Question:

An 18-year old girl presented with non-pruritic maculopapular rash on the extensor surfaces of her upper and lower limbs. The small petechial lesions coalesced into red-brown patches in the next 3 to 4 days.

She was initially admitted 1 week earlier due to left subclavian deep vein thrombosis. Heparin was started at the beginning but was switched to warfarin 2 days before onset of the rashes. She was afebrile and non-toxic. Laboratory tests were negative for thrombocytopenia and electrolyte disturbances. All cultures were also negative.

Answer: B. Warfarin-induced leukocytoclastic vasculitis

Leucocytoclastic vasculitis (LCV) is a vasculitic disease with protean manifestations. It usually presents as palpable purpura without coexisting thrombocytopenia. Some patients may also present with localized haemorrhage, vesicles, nodular lesions and superficial infarctions. Most of the time, these lesions are symptomless, but it may occasionally associate with itching or burning sensations. Drug induced, including warfarin, LCV is the most common cause.

Skin biopsy was performed on this patient, which revealed confluent epidermal necrosis associated with perivascular infiltration of neutrophils and formation of nuclear dust (leukocytoclasis), extravasation of erythrocytes, and fibrinoid necrosis of the dermal blood vessels.

Warfarin was discontinued and the patient did not develop any more new lesions. All of her lesions have subsided at her 6 weeks follow up.