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A 34-year-old Hispanic woman is referred by her family practitioner for evaluation of a rash on her arms, legs, and abdomen. The clinician diagnosed the rash as allergic contact dermatitis, administered intramuscular triamcinolone, and placed her on an oral antihistamine. Over the following 6 weeks, the rash’s intensity waxed and waned. When the patient is first examined in the dermatology office, faded patches of the rash are noted. The rash is nonpruritic, and her routine blood testing is unremarkable. Other than oral antihistamines, the patient is not taking any medications. She shares an image of the rash during a severe flare-up (Figure).
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Leukocytoclastic vasculitis (LCV) is an inflammation of the small vessels. In approximately 50% of cases, the condition is idiopathic and may be triggered by medications, infections, or underlying malignancy.1 LCV may be accompanied by itching or burning, but many cases are asymptomatic.
Palpable purpura is the classic presentation. Lesions are typically round, distributed bilaterally, and often appear in crops. Definitive diagnosis is provided by biopsy that reveals neutrophil infiltration within small vessel walls accompanied by fibrinoid necrosis. Direct immunofluorescence is often positive.2
Most cases of idiopathic LCV are self-limiting. Lesions on the lower extremities often respond well to rest, compression, leg elevation, and antihistamines. If lesions are drug-induced, removal of the offending medication results in rapid clearance.3 Symptomatic and/or prolonged cases may respond to colchicine.4 Both oral and topical dapsone may induce resolution.5 Severe cases may require high-dose corticosteroids for adequate control.
Sara Mahmood, DPM, is a podiatric dermatology fellow at St Lukes University Health Network and DermDox Center for Dermatology. Stephen Schleicher, MD, is director of the DermDox Center for Dermatology in Pennsylvania, as well as an associate professor of medicine at Commonwealth Medical College and a clinical instructor of dermatology at Arcadia University and Kings College.
References
1. Takatu CM, Heringer APR, Aoki V, et al. Clinicopathologic correlation of 282 leukocytoclastic vasculitis cases in a tertiary hospital: a focus on direct immunofluorescence findings at the blood vessel wall. Immunol Res. 2017;65(1):395-401.
2. Grunwald MH, Avinoach I, Amichai B, Halevy S. Leukocytoclastic vasculitis—correlation between different histologic stages and direct immunofluorescence results. Int J Dermatol. 1997;36(5):349-352.
3. Ram D, Mathur S. Quetiapine-induced leukocytoclastic vasculitis. Indian J Pharmacol. 2019;51(4):282-283.
4. Sais G, Vidaller A, Jucglà A, Gallardo F, Peyrí J. Colchicine in the treatment of cutaneous leukocytoclastic vasculitis. Results of a prospective, randomized controlled trial. Arch Dermatol. 1995;131(12):1399-1402.
5. Pate DA, Johnson LS, Tarbox MB. Leukocytoclastic vasculitis resolution with topical dapsone. Cutis. 2017;99(6):426-428.
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