CONGENITAL INSENSITIVITY TO PAIN PRESENTING AS DIGITAL NECROSIS

K. Neuling, H. Goodyear. Heart of England NHS Foundation Trust, Birmingham, UK

Introduction: Congenital insensitivity to pain is due to a number of inherited disorders that are associated with sensory and autonomic dysfunction. Herpetic whitlow is a herpes simplex virus type 1 or 2 infection of the fingers characterised by erythema and painful vesicles. It is a self-limiting condition in the immunocompetent individual and is not usually associated with necrosis or scarring. A 13-month-old boy who developed a gangrenous fingertip following presumed herpetic skin infection is presented.

Case report: He presented with a 1-month history of changes affecting the thumb and tip of the index finger that were black and necrotic. The history was one of vesicular lesions with surrounding erythema. There was also marked ulceration and oedema of the lower lip and tip of the tongue. He showed no signs of discomfort despite the dramatic skin changes. His parents had previously noted that he did not cry in response to falls or when he was immunised. He is the first child of consanguineous parents with no significant family history. His development is normal and he is felt to have normal sweating. Over a period of 2 weeks, the necrotic index finger tip auto-amputated. Other skin changes improved following intravenous aciclovir and antibiotics. Blood urate levels were normal. Neurophysiological studies showed no evidence of significant peripheral neuropathy. Congenital insensitivity to pain, hereditary sensory and autonomic neuropathy (HSAN), is considered the most likely diagnosis in this patient. His symptoms are not completely characteristic, however, of previously described types.

Conclusions: The diagnosis of HSAN is based on clinical features and the genetic defect varies according to type. It is important to think about underlying disorders in children, particularly when a child with normal immunity presents with unusually severe and destructive skin lesions. …