Erythema multiforme following pneumococcal vaccination.

Erythema multiforme (EM) is an acute and usually self-limited immune-mediated mucocutaneous disorder that is a hypersensitivity reaction to drugs, infections, and vaccines. Clinically, it is characterized by maculopapular, target-like lesions symmetrically distributed on the extremities (minor form) or additionally affecting one or more mucous membranes and causing epidermal detachment involving < 10% of the total body surface area (major form). We report a novel association between pneumococcal vaccination and the development of EM in a 2.5-year-old boy. The introduction of 13-valent-polysaccharide-pneumococcal-conjugate vaccine (PCV13) into vaccination programs has resulted in a reduced incidence of pneumococcal disorders. Systemic side effects of PCV13 include chills, fever, headache, vomiting, fatigue, arthralgia, myalgias, decreased appetite, and diarrhea, whereas its cutaneous adverse reactions are local injection site reactions, Sweet's syndrome, and deep morphea. EM is triggered by a variety of vaccines; however, as far as we know, it has not previously been reported in association with pneumococcal vaccine. Although a fortuitous occurrence of EM in our patient cannot be absolutely excluded, it appears very likely that PCV13 caused the patient's eruption, considering the history and the laboratory data, which point toward a lack of any other causative factors.