Discussion
Leukocytoclastic vasculitis is a small-vessel vasculitis characterized by immune complex deposition in the walls of dermal capillaries and venules. LCV commonly presents as erythematous macules with palpable purpura bilaterally, often in the lower extremities. LCV has previously been associated with vaccines, including vaccinations to influenza and herpes zoster.2-4
MMR vaccine-induced LCV in adults, accompanied with conjunctival injection has rarely been described. Typically, the MMR vaccine is indicated for children and adults born before 1957.5With the recent COVID-19 pandemic, more adults are receiving the MMR vaccine as it may induce innate immune responses that provide protection against COVID-19 infection via decreased production of pro-inflammatory cytokines.6
While the MMR vaccine rarely results in serious adverse effects, it has been associated with fever, transient rashes, transient lymphadenopathy, and parotitis in certain cases.5 Additionally, subtypes of leukocytoclastic vasculitis in children, such as Henoch-Schonlein purpura and acute hemorrhagic edema of infancy have been reported following MMR vaccine.7,8 There is one case report of a patient who developed LCV on her upper extremities and uveitis associated with MMR vaccination.9
Given that lenalidomide can also cause LCV, the history of recent vaccination was important for this patient to be treated appropriately.10 Had his oncologist not known about the recent MMR vaccination, it is likely that the treatment of his multiple myeloma would have been postponed or altered. In this case, it is unlikely that lenalidomide triggered the patient’s vasculitis given that the patient has continued to receive lenalidomide without recurrence of the rash.  Moreover, the patient had a longstanding prior history of lenalidomide therapy without any occurrence of LCV.
This is an interesting presentation of LCV occurring only on the upper extremities with associated conjunctivitis. As more adults are receiving the vaccine during the COVID-19 pandemic, it is important for clinicians to be aware of potential side effects to treat them promptly and properly.