Allergic reactions or hypersensitivity reactions are an excessive response of the human immune system to a particular allergen, which might result in damage to normal tissues. Allergic reactions can occur by ingestion of various allergens such as food, inhalation of allergens (pollen), after insect bites, after contact with certain materials (latex), physical exertion and lastly, after the application of certain drugs. In this paper, the emphasis is on drug-induced allergic reactions. The division of allergic reactions into immediate and delayed reactions has been clarified with the presentation of specific symptoms for the listed reactions. Also, the classification of hypersensitivity reactions according to Gell and Coombs, developed nearly 50 years ago, and still used today, is beeing presented. Throughout history, several immunotherapeutic protocols have been developed that alter the immune response in various ways with certain efficiancy. One of these approaches is desensitization, which creates a temporary tolerance of the drug to a person with a drug allergy, thus enabling the safe use of the drug while respecting certain drug application protocols. To date, desensitization protocols have been developed and successfully applied for a number of antibiotics, antiviral, biological, nonsteroidal anti-inflammatory drugs, and chemotherapeutic agents. The desensitization procedure is performed equally successfully in adult patients as it is with children. The aim of this paper is to point out the advantages of the desensitization procedures and assignments of the nurse, which has a leading role in the desensitization process. Mentioned assignments of nurses in desensitizing adults are well described in the literature, but there is a lack of data on desensitizing procedures for children.