Yogurt-induced pruritus ani in a child

Abstract

Sir: An 8-year-old boy presented with pruritus ani from \vhich he had suffered intermittently, later continuously, over an 8 month period. The symptom responded neither to topical anti­ fungal and steroid creams nor to antihelminthics which were administered despite negative testing for pinworms. Zinc oxide cream had a soothing effect. Clinically, the perianal region was markedly reddened. The child had mild asthma but no other clinical abnormalities. The mother recalled that the onset of the complaints coin­ cided with the introduction of a daily cup of plain yogurt (pH 3.9). Before that he was drinking milk which was discon­ tinued because of recurrent abdominal pain. All signs and symptoms disappeared upon discontinuing the yogurt but reap­ peared upon its reintroduction. Pruritus ani is a vexing condition that is difficult to treat. On an anectodal basis it ha~ been linked to the ingestion of milk products, coffee, tea, chocolate and tomatoes [1]. Our observation suggests that yogurt may cause pruritus ani. The pathomechanism is unknown. It could be a direct ef­ fect of the offending food on the perianal environment or may represent an allergic reaction.