Insulin allergy is a rare entity, complex to manage. Several types of hypersensitivity reaction are described, depending on the allergens (insulin itself vs additives). Type I, so-called immediate, IgE-mediated reactions are the most common. Their management requires a careful history and examination, as well as an allergological consult. If an IgE-mediated allergy is confirmed, insulin avoidance is recommended whenever possible. If insulin treatment is mandatory, another type of insulin may be offered. In case of failure, desensitization should be discussed, either via a dedicated protocol, or via insulin pump. In this article, we summarize the available data from the literature.