Glucocorticoids are the most widely used drugs for the treatment of hypersensitivity, however these drugs themselves and the excipients contained in commercial corticosteroid formulations are able to induce severe immediate-type hypersensitivity reactions. Reactions involving excipients have been confirmed to be IgE mediated by the demonstration of specific-IgE to excipients such as carboxymethylcellulose and lactose. In case of hypersensitivity reactions to corticosteroid preparations, a complete allergy work-up with skin tests and/or challenge tests should include testing excipients as well as the active ingredients.