Test your diagnostic skills in our regular dermatology quiz. What is the cause of this boy’s verrucous periungual lesions and red facial lesions?
A 13-year-old boy presents with verrucous periungual lesions on his toes, which have been treated with cryotherapy on three occasions without success (Figure 1a). He also has some small red lesions scattered over his face that his mother mentions have been unresponsive to acne treatment (Figure 1b). The boy is otherwise well, but he has had learning difficulties at school.