Two weeks after inoculation with the varicella virus vaccine (Varivax, Merck and Co., Inc., West Point, Pennsylvania), a 26-year-old healthy man who was seronegative for human immunodeficiency virus noticed a 2.0-cm oval-shaped macule on the skin of his left axilla. Ten days after onset of the eruption, about 50 such lesions were counted on the trunk, concentrated in the axillary regions (not at the vaccination site). The pink-red lesions were nonblanching and had a darker red border. The results of punch biopsy were nondiagnostic.

During the next 6 weeks, the macular lesions gradually faded as reddish, 1- to 2-mm petechiae developed in about the same distribution (Figure 1). These lesions spread over the trunk, neck, and extremities bilaterally, sparing the face, palms, soles, and oral mucosa. A 2-week course of 0.5% fluocinonide cream twice daily, started after 22 days, was ineffective. A complete blood count done 34 days after onset revealed a low platelet count (114 x 10⁹/L), slightly decreased hematocrit (0.393) and leukocyte count (3.7 x 10⁹/L), and normal differential.

View larger version (78K): [in this window] [in a new window]   Figure 1. Macular-petechial rash 4 weeks after the onset of a hypersensitivity reaction to the varicella virus vaccine.

A second skin biopsy done 29 days after onset showed hypersensitivity vasculitis. This biopsy specimen and the initial biopsy specimen tested negative for varicella-zoster virus DNA by polymerase chain reaction and in situ hybridization [1]. The eruption continued to spread until a regimen of rapidly tapering oral prednisone was started 36 days after onset. This therapy cleared the lesions within 1 week. The patient has remained lesion-free for more than a year and now demonstrates immunity to varicella-zoster virus (titer 1:8 by immunofluorescence assay).

These findings are consistent with hypersensitivity vasculitis due to the varicella vaccine as defined by the American College of Rheumatology [2, 3]. The absence of an abnormal blood urea nitrogen level, an abnormal serum creatinine level, proteinuria, or other clinical symptoms makes the diagnosis of a viscerocutaneous syndrome unlikely [4, 5]. Negative results on tests for rheumatoid factor, antinuclear antibodies, and cryoglobulin mitigated against an autoimmune cause. The patient was not taking any other medications during this period and has no history of reactions to gelatin or neomycin, which are contraindications for varicella virus vaccine administration.