We react more sensitively, so that your skin doesn’t.
Allergies are reactions by the body caused by hypersensitivity in the immune defence system to otherwise harmless environmental substances. Allergies begin with sensitisation at the first contact with the allergen. Allergies are divided into four types.
The most common type of allergy, type I, is an immediate reaction in which histamine and other inflammatory messengers are released through the binding of allergens to antibodies. Type I allergies include hay fever, allergic asthma and hives. Contact allergies are delayed type IV allergies. Inflammatory reactions occur 12 to 72 hours after contact with the allergen.
Type II and type III allergies are less common. Type II allergies includes transfusion reactions where antibodies bind with cellular antigens. In type III allergies, immune complexes are formed from antigen-antibody complexes which clog fine vessels and can have a tissue-damaging effect.