Contact and Allergic Dermatitis

Contact dermatitis or contact eczema is a cutaneous inflammatory reaction caused by an external agent coming into contact with the skin. In Allergology, we understand four types of dermatitis: allergic, irritant, phototoxic and photoallergic.

Allergic contact dermatitis occurs as a result of a specific response of the skin to a substance (allergen) to which it has been previously sensitized by a mechanism of delayed type IV hypersensitivity. It occurs in predisposed individuals, is not predictable, never occurs on first contact and may affect the entire skin.

Symptoms and treatment of contact dermatitis

Symptoms vary according to the stage of the contact dermatitis, ranging from redness, edema and small vesicles to chronic stages, with dry, thickened, lichenified skin, etc. Frequently, they are usually pruritic lesions.

The ideal treatment of contact dermatitis is to avoid friction with the causative agent. This requires a correct diagnosis by means of a detailed clinical history and epicutaneous or patch tests.

Patients with a greater predisposition to suffer from contact dermatitis are those with other skin diseases that alter the cutaneous barrier, such as atopic dermatitis, psoriasis, etc. Depending on the allergen, some professions or hobbies are more exposed to suffer it as it is the case of the paraphenylenediamine element in hairdressing, potassium dichromate in construction workers, rubbers in health workers, nickel sulfate by the use of costume jewelry, etcetera.

The basis of symptomatic treatment is antihistamines to reduce itching, topical and sometimes systemic corticosteroids and antibiotics in case of superinfection.