Pityriasis rubra pilaris after vaccination

Background. Pityriasis rubra pilaris (PRP) following vaccination is rarely described in the literature. We report a case of PRP occurring two weeks after measles-mumps-rubella (MMR) vaccination. Case report. - A 17-month-old infant was referred for a rash appearing two weeks previously. The child was presenting diffuse erythematous scaly exanthema with follicular papules and orange palmoplantar keratoderma. The clinical features were highly evocative of PRP. The histology was non-specific, displaying epidermal acanthosis with a regular and thick parakeratosis, and without any impairment of the follicular infundibulum. An MMR vaccination had been given two weeks before onset of the rash. Treatment with topical corticosteroids and emollients proved effective. Discussion. - Post-vaccinal PRP is rarely described in the literature. We report only the 3rd case. The first case concerned a 32-year-old woman presenting two episodes of PRP 10 days after diphtheria-tetanus-polio vaccination. The second case concerned a 47-year-old woman presenting PRP 18 days after anti-influenza vaccination and requiring treatment with acitretin. No cases have been described with MMR. These three vaccines (DTP, Tetragrip (R) and ROR) have no shared pharmacological constituents, and the trigger mechanism could be immunological or parainfectious. Conclusion. - Questioning about recent vaccination during history taking appears necessary to assess the importance of this trigger factor as well as the mechanism responsible for the onset of PRP. (C) 2011 Elsevier Masson SAS. All rights reserved.