Conference Coverage

Skin reactions after COVID-19 vaccination have six patterns


Skin manifestations of COVID-19 were among the topics presented in several sessions at the 49th Congress of the Spanish Academy of Dermatology and Venereology. Specialists agreed that fewer skin changes associated with this virus have been seen with the latest variants of SARS-CoV-2. They highlighted the results of the most remarkable research on this topic that were presented in this forum.

In the study, which was carried out by Spanish dermatologists with the support of the AEDV, researchers analyzed skin reactions associated with the COVID-19 vaccine.

Study author Cristina Galván, MD, a dermatologist at the University Hospital of Móstoles, Madrid, said, “This is the first study that analyzes a significant number of cases assessed by dermatologists and illustrated with clinical images of the dermatological manifestations caused as a reaction to these vaccines.”

The study was carried out during the first months of COVID-19 vaccination, Dr. Galván told this news organization. It was proposed as a continuation of a COVID skin study that was published in the British Journal of Dermatology. That study documented the first classification of skin lesions associated with COVID-19. Dr. Galván is the lead author of the latter study.

“The objectives of this study were to characterize and classify skin reactions after vaccination, identify their chronology, and analyze the associations with a series of antecedents: dermatological and allergic diseases, previous SARS-CoV-2 infection, and skin reactions associated with COVID-19,” said Dr. Galván. The study was a team effort, she added.

“It was conducted between Feb. 15 and May 12, 2021, and information was gathered on 405 reactions that appeared during the 21 days after any dose of the COVID-19 vaccines approved at that time in Spain: the Pfizer/BioNTech, Moderna, and University of Oxford/AstraZeneca vaccines,” she added.

Dr. Galván explained that the study shows very clear patterns and investigators reached conclusions that match those of other groups that have investigated this topic. “Six reaction patterns were described according to their frequency. The first is the ‘COVID-19 arm,’ which consists of a local reaction at the injection site and occurs almost exclusively in women and in 70% of cases after inoculation with the Moderna serum. It is a manifestation that resolves well and does not always recur in subsequent doses. More than half are of delayed onset: biopsied patients show signs of a delayed hypersensitivity reaction. In line with all the publications in this regard, it was found that this reaction is not a reason to skip or delay a dose.”

Herpes zoster reactivation

The second pattern is urticarial, which, according to the specialist, occurs with equal frequency after the administration of all vaccines and is well controlled with antihistamines. “This is a very nonspecific pattern, which does not prevent it from still being frequent. It was not associated with drug intake.

“The morbilliform pattern is more frequent after the Pfizer/BioNTech and AstraZeneca vaccines. It affects the trunk and extremities, and up to a quarter of the cases required systemic corticosteroids. The papulovesicular and pityriasis rosea–like patterns are equally frequent in all vaccines. The latter is found in a younger age group. Finally, there is the purpuric pattern, more localized in the extremities and more frequent after the Pfizer/BioNTech and AstraZeneca vaccines. On biopsy, this pattern showed small-vessel vasculitis.”

Less frequently, reactivations or de novo onset of different dermatologic diseases were found. “Varicella-zoster virus reactivations were observed with a frequency of 13.8%, being more common after the Pfizer/BioNTech vaccine,” said Dr. Galván. “Other studies have corroborated this increase in herpes zoster, although it has been seen that the absolute number is low, so the benefits of the vaccine outweigh this eventual complication. At the same time and along the same lines, vaccination against herpes zoster is recommended for those over 50 years of age.”

Another fact revealed by the study is that these reactions were not significantly more severe in people with dermatologic diseases, those with previous infection, or those with skin manifestation associated with COVID-19.

Dr. Galván highlighted that, except for the COVID-19 arm, these patterns were among those associated with the disease, “which supports [the idea] that it does not demonstrate that the host’s immune reaction to the infection was playing a role.”


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