Terra Firma-Forme Dermatosis or Dermatosis Neglecta: A Diagnostic Continuum Illustrated by a Pediatric Case of Post-circumcision Penile Allodynia.

Terra firma-forme dermatosis (TFFD) and dermatosis neglecta (DN) can look identical on the skin, both presenting as dirt-like, verrucous plaques that clear with 70% alcohol swabbing. In both conditions, the plaque consists of retained, loosely adherent keratin and debris overlying otherwise normal skin, rather than a true structural epidermal lesion, which is why alcohol removes it. Classically, TFFD persists despite proper washing, whereas DN clears once hygiene resumes; alcohol swabbing does not distinguish between the two. We report a 13-year-old boy with probable autism spectrum disorder who developed a dirt-like, verrucous plaque on the penile shaft after circumcision, where persistent hyperesthesia (increased cutaneous sensitivity) and allodynia (pain provoked by a stimulus that would not normally be painful) made washing painful. Biopsy showed orthokeratotic hyperkeratosis with a normal dermis, ruling out a verrucous epidermal hamartoma. Rubbing the plaque with 70% alcohol produced complete clearance, ruling out a fixed lesion. No findings suggestive of caregiver neglect were identified; the avoidance was localized and self-directed. Hygiene was subsequently discussed with the patient and his caregiver in light of his pain threshold and sensory sensitivities, and he was referred for neuropsychiatric follow-up. This case highlights an underrecognized cutaneous complication of pediatric circumcision, where pain avoidance combined with neurodevelopmental vulnerability can mimic a primary keratinization disorder.