Skin Allergy

What is skin allergy?

The two most common types of skin allergy are called contact dermatitis and urticaria. Contact dermatitis takes the form of red, itchy patches which may blister and crust over. The patches appear on the part of the skin that was in contact with a particular substance, like a piece of jewelry or certain cosmetics. Urticaria, or hives, causes red, itchy, raised areas on the skin. Hives can be very large and cover a large area of the skin. Acute hives arise quickly and can last up to 6 weeks. One cluster may disappear as another cluster develops. They can be alarming, but usually go away within 24 hours. Foods, medicines, heat, cold, exercise, or virus infections may cause hives, but often the cause is unknown. Chronic hives can last 6 months or more. To make a diagnosis, a healthcare provider will see what the rash looks like, where it started, and ask about recent contacts.

Eczema is also an allergic skin reaction, although it is more common in babies and young children than in older adults.

How does it occur?

Before you can have a reaction to a particular substance, your immune system (your body's natural defense against infection and other foreign material) must first be sensitized to it. This happens in an earlier contact with the substance. Once sensitized, your body will react every time you have contact with that substance. Most of the reactions caused by skin care products are on the face, hands, and body, where these products are used.

Other causes include hair care products (such as chemicals in hair dyes or permanents) and metals (such as jewelry containing nickel). The worst offenders are:

• after shave products and bath powders
• fragrance in perfumes and skin products
• household products
• poisonous plants, such as poison ivy
• preservatives.

In recent years a reaction to latex (rubber) has become more common. Latex can be found in balloons, rubber bands, condoms, elastic bands, clothes (stretch latex bathing suits, underwear, waist bands), and rubber toys. Exposure can begin at an early age. Reactions to latex can come in the form of contact dermatitis, asthma, and in very severe cases anaphylactic shock. If you have an allergy to latex or tape, be sure to tell your doctor, dentist, and other healthcare workers, so they do not use these products when caring for you.

What are the symptoms?

Symptoms may include:

• red, itchy patches on the skin in areas of contact with particular substances
• blisters and crusts
• raised, red, itchy areas on the skin after certain medicines or foods
• a red, raised area around a recent insect bite.

How is it diagnosed?

You may recognize the symptoms yourself, based on previous experience. If you seek medical treatment, your healthcare provider will examine the rash and ask you about contact with substances to which you may be allergic. Your healthcare provider will want to know if you have taken any medicine (including nonprescription medicines) and what you have eaten recently.

How is it treated?

No permanent cure exists for skin reactions. The best strategy is to avoid the causes. The best prevention for dermatitis and eczema is a good moisturizing lotion. You should also change to non-allergenic and fragrance-free products. If contact dermatitis, eczema, or hives do occur, they can often be treated with over-the-counter antihistamines such as Benadryl or cortisone preparations. Scratching, rubbing, or exposing a rash to extremes of hot or cold can irritate or make the rash worse.

Any time home care does not help or the skin reaction gets worse or comes back, see a healthcare provider. The best way to prevent skin allergies is to stay away from the cause.

How can I take care of myself?

• Follow your healthcare provider's advice for treating your skin allergy.
• Contact your provider right away if you have trouble swallowing or breathing.
• See your healthcare provider if a reaction is severe or unusual.
• Tell your healthcare provider if you have ever had a reaction to any medicines.
• Avoid substances (certain jewelry or cosmetics, for example) that irritate your skin.
• Avoid foods you know are likely to cause a skin reaction. If you eat with friends, tell them in advance if you should avoid certain foods. If you're not sure about the ingredients in food in a restaurant, don't eat it.