Summary

This case of genital ulceration and social concerns in a preschool aged child was highly suspicious for child sexual abuse. However, the lesions presumed to be herpes simplex did not respond to antiviral medication. Specialist input from paediatric oncology and endocrinology resulted in a rare diagnosis of langerhans cell histiocytosis. Furthermore, the complication of diabetes insipidus later developed, making this the youngest child described to our knowledge with vulval lesions of langerhans cell histiocytosis and a central nervous system complication.