Case Presentation:
A 41‐year old man with DM type II and SLE not taking prescribed plaquenil, presented with painful rashes. These started 4 months ago as small purpuric papules that grew into large vesicles in the shoulders and ears (see figure). Patient reports using cocaine and heroin for the last 6 months. Examination showed multiple purpuric patches and bullae on the shoulders and ears, a discoid rash with ulcers on the left leg, and a malar rash. Laboratory data showed leukopenia, anemia, and negative urine toxicology. HIV testing and hepatitis serology were negative. As a lupus flair was suspected an autoimmune panel was sent: ANA positive, dsDNA: 110 (NL 0‐29), C4 complement 12 (NL 16‐47); steroids were started. Three months prior dsDNA levels were 70 with a normal C4. As the rash in the legs was different from the lesions in the shoulders, there was a high suspicion for concomitant vasculitis. Therefore, a proteinase‐3 Ab assay (PR‐3 or cANCA) was sent which came back positive. Skin biopsy of the shoulder showed acute thrombotic vasculitis with retiform purpura and ischemic bullous necrosis, consistent with cocaine‐induced vasculitis. The lesions markedly improved after a week of removal of the inciting agent and he was discharged on steroids for his leg rash, which was scheduled to be biopsied in the clinic. He was lost to follow‐up.
Discussion:
We present an interesting case of cocaine‐induced vasculitis (CIV) in a patient with preexisting SLE with skin manifestations. We faced a clinical challenge as our patient had serologic markers consistent with an SLE flare as well as positive PR‐3 Ab and skin biopsy for a distinct vasculitis. CIV is an increasingly recognized complication of cocaine use, which presents with a purpuric rash that has a predilection for the ears, positive ANCA and leukopenia. Antineutrophil Cytoplasmic Ab (ANCA) comes in two known forms, the cytoplasmic pattern against PR‐3 (cANCA) and the perinuclear florescence pattern. In CIV, an additional Ab to the human neutrophil elastase (HNE), structurally related to PR‐3, can be used for diagnosis. However, in our case this was not sent as the PR‐3 Ab and skin biopsy were sufficient for diagnosis. CIV has been associated with cocaine diluted with levamisole, an anti parasitic agent, which potentiates the development of the rash. There is an estimated 1.9 million cocaine users annually in the US. Up to 70% of the cocaine supply is contaminated with levamisole.
Conclusions:
Hospitalists need to be aware of CIV when seeing a purpuric rash, given the prevalence of cocaine use in the US and its frequent contamination with levamisole. As in our case, it’s crucial to discern this vasculitis from rashes that develop in some rheumatologic conditions as the immediate treatments and long‐term management differ.
