An intractable kerion celsi forming a scutulum due to Microsporum gypseum

Abstract

An 83-year-old female had been treated with immunosuppressive agents including glucocorticoid steroids for 20 years due to rheumatoid arthritis. She noticed hair loss and underwent a medical check at a nearby dermatological clinic. Her scalp lesions worsened and erythema with scale appeared on the back of her right hand after the use of a steroid ointment. Direct microscopic examination of individual hair roots and the scale from her scalp and hand showed the presence of fungal elements, and she was diagnosed with kerion celsi and tinea manus. Microsporum gypseum was identified by fungal culture. She started treatment with oral terbinafine at 125 mg/day ; however, her itching and tenderness worsened, and thick and yellowish scutula (so-called favosa) appeared on the scalp. The dose of terbinafine was increased to 250 mg/day, after which her symptoms got better, and she finally healed 5 months later. We thought that the patient may have been refractory to treatment with a standard dose of terbinafine, or even have developed favosa, because she was immunosuppressed due to her treatment for rheumatoid arthritis.