A 46-year-old man taking hydrochlorothiazide presents with a rash

Hypersensitivity vasculitis or leukocytoclastic vasculitis is the most common cutaneous small-vessel necrotizing vasculitis. Prodromal symptoms are typical for inflammatory disease and include fever, malaise, myalgia, and joint pain. The rash is defined as palpable purpura. The palpable petechiae of leukocytoclastic vasculitis usually begin on the lower legs and spread upward, covering the entire body in severe cases. Bright red pinpoint petechiae progress to violaceous 2-10 mm papules with distinct margins, often with a central pinpoint hemorrhagic vesicle or dark necrotic area**. Lesions usually appear in crops, lasting 1-4 weeks but heal with residual scarring characterized by hyperpigmentation. Older lesions are darker, often with a central pinpoint hemorrhagic vesicle or dark infarct. Palpable purpuric papules may vesiculate. The rash is not pruritic.**

Drug and viral triggers are associated with single isolated episodes, while systemic disease, such as rheumatoid arthritis and systemic lupus erythematosus, is associated with multiple recurrent episodes. Multiorgan angiitis is a possible outcome when it is associated with chronic inflammatory states.

Removing the offending agent is often the only treatment necessary because spontaneous clearing frequently occurs. Steroids can be used in more stubborn cases and NSAIDs can be used for secondary inflammatory symptoms. Colchicine has been used with success for cutaneous manifestations in chronic cases.

Follow this link to a more in depth synopsis of leukocytoplastic vasculitis.

Follow the following links to multiple images of leukocytoplastic vasculitis.

• Leukocytoclastic Vasculitis
• Leukocytoclastic Vasculitis (Palpable Purpura) #1
• Leukocytoclastic Vasculitis (Palpable Purpura) #2
• Leukocytoclastic Vasculitis with Palpable Purpura
• Leukocytoclastic Vasculitis with Hemorrhagic Vesicles and Bullae
• Leukocytoclastic Vasculitis with Necrotic Ulcerations

References: Habif TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 5th ed. Philadelphia, PA: Mosby Elsevier; 2010.