Hypersensitivity/allergic reactions excipients

Allergic contact dermatitis from transdermal estrogen has been described in Korea, where the reaction was found to be due to 17-P-estradiol itself and not to an excipient (226). In some cases, allergic reactions and systemic contact dermatitis are clearly attributable to the patch material or to excipients. Even natural estradiol given in this way can occasionally cause hypersensitivity reactions, as determined by patch tests (227). 

A number of adverse reactions to mannitol have been reported, primarily following the therapeutic use of 20% w/v aqueous intravenous infusions.The quantity of mannitol used as an excipient is considerably less than that used therapeutically and is consequently associated with a lower incidence of adverse reactions. However, allergic, hypersensitive-type reactions may occur when mannitol is used as an excipient. 

Many of these studies involved application of copious amounts to animal skin or to human volunteers in Phase I studies. Others concerned reports of reactions in people suffering from pre-existing allergic conditions. Reports of side effects must, therefore, be viewed from such perspectives and the possibilities for side effects weighed against the widespread use of the same materials in food, confectionery, cosmetic, and household products as well as in medicines. This is not to belittle the hypersensitivity and other reported reactions but unless these are put into context, there may be further constraints on excipient usage and unrealistic demands for totally inert formulation adjuvants. 

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