Nut Hypersensitivity: Allergic reaction to tree nuts that is triggered by the immune system.Nuts: Botanically, a type of single-seeded fruit in which the pericarp enclosing the seed is a hard woody shell. In common usage the term is used loosely for any hard, oil-rich kernel. Of those commonly eaten, only hazel, filbert, and chestnut are strictly nuts. Walnuts, pecans, almonds, and coconuts are really drupes. Brazil nuts, pistachios, macadamias, and cashews are really seeds with a hard shell derived from the testa rather than the pericarp.Hypersensitivity, Delayed: An increased reactivity to specific antigens mediated not by antibodies but by cells.Drug Hypersensitivity: Immunologically mediated adverse reactions to medicinal substances used legally or illegally.Hypersensitivity: Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.Areca: A plant genus of the family ARECACEAE. Members contain ARECOLINE and CATECHIN. The leaves and nuts have been used as masticatories, stimulants, and astringents in traditional medicine. The common name of betel is also used for PIPER BETLE. The common name of catechu is sometimes used for ACACIA CATECHU.Alveolitis, Extrinsic Allergic: A common interstitial lung disease caused by hypersensitivity reactions of PULMONARY ALVEOLI after inhalation of and sensitization to environmental antigens of microbial, animal, or chemical sources. The disease is characterized by lymphocytic alveolitis and granulomatous pneumonitis.Dermatitis, Contact: A type of acute or chronic skin reaction in which sensitivity is manifested by reactivity to materials or substances coming in contact with the skin. It may involve allergic or non-allergic mechanisms.