P362 Delayed type hypersensitivity reactions to aluminium-adsorbed vaccines: a case series

Persistent pruritic subcutaneous nodules have been reported at the site of vaccination (vaccination granulomas) following the use of several aluminium-adsorbed vaccines. An incidence of 0.8–0.9% has been reported in the literature. Contact allergy to aluminium has been strongly associated with the presence of vaccination granulomas. During the aluminium adsorbed diphtheria-tetanus/acellular pertussis vaccine trials, hypersensitivity to aluminium was demonstrated in 77% of those with pruritic nodules. These nodules appear to be long-lasting but little is known regarding prognosis. In this case series, we report twelve children who developed pruritic nodules at injection sites following vaccination and were referred to a tertiary paediatric Dermatology centre for assessment between 2010 and 2018. The median age at onset of symptoms was twelve (IQR: 6 – 19.5) months and the main presenting symptoms were pruritus in eight children (67%) and pain in three children. Six out of the seven children tested in the series for contact allergy for aluminium were positive (86%). One child was found to have developed cutaneous pseudolymphoma on biopsy, a potential adverse effect of vaccines containing aluminium hydroxide as an adjuvant. This is the first case described in a child following vaccination. Four of the eleven children had imaging studies, two of which were reported as venous malformations. Conclusion Although an infrequent occurrence following vaccination with aluminium-adsorbed vaccines, the development of persistent pruritic nodules can cause significant distress and anxiety for parents and children and lead to unnecessary investigations and a delay in subsequent vaccination. Greater awareness among clinicians and primary health care providers of this potential adverse reaction is necessary.