightly brown in light- can mimic tinea corporis. History of exposure to skinned individuals. The leading edge often persons or animals (typically house pets) with advances in a sharply demarcated semicircle with known ringworm should increase suspicion of a raised, slightly scaling border. The lesion is tinea corporis. Current or past evidence of most often bilateral, sparing the skin of the scro- psoriasis or eczema should broaden the differ- tum. Pruritus is common and increases as sweat ential to include atypical presentations of these macerates the irritated skin. diseases. Differential diagnosis. Candidiasis, intertri- go, and erythrasma can cause similar lesions. It ■ DIAGNOSING TINEA: HISTORY is helpful to recall that candidiasis may involve AND EXAM NOT ENOUGH the scrotum and penis while tinea cruris does so In some cases, findings on history and physical rarely. An additional helpful feature is the char- evaluation are so characteristic of tinea that acteristic bright coral appearance of erythrasma they alone may allow the clinician to make a when examined with a Wood’s lamp, absent in firm diagnosis. However, studies have shown cases of tinea cruris. that relying upon history and physical examina- tion may result in a many missed diagnoses.6 Tinea corporis and tinea faciale Accordingly, consider tinea in all instances of Tinea infections of the face and body begin as flat, papulosquamous skin disease and follow up scaly, and often pruritic macules that subsequent- appropriately. Figure 3 presents a simple 852 NOVEMBER 2003 / VOL 52, NO 11 · The Journal of Family Practice MANAGING EPIDERMAL TINEA INFECTIONS FIGURE 3 Evaluating possible tinea infection of the skin Patient's history and findings on physical exam suggest tinea infection. Treat with oral terbinafine or itraconazole. One week of therapy may suffice. Prepare KOH slide for (See text for details.) microscopic evaluation. YES Does microscopic exam reveal YES Is infection widespread or recurrent over palmar fungal hyphae typical of tinea? or plantar surfaces? Or is the patient immunosuppressed? NO NO YES Be sure the patient has not self-med- icated with an OTC antifungal agent. YES Arrange for fungal culture. Treat with topical Is your clinical suspicion terbinafine, naftifine, of tinea high? Is the result butenafine, or an azole positive? agent. (Terbinafine has NO proven superior to azoles and is available as inex- NO pensive OTC formulation.) If topical treatment fails to Consider alternative diagnoses yield acceptable clinical Fungal culture is highly (see text for details of differential). response, consider oral specific. Consider alterna- If treatment is unsuccessful, consider antifungal regimen tive diagnoses (see text for repeating KOH prep and arranging details of differential). for fungal culture. algorithm