Basic information: allergic eczema


What Is Allergic Eczema?

When your body comes in contact with something that could make you ill, your immune system promotes chemical changes to help your body ward off disease. You are exposed to thousands of substances each day, and most will not cause your immune system to react. However, you may come into contact with substances that are not typically harmful to the body but cause your immune system to overreact nonetheless. These substances are known as allergens, and this overreaction is known as an allergy.

An allergic reaction can take a number of forms. For some people, breathing becomes difficult, they cough, and they experience burning eyes and a runny nose. Other allergic reactions cause changes in the skin. Allergic eczema is an itchy skin rash that develops when you come into contact with an allergen. The condition often occurs hours after you have been exposed to the substance that causes the allergic reaction.

Allergic eczema is also known as:

  • Allergic dermatitis;
  • Contact dermatitis;
  • Allergic contact dermatitis;
  • Contact eczema.

What Causes Allergic Eczema?

Allergic eczema occurs when you come into direct contact with an allergen. This type of allergic reaction is known as delayed allergy because it can take several exposures to the allergen to cause a reaction. Also, the symptoms of allergic eczema may not develop for 24 to 48 hours after you have come in contact with the allergen.

Although allergic eczema can develop because of an immune response to any substance, some common triggers include:

  • Nickel, which can be found in earrings, jewelry, belt buckles, and metal buttons on jeans;
  • Perfumes found in cosmetics;
  • Certain clothing dyes;
  • Hairdressing chemicals and hair dye;
  • Latex;
  • Adhesives;
  • Antibiotic creams or ointments used on the skin such as neomycin.

Allergic eczema may also result when the skin is exposed to chemicals in the presence of sunlight. One example is an allergic reaction that occurs after using sunscreen and spending time in the sun.

Recognizing the Signs of Allergic Eczema

The symptoms of allergic eczema will be different for each person. They may also change over time. Symptoms typically develop on the skin where contact with the allergen has occurred. In rare cases, symptoms may spread to other areas of the skin.

Common symptoms include:

  • Itching of the skin;
  • A burning sensation or pain on the skin;
  • Red bumps on the skin that may ooze (weep), drain, or crust;
  • Warm, tender skin;
  • Skin that becomes scaly, raw, or thickened;
  • Skin that becomes dry, red, or rough;
  • Inflammation of the skin;
  • Cuts (fissures) in the skin;
  • Skin rash.

How Is Allergic Eczema Diagnosed?

If you have symptoms of this disorder, your doctor will examine your skin. Although your doctor may be able to diagnose an allergic reaction, he or she may need to do further testing to determine exactly what you are allergic to. Typically an epicutaneous (on the surface of the skin) or patch test will be required.

Patch Test

During this test, patches that contain common allergens are placed on your back. These patches remain in place for 48 hours. When your doctor removes the patches, he or she will check for signs of an allergic reaction. Your doctor will check your skin again in two more days to see if there is a delayed allergic reaction.


If your doctor is not able to make a diagnosis based on the patch test, other tests may be needed. Your doctor may perform a skin lesion biopsy (taking a sample of your skin for laboratory testing) to make sure that your skin condition is not due to another health problem.

How Is Allergic Eczema Treated?

Treatment for allergic eczema depends on the severity of your symptoms. In all cases, it is important to wash the affected skin with plenty of water to remove traces of the allergen.

If your symptoms are mild and do not bother you, no further treatment may be needed. You may wish to use a moisturizing cream to keep the skin hydrated and to repair damages. Over-the-counter corticosteroid creams can help with itching and inflammation.

If your symptoms are severe, your doctor may recommend prescription-strength ointments or creams. Corticosteroid pills or a shot can also be prescribed if needed.

With treatment, you can expect allergic eczema to clear up within two to three weeks. However, the condition may return if you are exposed to the allergen again. Identifying the allergen that caused your eczema and taking steps to avoid it are critical to preventing future reactions.

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