The Journal of the Arkansas Medical Society Med Journal March 2020 Final 2 - Page 20

Derm Dilemma Special Section: Short Dermatological Cases by Sam Schach, Biomedical Engineering Student, U of VA. Tinea Faciei A 23-month-old girl presents with a six- week history of worsening, erythema- tous, annular, and scaling plaques of the face. The patient’s mother applied an over-the-counter anti-fun- gal cream for three days without res- olution. They then visited their pedia- trician, who prescribed triamcinolone 0.025% cream. The patient’s mother has been applying the cream twice a day for four weeks. The rash has con- tinued to spread. mount depicted is positive which indicates a fungal infection. This proves the diagnosis to be tinea faciei. Granuloma annulare (GA) A common mantra in dermatology is “if it scales, scrape it.” When a scaling rash is seen and tinea is a possibility, a skin scraping for a KOH test is taken from the scale on the leading edge of the advancing border of the rash. The KOH test is used to determine if the rash is fungal in origin. KOH dissolves keratinocyte skin cells in order to bet- ter expose the dermatophyte hyphae for microscopic diagnosis. Early or less severe cases of tinea may be managed with topical antifungals whereas more severe or widespread cases are best treated with oral antifungals. When treated appropriately, tinea faciei typi- cally resolves without scarring. Provided this clinical image and photomicrograph of a potassium hy- droxide (KOH) mount, what is the most appropriate next step in management of this patient? A) The KOH test is negative. A skin bi- opsy should be taken and autoim- mune serologies should be drawn, as this patient most likely suffers from neonatal lupus erythemato- sus. Evaluate the mother for auto- antibodies and the child for heart block. B) The KOH test is positive. The patient has tinea faciei. The triamcinolone should be discontinued, and oral antifungal therapy initiated. Answer: B. has a predilection for the extensor surfaces of the joints, rarely presents on the face, and does not have surface scale. Neonatal lupus has a similar clinical appearance but pres- ents at birth or within the first few weeks of life. In nearly every case of neonatal lupus, the mother is found to have autoantibodies of the Ro/La family. Children with neonatal LE are at high risk for developing heart block and should be followed closely. The rash of peri- oral dermatitis is not annular and would have a negative KOH result. However, like tinea fa- ciei, perioral dermatitis is worsened by using topical corticosteroids. Although erythematous annular plaques are characteristic of granuloma annulare and neonatal lupus erythematosus, the KOH When dermatophyte fungal infection oc- curs on the face, it is called tinea faciei. Most commonly, the fungus will be the anthropo- C) The KOH test is equivocal. Given the fail- ure of the mid-potency corticosteroid, a stronger, Class 1 topical corticosteroid, should be prescribed, as the patient like- ly suffers from granuloma annulare. D) The KOH test is positive. This patient suffers from perioral dermatitis. Discon- tinue the use of triamcinolone and begin oral erythromycin and topical metroni- dazole cream. 212 • The Journal of the Arkansas Medical Society philic organism, Trichophyton rubrum. When history shows the patient had contact with other species, especially kittens or cats, Mi- crosporum canis is the zoophilic or- ganism that should be considered. The distinguishing characteristics of tinea faciei are spreading, erythematous, scaling, annular plaques with a posi- tive KOH test.