Pityriasis rubra pilaris triggered by vaccination.

INTRODUCTION

Pityriasis rubra pilaris (PRP) is a rare inflammatory papulo-squamous skin disease. To date, the exact etiopathogenesis of PRP is unknown; although the most accepted triggers are viral or bacterial infections, few cases after vaccination have been reported as well.

EVIDENCE ACQUISITION: Our aim is to conduct a systematic review of cases of PRP triggered by vaccination. The PubMed and Scopus databases were searched for articles concerning PRP post-vaccination, published between January 2000 and June 2024. We also added a previously unpublished case that came to our attention.

EVIDENCE SYNTHESIS: Twenty-three articles were included, and 30 cases have been identified. The majority of patients were male (20/30, 66.6%). The median age of onset was 55 years (min 17 months-max 85 years). Most patients (27/30, 90%) were adults vaccinated against SARS-CoV-2, of whom 14/27 (51.9%) received mRNA-based vaccines (9 Comirnaty/Pfizer and 5 Spikevax/Moderna). The three pediatric cases had been vaccinated against Measles-Mumps-Rubella (2 cases) and intramuscular diphtheria-tetanus-pertussis vaccine plus oral poliovirus. The temporal relationship between vaccination and PRP onset varied (median 10 days post-vaccination; min 2-max 30). PRP occurred both after the first dose (14/30, 46.6%) and at subsequent doses of the vaccine. The majority of patients re-exposed to new doses (6/9, 66%) experienced clinical exacerbation. Post-vaccination PRP responds well to both traditional and biologic treatments, with only 4/30 (13.3%) showing no resolution.

CONCLUSIONS

In conclusion, PRP post-vaccination is rare and likely underdiagnosed, but recognizing the association is important to evaluate any new exposures to the trigger. A thorough patient history, including recent vaccinations, is crucial.