Allergic contact dermatitis from the vehicle components of topical pharmaceutical products.

The local application of pharmaceutical products may induce skin adverse reactions, including allergic contact dermatitis. Indeed, pharmaceutical products are, in general, applied on diseased or inflamed skin, the barrier function of which is often incapacitated, leading to enhanced skin penetration of the applied chemicals. Under these circumstances, even weak allergens are in such cases able to induce sensitization. The contact allergens in topical pharmaceutical products concern active principles and vehicle components, the latter of which are discussed in this article.