A Case of Tinea Incognito, Biopsy Result

Tinea corporis is a dermatophyte infection affecting the body surfaces with exception of the feet, groin, face, scalp hair or beard hair. It generally appears as annular or circular erythematous scaly lesions with elevated borders and central sparing. It is transmitted from one person to another or one site to another via fomites. Tinea incognito, a term first coined by Ive and Marks, is a dermatophyte infection that presents with an atypical appearance owing to modification from previous topical immunosuppressive therapy [1,2].  Microscopy and cultures are useful for diagnosis and usually topical or systemic antifungals may be sufficinet for treatment [2]. Recently litrature suggested occurence of T. indotineae which causes inflammatory and itchy, often widespread, dermatophytosis affecting the groins, gluteal region, trunk, and face which make it difficult to differentiate the two in resource limited centers [3].

A 24 year-old female attended our hospital with a widespread rashes involving the trunk and extremities, The condition started on the thigh 6 months prior her visit, the lesions were very itchy which non specific. She was diagnosed as dermatitis and given topical Betamethazone 0.1%, terbinafine tablet, fluconazole tablet, and weekly ultraviolet UV exposure on different occasion. Over the course of treatment the eruption spread extensively to her back, legs, buttocks, arms and began to develop scales and crust. The patient had family history of similar lesion from her mother and live in warm and humid climate. At our Hospital cliniacally she had multiple well deined scaly patches and Plaques with raise borders containing pustules and centeral clearence (Figure 1). They are located on both arms, buttocks, legs, and back, sparing the groin and face.  We had Differential diagnosis of Tinea Incognitor, chronic eczema, and other form of lupus erythematosus. A punch biopsy result suggested presence of dermatophyte infection on the keratin. A diagnosis of Tinea Imcognitor  was made. Itraconazole 200 mg capsules once daily for 4 weeks and miconazole 2% cream were prescribed. The skin lesions improved remarkable 1 week after the treatment (Figures 2&3). 

 Figure 1: Multiple Well Defined Scaly Erythematous Patches on buttock and left arm.

Figure 2: Arm of the Patient Showing Post-Inflammatory Hyperpigmentation after using Oral Iitraconazole Capsules for 1 Weeks.

Figure 3: Pathology result with PAS stain.

Tinea incognito, which represents approximately 40 % of tinea infections, is a term ascribed to a dermatophyte infection with atypical appearance resulting from previous immunosuppressive treatment such as steroids, topical tacrolimus, or pimecrolimus [2-5].Tinea incognito often presents a diagnostic challenge for clinicians because  may mimic other dermatological conditions such lupus erythematosus, rosacea, and contact dermatitis [6,7]. Our patient used topical corticosteroid therapy for more 6 months which made it difficult to make diagnosis which necessitate the biopsy and a PAS stain confirmed numerous fungal organisms in the upper keratin layers and this is the common method of diagnosing tinea corporis [8]. 

Other risk factors for atypical presentation are the host’s innate physiology and acquired host factors such as poor hygiene and unsanitary conditions same as in our patient who live in warm and humid climate which might contributed to the atypical appearance of patient’s eruption [1,9-11]. 

Virulence of an organism and its invasive capacity has been discussed much in recent studies especially the occurrence of resistant T. indotineae, which involve the gluteal region, buttocks and face has impacted management² and widely spread worldwide. Report suggested the resistance of T. indotinea  was initially diagnosed clinically as dermatophytosis which does not respond to treatment and worsens despite adequate oral antifungal therapy (Terbinafine). Our patient has typical presentation on the buttocks with face and groin not involved, despite interaction with Indian community which thought to be the origin of T. Indotineae, we were unabale to determine presence of T. Indotineae due to unavailability of fungal culture at our setting.

We believe many cases of tinea incognito were observed in our setting, and with the current evolution of resistant trichophyton spp in dermatophytes infection, it is unclear whether this was due to recurrent use of over counter medications or the new trichophyton infection that is resistant to most antifungal medications has reached the east African population, more efforts are needed to identify the culprit organism and control over-the-counter medications to control dermatophyte infection.

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