Contact Allergies

Contact dermatitis accounts for 20% of all contact allergies. It is a condition which is essentially a delayed hypersensitivity syndrome that is a phased interaction of antibodies and allergens.

Phases of contact allergy

Contact Dermatitis Sensitization Phase: In this stage the skin comes into contact with the antigens. The antigens that cause this reaction have low molecular weight and penetrate the exterior layer of the epidermis. White blood cells called T lymphocytes receive the antigen which is processed by cells in the base layer of the epidermis. The T lymphocytes interpret the antigen as a foreign and unwelcome particle and reach the epidermis after circulating through the bloodstream.

Contact Dermatitis Elicitation Phase: The elicitation phase occurs in sensitized people who are re-exposed to the antigen. The T lymphocytes in the epidermis produce inflammatory chemicals which are meant to eradicate the antibody. This leads to skin rashes and develops within 2 to four days of re-exposure to the antigen and may last up to 4 weeks.

Contact Dermatitis Appearance: The breakout of rashes has a pattern it may be the same size and shape as the contact item such as buckle, waistband or watch. In most cases, the rash does not have the same size or shape. The contact and infected area is red and itchy and has characteristics such as fissuring, lichenification, vesicles and scaling.