Persistent Subcutaneous Nodules and Aluminium Sensitization: Literature Review and Case Series Report

The development of persistent subcutaneous nodules at vaccination or hyposensitization injection site is a rare and under-reported event. These lesions have been attributed to the aluminium salts used as adjuvants. Patch testing on patients with the aforementioned clinical manifestations have yielded high sensitization rates to aluminium. It is believed this delayed hypersensitivity is the apparent cause of these reactive lesions in the dermis and subcutaneous tissue. In addition, aluminium hypersensitivity may cause contact dermatitis and gingivitis since it can be found in toothpaste and deodorants. We describe a series of 4 patients who developed SN at the injection site of vaccines and/or hyposensitization therapy, who underwent ultrasonography and patch testing for diagnostic confirmation. Patient management usually consists of potent topical steroids, antihistaminics, emollients and aluminium-containing products avoidance.