Aluminium-induced granulomas after inaccurate intradermal hyposensitization injections of aluminium-adsorbed depot preparations

Background: The development of persistent subcutaneous nodules at the injec tion sites of aluminium-adsorbed hyposensitization solutions is rare. These nodules have been interpreted as a delayed, granulomatous hypersensitivity reaction to aluminium. We report for the first time a case of persistent i ntradermal granulomas that developed at the sites of inaccurate intradermal , instead of subcutaneous, hyposensitization injections. Methods: An intradermal nodule was excised and processed for histopathology , scanning electron microscopy, and X-ray microanalysis. Intradermal and pa tch tests with aluminium hydroxide were performed. Results: Histologically, the nodule presented a pattern of granulomatous in flammatory reaction surrounding foci of necrotic tissue. Scanning electron microscopy and X-ray microanalysis revealed deposits of aluminium within th e granulomas. Patch tests with aluminium hydroxide were negative, and intra dermal tests caused persistent intradermal granulomas. Subsequent hyposensi tization therapy in our department with the usual subcutaneous injections o f aluminium-adsorbed allergen extracts was well tolerated by the patient. Conclusions: Local toxic effects of aluminium may be crucial in the develop ment of persistent intradermal injection-site granulomas. Such intradermal nodules may develop even if the subcutaneous route is well tolerated. We co nclude that inaccurate intradermal injections of aluminium-containing solut ions have to be strictly avoided.