Food allergies are divided into 2 main categories: IgE-mediated and non-IgE-mediated food allergies. Both forms can have significant health effects but differ in mechanism, symptoms, and management. The manifestation of the 2 forms differs between children and adults. These differences can be observed in the prevalence and the type of most common allergens and clinical presentation. The prevalence of food allergies has increased worldwide in recent decades. IgE-mediated allergies are the best researched and documented. They are particularly common in children, while non-IgE-mediated allergies are less well understood and diagnosed, leading to uncertainty about their prevalence. They often manifest as gastrointestinal symptoms that can occur hours to days after ingestion and are often difficult to distinguish from other food intolerances. The occurrence of food allergies varies significantly geographically. Differences in dietary habits, food composition, and environmental factors can partly explain these differences. There are also indications that genetics may play a role. IgE-mediated and non-IgE-mediated food allergies represent a significant and growing challenge for the global healthcare system. This article provides an in-depth review of both types of food allergy, discussing their potential causes, diagnostic possibilities, and available therapeutic strategies. Some diseases represent a mixed form of IgE and non-IgE-mediated immunological adverse reactions. Eosinophilic oesophagitis is the most common eosinophilic disease, and the diagnosis and treatment options are explained in more detail below.