Amblyomma americanum mammalian meat and meat products. The allergy manifests as anaphylaxis — a life-threatening allergic reaction characterized by constriction of airways and a drop in blood pressure. This response is triggered by an IgE antibody to the mammalian oligosaccharide galactose-alpha-1,3-galactose (alpha-gal). As well as occurring in non-primate mammals, alpha-gal is also found in cat dander and in the drug cetuximab. Allergic reactions to alpha-gal usually occur 3–6 hours after consuming red meat, unlike allergic reactions to other foods, whose onset following consumption is more or less immediate, making it more difficult to identify what caused the reaction. Skin tests with standard
Allergic conjunctivitis Horner-Trantas dots are specific features of vernal type. Giant papillary conjunctivitis is not a true ocular allergic reaction and is caused by repeated mechanical irritation of the conjunctiva. Repeated contact with the conjunctival surface caused by the use of contact lenses is associated with GPC. PKC results from a delayed hypersensitivity/inflammatory reaction to antigens expressed by various pathogens. Common agents include Staph. aureus, Mycobacterium tuberculosis, Chlamydia and Candida. A detailed history allows physicians to determine whether the presenting symptoms are due to an allergen or another source. Diagnostic tests such as conjunctival scrapings to look for eosinophils are helpful in