Striking but benign: acute haemorrhagic oedema of infancy

Abstract

A previously healthy 6-month-old boy presented in September, 2014, with indurated and tender oedema of the left hand, associated with a rapidly spreading purpuric rash on the dorsum. He also had swelling of one side of his face, but examination was otherwise normal. Beginning 4 days previously he had had a 3-day upper respiratory tract infection, with no associated fever; his parents denied trauma or previous drug use. Blood tests including full blood count, coagulation studies, and circulating immune complexes were normal, apart from moderate thrombocytosis (platelets 518 × 109/L; normal range 168–392 × 109/L) and normochromic normocytic anaemia (haemoglobin 99 g/L; 105–135 g/L). Urinalysis was normal. We diagnosed acute haemorrhagic oedema of infancy, a leukoclastic small-vessel vasculitis that was initially thought to be a benign variant of Henoch-Schonlein purpura, but is now considered a distinct entity. Acute haemorrhagic oedema of infancy typically aff ects children between 4 and 24 months of age, whereas Henoch-Schonlein purpura is more common in children aged 3 to 6 years. Unlike Henoch-Schonlein purpura, systemic involvement is rare in acute haemorrhagic oedema of infancy; symptoms are usually restricted to the skin. Cutaneous lesions are typically large nummular red or purpuric plaques or cockade-like lesions involving the face, ears, and limbs, but sparing the trunk and mucosa. Non-pitting oedema is more frequently noted on the arms and legs but can involve the face. In Henoch-Schonlein purpura the legs and buttocks are more commonly aff ected. Patients with acute haemorrhagic oedema of infancy usually look clinically well. Lesions usually resolve within 1–3 weeks without treatment. Long-term sequelae have not been reported. In our patient, the purpuric rash resolved within 4 weeks and at follow-up 6 months later he had had no further symptoms. After excluding infectious, immune, or infl ammatory causes of purpuric rashes, physicians should consider this rare, striking but benign diagnosis when faced with a well-appearing infant with purpuric plaques and non-pitting oedema.