Hypersensitivity reactions to aluminium are very rate. Sensitization has been reported to occur during continuous application of aluminium-containing antiperspirants or by aluminium adjuvants in vaccines and hyposensitization immunotherapy. We report 5 patients who developed persistent and itching subcutaneous nodules following immunotherapy. Histologically, the nodules showed a granulomatous reaction consistent with delayed hypersensitivity to aluminium. Patch tests with 2% aluminium chloride in water were positive in three patients, and positive results of patch test with other metals (nickel, cobalt) were frequently associated.