Made susceptible, or immuno-reactive, to an antigen.
Becoming more sensitive, especially to bacteria or proteins that can trigger an allergic response, is a growing concern for doctors. This issue arises when topical agents containing certain medications, like antibiotics, are used to treat skin conditions. Sometimes, this sensitizes the patient to that specific drug. Consequently, if the same drug is administered later to address an internal ailment, the patient may immediately display a severe reaction, such as skin rashes. This reaction forces the doctor to discontinue the treatment. It is increasingly recognized that drugs used for topical treatment should be chosen carefully, as they might need to be used internally in the future. Sensitizing a patient to a drug in this manner can make its use in treatment impractical or even risky.