Type IV
Type of portland cement that is employed in the construction of massive concrete structures such a gravity dams
Type IV allergies, also known as delayed or cell-mediated hypersensitivity reactions, are immune responses that occur 48-72 hours after exposure to an allergen. These reactions involve T-cells and are not mediated by the antibody IgE. Common examples of Type IV allergies include contact dermatitis from exposure to poison ivy, nickel, or latex.
In order to diagnose a Type IV allergy, a medical professional will conduct a patch test. This involves applying a small amount of the suspected allergen to the skin and observing the area for any reaction over a period of 48-72 hours. If the area becomes inflamed, it is likely a Type IV allergy.
Treatment for Type IV allergies typically involves avoidance of the allergen and application of topical corticosteroids to alleviate symptoms. In severe cases, oral corticosteroids may also be prescribed.
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