Contact dermatitis

Irritant contact dermatitis is caused by direct toxicity without prior sensitization, and allergic contact dermatitis is a delayed hypersensitivity reaction.

Results in localized burning, stinging, itching, blistering, redness, and swelling at the area of contact with the allergen or irritant.

Patch testing may aid identification of the causative agent. Skin biopsy may also be helpful, but may not be able to distinguish between other causes of dermatitis.

Treatment involves removal of the causative agent, future avoidance of the causative agent, topical corticosteroids, and/or a short course of oral corticosteroids.

Rarely, contact dermatitis can become generalized, leading to areas of dermatitis in locations distant from the site of contact with the causative agent.

Other allergic conditions may be triggered by exposure to an allergen, such as allergic rhinitis, asthma, and anaphylaxis.

Contact dermatitis is an allergic or irritant skin reaction caused by an external agent.