Vaccine-induced aluminium allergy and long-lasting subcutaneous itching nodules

Background: Aluminium contact dermatitis is rare even though aluminium is frequently used in antiperspirants and sunscreens. Sensitisation to aluminium is mostly a side effect of aluminium-adsorbed vaccines. These can also induce long-lasting intensely itching subcutaneous nodules (granulomas) at the injection site. During clinical trials on an acellular aluminium-adsorbed pertussis vaccine in the 1990s in Gothenburg, Sweden, persistent itching nodules were -unexpectedly- reported in 745 of ~ 76 000 vaccinated. Contact dermatitis to aluminium was verified by patch test in 377 children with itching nodules. Aim: This thesis aims to study the long-term clinical prognosis of itching subcutaneous nodules and aluminium allergy in children who received an aluminium-adsorbed pertussis vaccine in a clinical trial. Patients and Methods: All 745 vaccinated children with itching nodules in the pertussis vaccine trial were enrolled in a long-term follow-up study (>20 years). Results: The median duration of itching was 6.6 years. During the follow-up time 637/745 (86%) of the participants experienced full symptom recovery. The remaining were markedly improved. In 186 of 241 (77%) children who were tested twice, aluminium hypersensitisation was no longer detectable. A negative patch test was significantly correlated with loss of itching. 3-7% of the participants who received other aluminium-adsorbed vaccines later in life reported mild and transient itching at the new injection site. The optimal compound to establish aluminium hypersensitivity could not be determined. Conclusion and recommendations: Vaccine-induced subcutaneous itching nodules associated with aluminium allergy in infants and children can cause great suffering and have a protracted course. However, long-term prospective studies5 show that both clinical symptoms and delayed hypersensitivity for aluminium disappear over time. Further vaccination with aluminium-adsorbed vaccines is safe in older children given that the original nodule has vanished and the itching will have resolved or nearly resolved