Contact allergy

Contact Allergy is a type of hypersensitivity reaction that occurs when the skin comes into direct contact with an allergen. This condition is also known as contact dermatitis or allergic contact dermatitis. It is a localized reaction that includes redness, itching, and burning where the skin has come into contact with an allergen. Unlike other allergic reactions that can affect the entire body, contact allergy is usually confined to the area of skin that was exposed to the allergen.

Causes

Contact allergy is caused by an immune system reaction to a substance (allergen) that the body identifies as foreign. This reaction occurs upon direct contact with the skin. Common allergens include nickel, latex, cosmetics, fragrances, poison ivy, and certain preservatives found in creams and lotions. The sensitivity to these allergens develops over time, with repeated exposure increasing the likelihood of an allergic reaction.

Symptoms

Symptoms of contact allergy can vary from mild to severe and include:

• Redness
• Itching
• Swelling
• Blisters
• Dry, cracked skin

In severe cases, the reaction can spread beyond the area of skin that was in direct contact with the allergen, although this is less common.

Diagnosis

Diagnosis of contact allergy is primarily based on the patient's history and a physical examination. Patch testing is the gold standard for identifying the specific allergens responsible for the reaction. During this test, small amounts of various allergens are applied to the skin, typically on the back, and covered with patches. The skin is then examined for reactions after 48 hours and again after 72 or 96 hours.

Treatment

The primary treatment for contact allergy is to identify and avoid exposure to the offending allergen. Topical corticosteroids may be prescribed to reduce inflammation and itching. In cases of severe reaction, systemic corticosteroids may be necessary. Emollients or moisturizers can help soothe and repair the skin. In some cases, phototherapy may be recommended.

Prevention

Prevention of contact allergy involves avoiding known allergens. This may require reading product labels carefully, wearing protective clothing, or using barrier creams. Individuals with known sensitivities should inform healthcare providers to avoid allergenic substances in medical products.

See Also

• Allergic reaction
• Dermatitis
• Immunology
• Patch testing