PA18 Pityriasis rotunda associated with glucose-6-phosphate deficiency in an adolescent boy

Abstract

Abstract Pityriasis rotunda is an uncommon disorder related to abnormal keratinization, which is characterized clinically by well-defined, scaly, round hypo- or hyperpigmented plaques present over the buttocks, thighs, trunk and lower limbs. It is thought to be a form of acquired ichthyosis. Two types of pityriasis rotunda are often described: type 1, which typically presents in Black and Asian patients > 60 years of age, and is often associated with systemic disease or malignancy; and type 2, which typically presents in patients < 40 years and without associated systemic disease, and may have a familial component. Pityriasis rotunda is particularly rare in children, although case reports have been published in the literature. We present an unusual case of pityriasis rotunda presenting in a 13-year-old boy of Ghanaian descent, with no significant family history. Examination demonstrated typical discrete, hyperpigmented, oval-shaped plaques appearing on the lower limbs and thighs. Biopsy demonstrated typical orthokeratosis, an attenuated granular layer and hyperpigmentation of basal keratinocytes. He was subsequently diagnosed with glucose-6-phosphate dehydrogenase deficiency, which is reported to be associated with pityriasis rotunda. This represents a rare case of pityriasis rotunda presenting in childhood, and may support an association with glucose-6-phosphate dehydrogenase deficiency.