Paradoxical Reaction During a Course of Terbinafine Treatment ofTrichophyton interdigitaleInfection in a Child

Report of a Case | A child weighing 30 kg and without any comorbidities and allergies and not taking any long-term medications was seen for erythematous, infiltrating, welldemarcated skin lesions located on the face, chest, abdomen, and limbs (Figure, A). Mycological culture yielded growth of Trichophyton mentagrophytes. The fungus was identified as T interdigitale by sequence analysis of the internal transcribed spacer and the D1/D2 domains of the large-subunit (26S) rRNA gene within the rDNA cluster using the polymerase chain reaction sequencing described elsewhere.1 The patient reported frequent contact with stray cats. Initial treatment included 125 mg of terbinafine once daily. Twelve hours after the first dose, we observed temperature elevation (39°C), chills, malaise, aggravation of inflammatory symptoms including increased erythema, edema, and pustule formation (Figure, B). These changes were accompanied by increased erythrocyte sedimentation rate (47 mm/h), elevated C-reactive protein levels (25.8 mg/L), leukocytosis (white blood cell count, 15 390/uL), eosinophilia (eosinophils, 11%), and high IgE level (7200 μg/L). (To convert C-reactive protein to nanomoles per liter, multiply by 9.524; white blood cells to ×109/L, multiply by 0.001; and IgE to milligrams per liter, multiply by 0.001.) Therapy with terbinafine was discontinued for 3 days and oral prednisone was administered (10 mg/d). Terbinafine therapy was reintroduced at the same dose (125 mg/d) for 6 weeks resulting in a complete resolution of skin lesions.