Final answer:
The diagnosis of occupational contact dermatitis includes taking a detailed patient history, identifying levels of exposure through job functions, and conducting skin tests like the PPST or intradermal tests to observe for type I and IV hypersensitivity reactions.
Step-by-step explanation:
Diagnosis of Occupational Contact Dermatitis
Establishing the diagnosis of occupational contact dermatitis requires a multi-faceted approach. Due to the variety of potential irritants and allergens in different work environments, diagnosis often starts with a detailed patient history, with an emphasis on understanding the specific job functions and corresponding levels of exposure. Most occupational exposures are through skin absorption, and occasionally enhanced by inhalation, especially in enclosed settings with spraying operations.
To determine the specific causes of contact dermatitis for an individual, skin testing for common allergens can be one of the methods used. One such technique is the puncture skin test, which introduces potential allergens via superficial skin. This test is observed for signs of a wheal-flare reaction, indicating type I hypersensitivity. Another method is the intradermal test, involving the injection of a small amount of allergen directly into the dermis to observe for similar reactions.
Contact dermatitis is a type IV hypersensitivity reaction. For certain allergens, such as poison ivy, the first exposure may not provoke a reaction, but it sensitizes the immune system. Subsequent exposures can activate memory helper T cells, resulting in the production of inflammatory cytokines and an inflammatory response in the skin. This response continues until the allergen is removed and can cause significant tissue damage if prolonged.