Cutaneous granulomas associated with vaccine-derived and wild type rubella virus
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Key takeaways:
- Estimated prevalence of rubella granulomas in patients with inborn errors of immunity is 0.6% to 2.4%.
- Rubella virus may impact not only immunodeficient patients, but also immunocompetent patients.
Clinicians should consider rubella virus as a potential contributor to granulomatous skin disease in both immunodeficient and immunocompetent patients, according to a study.
“Awareness of this entity is crucial to expanding our understanding of how vaccine-derived and wild type [rubella virus (RuV)] may impact immunodeficient and immunocompetent hosts,” Bridget E. Shields, MD, assistant professor in the department of dermatology at the University of Wisconsin, told Healio. “Our review highlights the importance of contributing RuV granuloma cases to CDC surveillance efforts to monitor transmission.”
According to the study, vaccine-derived RuV was found in the skin biopsies of granulomas in 60% of patients with inborn errors of immunity (IEI). These lesions are now referred to as RuV granulomas. Further, idiopathic granuloma prevalence in IEI patients is estimated at 1% to 4%.
Because of its recent discovery, RuV granuloma incidence and prevalence is still unknown; however, researchers estimate that the prevalence in IEI patients is 0.6% to 2.4%. As a result, there should be increased suspicion among IEI patients with idiopathic cutaneous granulomas, according to the study.
There is no standard for diagnosis in this indication, and symptom onset can span from 3 weeks to decades. This presents a diagnostic challenge, the researchers wrote.
Nevertheless, dermatologists should watch for asymptomatic, pruritic or tender lesions that may appear as pink erythematous to violaceous papules and plaques, especially surrounding the site of vaccination on the upper arm.
To confirm the diagnosis, a molecular testing of a skin biopsy is required, according to the study. In the United States, only the CDC can perform this testing, which includes reverse-transcription polymerase chain reaction for RuV and immunohistochemical staining for RuV capsid antigen.
RuV granulomas are extremely treatment resistant, according to the study.
“If RuV granulomas are identified, we still do not understand transmissibility risk as not all patients are shedding live virus,” Shields said. “We feel strongly that the benefits of MMR vaccination greatly outweigh the risk of vaccine-derived RuV granulomas in most patients.”