Aluminium contact allergy without vaccination granulomas: A systematic review and meta-analysis

Aluminium contact allergy is mainly seen as granulomas following immunization with aluminium-adsorbed vaccines and contact allergy following epicutaneous exposure may be overlooked. To investigate the prevalence of aluminium allergy confirmed by patch testing, with no association with vaccination granulomas, and explore whether epicutaneous exposure to aluminium can contribute to allergic contact dermatitis. Two authors independently searched PubMed and MEDLINE (OVID) for case studies on contact allergy to aluminium proven by patch testing. Age-stratified meta-analyses to calculate the pooled prevalence were performed. Twenty-five studies describing a total of 73 cases were included in the review. Seven studies were suitable for meta-analyses. The prevalence of aluminium contact allergy was 5.61% (95% confidence interval [CI] 0.12%-11.08%) for children and 0.36% (95% CI 0.04%-0.67%) for adults. The studies described a variety of epicutaneous exposures, where metallic aluminium, topical medicaments, and deodorants were the main sources. Aluminium sensitization without a known exposure source was described in 10 of the 25 articles. The prevalence of aluminium contact allergy in the general public may be higher than expected and not solely related to vaccination granulomas. However, the clinical relevance is rare if not related to granulomas.