[Retrospective analysis in children with vaccination granuloma].

Background: Vaccine granulomas are a common (0.3-1%) adverse event (AE) of (accidentally) subcutaneously administered vaccines and specific immunotherapies containing aluminum conjugates. The clinical symptoms with persistent itching subcutaneous nodules, predominantly affect infants and young children on the lateral thigh.

Aim: To sensitize dermatologists to recognize this common and harmless vaccination AE, in order to prevent invasive diagnostics and confusion among parents and physicians.

Materials and methods: Retrospective analysis of 13 children consulting pediatric dermatology between 2019 and 2023. Identification of diagnostic criteria and guidelines for action, based on the literature.

Results and conclusion: In all, 13 children (9 boys, 4 girls) with subcutaneous indolent but itching nodules at the vaccination sites (11 on the thighs, 2 on the upper arms) with a latency of weeks to months were retrospectively evaluated. The children were vaccinated according to German STIKO ("Ständige Impfkommission") recommendations. Only inactivated vaccines contain aluminum. The documented occurrence of the first vaccination granulomas was between the 12th and 36th month of life. Regarding the STIKO vaccination calendar, the third immunization with the hexavalent inactivated vaccine coincides with the first administration of the live measles, mumps and rubella (MMR) vaccine (varicella (V)). This may incorrectly lead to the assumption that the live vaccine was the cause of granuloma development. Aluminum conjugation appears to be a central trigger of the granulomas; further susceptibility factors are largely unknown. Diagnosis of sensitization to aluminum through epicutaneous testing has no practical impact and is, therefore, not routinely recommended. After weeks to years, granulomas spontaneously regress.