Allergic Contact Dermatitis (ACD) is a type of skin inflammation caused by allergens that come into contact with the skin. There are various synonyms for ACD including allergic eczema, allergic dermatitis, contact allergy, contact eczema, and allergic skin reaction. These terms all refer to the same condition, where the immune system reacts to a foreign substance by triggering an inflammatory response in the skin. The most common allergens causing ACD are metals (such as nickel), fragrances, preservatives, and rubber compounds. Symptoms of ACD can include redness, swelling, and itching, and it can occur anywhere on the body where the allergen touches the skin. Treatment for ACD involves avoiding the allergen and using topical steroids to reduce inflammation.