Stephen J. Krivda

An outbreak of urticaria among soldiers deploying for combat

An outbreak of urticaria among soldiers deploying for combat Dear Sir, Before deploying overseas, American military personnel receive a battery of vaccinations specific for their destination. Rabies human diploid cell vaccine (HDCV), Imovax® (Aventis Pasteur, Strasbourg, France), is administered to certain troops en route to Africa and Asia where rabies is common in feral animals and the troops do not have ready access to health care. Although adverse reactions to rabies HDCV are uncommon, 1 we report an outbreak of rabies HDCV-associated urticaria in a unit deploying for combat. A 42-year-old man developed generalized pruritus with scattered edematous red wheals over his trunk and swelling of his right upper eyelid. He had received the second immunization in the series of the rabies HDCV 14 days earlier. On examination, he was noted to have clearly defined blanching, edematous, red plaques with no evidence of petechiae, purpura, peripheral edema or lymphadenopathy. He denied fevers or arthralgias. We examined 12 additional men who over the previous few days had presented to medical personnel with similar complaints. The interval from receiving the HDCV immunization to the onset was urticaria was 5–15 days. Six patients received treatment with oral antihistamines with or without prednisone and all cases resolved without sequelae. We recently investigated an outbreak of urticaria in 13 soldiers at a processing center for overseas deployment. The 13 men all shared the common cutaneous finding of urticaria. These 13, along with 305 other soldiers in their group, had received a booster dose of the rabies HDCV or the second or third doses in the 3-dose pre-exposure series. The overall rate of urticaria was 4.3%. No other noteworthy adverse reactions were reported. The standard rabies vaccine series consists of three 1.0-ml intramuscular doses of rabies HDCV given on days 0, 7 and either 21 or 28. 2 The Advisory Committee on Immunization Practices recommends booster vaccination at 6 months or 2 years depending on the exposure risk and serologic status. Urticarial reactions to rabies HDCV occur more frequently after the booster rather than the primary immunization. 1 The reported incidence of urticaria in patients receiving the rabies HDCV ranges from 2 to 7%. 1,3 They are thought to represent a Type III hypersensitivity-mediated immune response rather than a Type 1 IgE-mediated event. 3 Skin biopsies from rabies HDCV-associated urticarial lesions often demonstrate a leukocytoclastic vasculitis with neutrophil and lymphocytic infiltrates; fibrin and C1q granular deposits may be found on direct immunofluorescence. 3 Although, histological findings support the presence of immune complex-mediated urticaria, there is no laboratory evidence (proteinuria, elevated creatinine or blood urea nitrogen) of renal or other systemic involvement. In this outbreak of HDCV-associated urticaria, none of the patients had clinical evidence of serum sickness; however, no laboratory investigations were performed. Because HDCV is rarely administered to large cohorts of individuals, an outbreak such as this one has not been reported previously.

Field-Based PCR for Rapid Diagnosis of Cutaneous Anthrax in the Deployed Setting Using the Joint Biological Agent Identification and Diagnostic System

Anthrax is occasionally encountered by U.S. military physicians in the deployed setting, where limited resources make it difficult to obtain laboratory confirmation. We present a case of cutaneous anthrax diagnosed using a ruggedized polymerase chain reaction device in austere combat conditions.