Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disorder. The role of hypersensitivity to food and inhalant antigens in the induction and maintenance of AD has remained an area of controversy. Making diagnosis of food allergy in AD patients is challenging, since there is no specific single diagnostic test. Patient`s clinical history and laboratory tests such as skin prick test, serum specific IgE, and atopy patch test are used for diagnosis. The final diagnosis is made by oral food challenge test. The fundamental principle in treatment of food allergy is avoiding the causative food in all forms. House dust mites and Cockroach are the most prevalent inhalant allergens. There are two possible routes in the sensitization of inhalant allergens which are transcutaneous, and respiratory route. The diagnosis of inhalant allergy can be made by positive skin test associated with serum specific IgE and atopy patch test. The main mite allergens are Der p1 and Der p2 which are from mite feces and bodies, respectively. In cockroach, antigenicity are stronger in the body or exuviae compared to its eggs or feces. Eradication of house dust mites and cockroach is important in the treatment of inhalant allergy as avoidance of the allergen is the mainstream of the treatment. Food allergy is common in infancy and early childhood AD patients and inhalant allergy is common in relatively older AD patients. It is important to consider food or inhalant allergy when managing intractable AD patients.