Allergic eczema, also known as contact dermatitis, is a skin condition that occurs when a person's skin comes into contact with an allergen.
Allergic eczema causes a red and itchy rash, which can become painful and infected without treatment.
In this article, learn about the causes and symptoms of allergic eczema, as well as the treatment options.
Allergic eczema is a form of eczema that occurs in response to contact with an allergen. An allergen is any substance to which a person may be allergic. It is commonly called contact dermatitis.
The primary symptom of allergic eczema and other eczema types is a dry, itchy rash. Some types of eczema may be painful or cause blisters to form.
Researchers do not fully understand why eczema occurs in some people and not others. However, there are specific environmental triggers, and it is likely that genetics also play a role.
A person can experience allergic eczema after touching an allergen, consuming something they are allergic to, or coming into contact with an airborne allergen, such as pollen.
Some of the most common causes of contact dermatitis include:
- cocamidopropyl betaine, a detergent that manufacturers use to thicken shampoos, lotions, and soaps
- metals, such as chromium, cobalt, and nickel
- paraphenylenediamine (PPD), a chemical that commonly occurs in hair dye
- preservatives, such as formaldehyde
- antibacterial ointments, including neomycin and bacitracin
- antifungal or antibacterial products, such as methylisothiazolinone
Exposure to these allergens will not cause eczema in most people but may trigger a reaction in people with the condition.
Symptoms of allergic eczema usually only occur in the area of the skin that comes into contact with the allergen. However, people who have severe reactions may notice the symptoms elsewhere.
The most common symptoms of allergic eczema include:
The hands are often the most vulnerable to allergic eczema symptoms because they are more likely to touch items that cause an allergic reaction.
According to the National Eczema Association, three types of contact dermatitis occur most frequently:
- Allergic contact dermatitis: This condition occurs when a person's skin comes into contact with an allergen, such as nickel, paint, hair dye, or flowers. The reaction may not occur until 48–96 hours after exposure.
- Contact urticaria: This condition causes significant swelling and redness almost immediately after contact with an allergen. A person with contact urticaria can even experience an anaphylactic reaction, which is a severe reaction that causes breathing difficulties.
- Irritant contact dermatitis: This condition causes skin inflammation when the skin comes into contact with an irritant, such as soap, friction, or heat. A person with a wound or atopic dermatitis is more likely to experience irritant contact dermatitis.
The best treatment for allergic eczema is prevention, which means avoiding any irritants known to cause the reaction.
Avoiding allergens can be difficult though, especially if a person comes into contact with them as a result of their occupation.
Other treatments for allergic eczema include:
- applying an over-the-counter (OTC) hydrocortisone cream to reduce itching
- moisturizing the skin at least twice daily with a fragrance-free moisturizer
- taking antihistamines
- taking oatmeal baths
- wearing protective clothing and gloves when in contact with a known allergen
If a person has a severe allergic eczema reaction, which may involve extreme swelling with oozing and crusting, they should see their doctor. A doctor may prescribe an oral or topical antibiotic to prevent infection.
Another common treatment for allergic eczema is light therapy or phototherapy. Research has shown that exposure to special types of light can reduce eczema symptoms in some people. However, a person should only use phototherapy with a doctor's prescription.
There are several different types of eczema. In addition to allergic or contact dermatitis, other eczema varieties include:
- Atopic dermatitis: Atopic dermatitis is a chronic skin condition that often begins in childhood. The condition causes dry skin, redness, itching, and cracking. People with a family history of asthma or hay fever (allergic rhinitis) are more likely to develop atopic dermatitis.
- Dyshidrotic eczema: This eczema type causes small blisters, typically on the fingers, toes, and palms, and on the soles of the feet. Women are more likely to experience this condition than men. Dyshidrotic eczema is sometimes due to stress, moisture, or prolonged exposure to certain metals or chromium salts.
- Nummular eczema: Nummular eczema causes coin-shaped, itchy, scaly spots to develop on the skin. Sometimes the affected areas can turn into open sores. The condition most often occurs after an insect bite.
- Stasis dermatitis: Also called venous eczema, stasis dermatitis occurs when a person has poor circulation to their lower legs. This causes excess fluid to leak from the veins, resulting in swelling, itching, scaling, and pain.
Allergic eczema or contact dermatitis is an itchy, irritating skin condition that occurs after exposure to certain allergenic substances. These reactions may occur immediately, or there may be a delay.
In addition to avoiding the allergen, a person can usually treat eczema with OTC creams, including topical hydrocortisone.
If a person has a severe reaction with open sores, they should see a doctor for antibiotics or prescription treatments.