Dry skin and blistering in childhood

A 5-year-old boy presented with a history of dry scaly skin. He had been born at term, with no collodion membrane or erythroderma noted at delivery. Skin changes were noted soon after birth, with widespread dryness and occasional blistering, mainly affecting the toes. Previous treatment with emollients and topical corticosteroids had not resulted in improvement. There was no family history of dermatological disease, and his parents were not related. Physical examination revealed mild, light-grey hyperkeratosis, particularly on the extensor aspects of the skin overlying the joints and the dorsal surfaces of the feet. In addition, superficially denuded areas with collarette-like borders (known as the Mauserung phenomenon) were seen, most notably on the knees (Fig. 1a–c). The palms, soles, head and neck were spared, and the hair and all nails were normal.