Kerion

A 38-year-old man sought treatment for the intensely pruritic swellings that had arisen on his upper lip 2 weeks earlier (A). These sharply demarcated, tender, boggy, granulomatous, pustular tumefactions are kerions, write Florence Isaac, MD, of Mohammad Dossary Hospital in Saudi Arabia and Shaun Isaac, MD, of St Petersburg, Fla. The diagnosis is based on the history of acute onset, the clinical appearance of the lesions, and the demonstration of a fungus by a potassium hydroxide (KOH) preparation of loose hairs removed from the affected area and by fungal culture. In this case, the KOH preparation revealed fungal filaments, which on culture grew Microsporum canis. A pus swab test should be performed to detect any bacterial copathogen. The differential diagnosis of kerion includes impetigo and carbuncle.

Treatment with a combination of appropriate antibiotics, prednisolone, and griseofulvin or ketoconazole generally results in rapid resolution and keeps atrophy and permanent hair loss to a minimum. The oral administration of a saturated solution of potassium iodide has also been recommended for the treatment of patients with a kerion.

This patient was treated with erythromycin (500 mg 3 times a day for 5 days); oral prednisolone (20 mg/d), which was tapered over 3 weeks; and ultramicronized griseofulvin (700 mg/d for 6 weeks). In addition, topical ketoconazole cream was applied. Complete involution occurred after 6 weeks of griseofulvin therapy (B). *