CHILD HEALTH / DERMATOLOGY TINEA INFECTION – AN ILLUSTRATED GUIDE

Tinea is an infection of keratinised tissues, including skin, hair, or nails, caused by a group of fungi known as dermatophytes. It is a common presentation in children and young people, but di

Pictures and Tinea may infect various parts of the body and is termed accordingly, eg: information courtesy of „ Tinea capitis (scalp) „ Tinea pedis (feet) „ Tinea unguium (nails) Timothy G „ Tinea corporis (body) „ Tinea manuum (hand) „ Tinea versicolor (trunk) Berger MD „ „ Source: The Tinea cruris (groin) Tinea faciale (face) Dermatology Glossary, Figure 2b: The lesions are often arranged in an UCSF School FIGURE 1: TINEA CAPITAS annular configuration and often have an elevated, of medicine serpiginous border

FIGURE 2: TINEA CORPORIS Figure 2a: Fungal infection of the skin that presents as FIGURE 3A: TINEA PEDIS (ATHLETE’S FOOT) well-defined, erythematous, scaling papules or Fungal infection of the feet that presents as plaques. scalingon the sole of the foot and scaling, maceration, bullae, vesicles,fissures, and erosions between the toes.

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Figure 3b: Bullous tinea pedis – showing The usual distribution for tinea versicolor is that presentation of bullae. Presentation of vesicles may of a short-sleeved turtleneck sweater – neck, trunk, also be seen in this condition upper arms. The responsible organism is the yeast Pityrosporum orbiculare (called Malassezia furfur when in the infectious hyphal form). Fungal enzymes produce compounds that inhibit melanin production. Often the lesions are asymptomatic and patients become aware of the lesions because affected areas do not tan. INVESTIGATIONS

FIGURE 6: POSTASSIUM HYDROXIDE PREPARATION A diagnostic test using potassium hydroxide (KOH) to diagnose a fungal infection of the skin.

FIGURE 4: TINEA UNGUIUM, SHOWING SEVERE DISCOLOURATION OF THE NAILS

The test involves vigorous scraping of scale from the edge of a scaling lesion. If vesicles or pustules are being tested, the underside of the vesicle is sampled. The scraping is deposited onto a glass slide and a drop of 10 to 20% KOH is added before covering with the cover slip. The undersurface of the slide is gently heated before microscopic examination. Under 100X magni!cation, the entire cover slip is scanned for the presence of hyphae which are thread-like branching tubular cells interconnected by septa. Microscopically, a KOH preparation shows a combination of fungal hyphae and yeast forms in a “spaghetti and meatballs” appearance within the super!cial layers of the epidermis. FIGURE 5: TINEA VERSICOLOR This shows infection of the skin at the stratum corneum that has caused pigmentary changes FIGURE 7: MICROSCOPY and scaling in the epidermis. The lesions appear as patches with fine scale and can be pink, tan, or most commonly, white.

Microscopically there are septate fungal hyphae in the super!cial layers of epidermis which are more easily demonstrated with PAS (periodic acid Schiff) stains that stain fungal hyphae walls. The epidermis may show hyperkeratosis with variable neutrophil in!ltrates and spongiosis. The dermis may have a mixed in"ammatory in!ltrate and tinea can cause subepidermal bulla Formation. Speciation of fungi is not reliable by simple microscopic methods and is not needed for therapy.

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