context: If you have sensitive skin, you know that a new soap or cosmetic can trigger an outbreak of redness, itching, or stinging. But are you aware that your home also might harbor other common skin irritants, including triple-antibiotic ointments, bandage adhesives, and jewelry that contains metals such as nickel? When your skin becomes inflamed after coming in contact with one of these substances -- or many more -- the condition is called contact dermatitis. People with sensitive skin can get two types: This form is more common, accounting for 80% of contact dermatitis cases. When an irritating substance touches your skin, you'll often get a reaction that resembles a burn with red, chapped, and dry skin. This skin reaction tends to be more painful than itchy. Irritant contact dermatitis is typically triggered by common substances that we are repeatedly exposed to, including: Strong soaps Detergents Drain cleaners Acids Acetone in nail polish removers Plants People vary widely in their sensitivity to irritants. Some with sensitive skin can develop irritation from even mild soaps and detergents that they use frequently. Also, if you do a lot of housework that exposes your skin to cleaning products, ranging from detergents to waxes, you can wear down your skin's protective barrier enough to develop irritant dermatitis. Typical irritant contact dermatitis symptoms include: Dry, cracked skin Mild skin swelling Blisters or painful ulcers on the skin Stiff, tight-feeling skin This less common form is a true allergic reaction. In allergic contact dermatitis, the immune system responds to a substance that touches the skin. You can become allergic to the substance after one exposure or many. In fact, people can be exposed to a substance for long periods, even years, before developing an allergy. Common sources of allergic contact dermatitis include: Fragrances Preservatives Cosmetics Poison ivy Topical antibiotics Rubber or latex Metals in jewelry, such as nickel Some people are also allergic to over-the-counter topical triple-antibiotic ointments. All told, thousands of substances can cause allergic dermatitis. When a person who has become sensitized to an allergen becomes exposed by touching the substance, symptoms, such as itching and skin inflammation, are often delayed. They can show up anywhere from a few hours to as many as four days after contact. Symptoms of allergic contact dermatitis include: Reddened skin Darkened, leathery, cracked skin Dry, scaly patches of skin Burning or intense itching Blisters that ooze Hives Sun sensitivity Swelling in the eyes, face or genital area In addition, some people get a form called photoallergic contact dermatitis. This type happens only after the skin touches certain substances and then comes in contact with sunlight. These substances may include: Lime juice Sunscreens Aftershave lotions Antibiotics and some perfumes If you suspect that a certain product or substance is causing your dermatitis, avoid it and watch whether your rash improves. But it's not always easy to pinpoint a specific cause. For example, your eyelids may be chronically dry, red and flaky, but what's to blame: your eyeshadow, eyeliner, makeup remover, or overnight eye cream? Sometimes, people have no clue at all -- they get a rash, but they can't recall the substances that have touched their skin. Or their facial skin becomes inflamed, leading them to suspect a face product. In fact, they might have unwittingly transferred a substance from their hands to their face. The substance doesn't affect the hands, but the more sensitive facial skin will react. If you can't figure out the source of irritation, see a dermatologist. He or she will quiz you about your job, household chores, hobbies, drug and cosmetics use, and other factors in order to gain clues about the root of the problem. Your doctor may also do testing. No test can be performed for irritant contact dermatitis. But your doctor may do patch testing to see if you're sensitive to various types of allergens that are known to cause dermatitis. Small patches of these substances are placed on your skin for one to two days so that your doctor can check if a rash develops. To relieve itching, contact dermatitis is commonly treated with: Oral or topical steroids Oral antihistamines Skin emollients Oatmeal baths Once you're no longer exposed to the irritant or allergen, redness usually vanishes after a week. But itching, scaling, and temporary skin thickening may go on for days or weeks. You can also take steps to protect your sensitive skin from developing contact dermatitis. For example: Once you've identified an offending substance, avoid it. Wear gloves or protective clothing to prevent exposing your skin to cleansers, weeds, and other substances during housework or yard work. If your skin makes contact, wash the substance off right away with soap and water. Learn to recognize poison ivy and poison oak. Use mild, unscented laundry detergent. If you have sensitive facial skin, consider using gentle, soap-free, liquid cleansers. Or use a moisturizing soap that's free of fragrance and dyes. Don't scrub your face vigorously with a rough washcloth or buff puff. Instead, cleanse gently and pat dry. Avoid deodorant or antibacterial soaps. Choose moisturizers, sunscreens, and cosmetics that are fragrance-free and don't contain acids or botanical ingredients. Physical sunblocks that contain zinc oxide or titanium oxide are less likely to cause skin problems than chemical sunscreens. Test cosmetics and personal care products before using. Apply a small amount of the new product twice a day to a small patch of skin near the inside of your elbow. If no irritation occurs in that spot after a week, you can try using the product. Protect your skin by applying petroleum jelly or a thick, moisturizing cream two or three times a day.