Eczema
print Print
 
 
 
 
 
 
 
 
 
 
Text Label
Text minus
Text plus
What is eczema?

Eczema is a condition that causes areas of your skin to become itchy, red, painful and swollen. Scratching can make the skin bleed. It can also make the eczema worse. Sometimes the skin becomes thick and scaly.

If you're a child and have eczema, there's a good chance you'll grow out of it. But some people have eczema all their life. There's no cure for eczema, but there are many treatments that can help reduce the itchiness and
 
 
 
 
 
inflammation
If your skin or some other part of your body becomes red, swollen, hot or sore, we say it is inflamed. It means that your body is trying to protect you from germs, from something in your body tissues that can hurt you (like a thorn or sliver), or from things that cause allergies (allergens). Inflammation is part of the way the body heals an infection or injury.
 
 
 
 
 
inflammation. There are also things you can do at home to keep eczema under control.

There are several types of eczema. The most common type is atopic eczema.
 
 
 
 
 
Source:
National Institute of Arthritis and Musculoskeletal and Skin Diseases.
Atopic dermatitis: diagnosing atopic dermatitis.
August 2005. Available at http://www.niams.nih.gov/Health_Info/Atopic_Dermatitis/atopic_dermatitis_ff.asp (accessed on 22 April 2009).
 
 
 
 
 
1 If a condition is described as atopic, it means that it's caused by an allergy. The information here is about atopic eczema, but we call it just plain "eczema."

Key points about eczema
  • About 1 in 10 children in the United States have eczema.
  • About 4 in 10 children who have eczema grow out of it.
  • Some people have mild symptoms that last a few days at a time, while other people may have more severe symptoms that last longer or never go away completely.
  • Eczema can be irritating and painful, but it shouldn't keep you or your child from taking part in activities.
  • There are good treatments that can help keep symptoms under control.
  • You may be able to prevent eczema in your baby by breastfeeding and avoiding certain foods.
Your skin
To understand what happens in eczema and how to treat it, it helps to know something about your skin.

If you have eczema, it makes your skin itchy. But there are treatments that can help.

  • Skin protects your body from infection and injury. The surface of your skin is made up of a thick layer of dead skin cells. These form a tough barrier that keeps poisons and bacteria from getting into the body. That barrier also helps to hold the body's moisture. The dead cells eventually flake off or are washed away. They are always being replaced by new cells that grow from underneath.
     
     
     
     
     
    Source:
    Martini FH, Ober WC, Garrison CW, et al.
    Fundamentals of anatomy and physiology.
    5th edition. Prentice Hall, New Jersey, U.S.A.; 2001.
     
     
     
     
     
    2
  • Skin keeps itself moist and soft so that it can bend and stretch without breaking. The thick layer of dead cells in the skin holds water. This makes the skin feel soft. The skin also makes a kind of thick, oily liquid called sebum that helps the skin stay moist. Without sebum, the layer of dead cells would dry out and get brittle. When you wash with soap, you take sebum off your skin. This is why your skin and scalp will feel dry if you wash often.
     
     
     
     
     
    Source:
    Martini FH, Ober WC, Garrison CW, et al.
    Fundamentals of anatomy and physiology.
    5th edition. Prentice Hall, New Jersey, U.S.A.; 2001.
     
     
     
     
     
    2
Your skin does many other jobs, too. For example, it helps keep your body temperature normal by letting extra blood flow to the surface and by making sweat when it's hot. Skin also contains a lot of nerves that give you your sense of touch. When you're in the sun, your skin makes vitamin D.

Eczema can make your skin red and itchy. Scratching can make the skin bleed.

What goes wrong in eczema
In eczema, the skin becomes inflamed. It gets red, itchy, thick and sore. When you scratch the skin, it starts a vicious cycle. Here's what happens.
 
 
 
 
 
Source:
National Institute of Arthritis and Musculoskeletal and Skin Diseases.
Atopic dermatitis: diagnosing atopic dermatitis.
August 2005. Available at http://www.niams.nih.gov/Health_Info/Atopic_Dermatitis/atopic_dermatitis_ff.asp (accessed on 22 April 2009).
 
 
 
 
 
1
 
 
 
 
 
Source:
Peters J.
Eczema.
Nursing Standard. 2000; 14: 49-56.
 
 
 
 
 
3
 
 
 
 
 
Source:
Zug KA, McKay M.
Eczematous dermatitis: a practical review.
American Family Physician. 1996; 54: 1243-1250, 1253-1254.
 
 
 
 
 
4

  • The top layer of skin starts to get flaky and dry.
  • The broken, flaky skin can't hold water well and the skin becomes dry.
  • When skin is dry and flaky, bacteria and other irritants, such as dust or chemicals, can get into the skin. This can lead to an infection and make the itchiness worse. (See Infections and eczema to find out more.)
  • The skin can become thick and scaly, with small raised bumps or blisters.
  • If you scratch the blisters, they may ooze and even bleed.
  • Scratching makes the itch worse, and this leads to more scratching, and so on. Doctors call this the "itch-scratch" cycle.

What is an allergy?
The type of eczema we talk about here happens because of an allergy. If you have an allergy, your
 
 
 
 
 
immune system
The immune system is made up of the parts of the body that are devoted to fighting infection. The body is constantly being threatened by infections from things like bacteria, viruses and parasites. The immune system fights these infections in different ways. At the microscopic level, the immune system uses antibodies and white blood cells, which travel in the blood and target infectious agents, such as bacteria. These microscopic parts of the immune system either kill the infectious agent directly, or take it to other parts of the body, like the spleen, where it can be dealt with. The lymph nodes are another important part of the immune system. Within them, white blood cells filter through the foreign material that has entered the blood, to see if there are any infections. When you have a swollen gland during a cold, this is actually a lymph node that is reacting to the infection. Unfortunately, it is possible for the immune system to become confused and to use its destructive powers to target healthy parts of the body. Diseases that result from this type of situation are called autoimmune diseases.
 
 
 
 
 
immune system (your body's system for fighting infection) is supersensitive to certain things that are harmless to other people. Your body overreacts when you're around those things. It triggers changes called
 
 
 
 
 
allergic reaction
You have an allergic reaction when your immune system reacts to something outside your body that is normally harmless. You can be allergic to particles in the air, like pollen, which causes hay fever, or to chemicals, like detergents, which can cause a rash. People can also have an allergic reaction to drugs, like penicillin.
 
 
 
 
 
allergic reactions.

For example, in eczema your immune system's reaction makes your skin itchy. Other conditions that are linked to allergies include hay fever and asthma. In hay fever, an allergy to pollen makes people sneeze and makes their eyes runny. If you have asthma, something irritates your lungs, making you wheeze, cough and feel short of breath.

Allergies often run in families. But not everyone with eczema has it in their family.
 
 
 
 
 
Source:
Barnetson RS, Rogers M.
Childhood atopic eczema.
BMJ. 2002; 324: 1376-1379.
 
 
 
 
 
5

There are other types of eczema that aren't caused by an allergy. To read more, see Types of eczema.

Your immune system
Doctors think that people with atopic eczema might have overactive immune systems. If you have this, your immune system will cause an allergic reaction when you come into contact with certain things that don't bother most people. Things that set off an allergic reaction are called
 
 
 
 
 
allergen
If you have an allergy to something, your body overreacts when you're around it. The thing you are allergic to is called an allergen. Most allergens are harmless to most people. But if you're allergic to something, your body's system for fighting infection (your immune system) is too sensitive to that allergen. It triggers changes that we call allergic reactions. For example, pollen is an allergen for many people. If you're allergic to pollen, you'll sneeze and have runny eyes when pollen is in the air.
 
 
 
 
 
allergens. This is how the cycle of symptoms we find in eczema usually gets started.

Eczema happens differently in different people. Not everyone who has eczema reacts to the same things that trigger flare-ups in others. See Things that can trigger eczema for more information.

Some of the things that can trigger allergic reactions in people who have eczema are:

  • House dust mites
  • Animal dander
  • Stress
  • Some foods.
The role of food in eczema is not clear. It may be important for some people and not others. The same is true of stress. For some people, things like moving to a new house or starting a new job or school cause stress that's tied to eczema flare-ups.
 
 
 
 
 
Source:
Swerlick RA, Lawley TJ.
Eczema, psoriasis, cutaneous infections, acne, and other common skin disorders.
In: Braunwald E, Fauci AS, Kasper DL, et al (editors). Harrison's principles of internal medicine. 15th edition. McGraw-Hill, London, UK; 2001.
 
 
 
 
 
6

Why me?
Some people are more likely to get eczema than others. It's more common in families where a lot of people have allergies, like asthma and hay fever. Doctors think that eczema is inherited in the
 
 
 
 
 
genes
Your genes are the parts of your cells that contain instructions for how your body works. Genes are housed on chromosomes, structures that sit in the nucleus at the middle of each of your cells. You have 23 pairs of chromosomes in your normal cells, each of which has thousands of genes. You get one set of chromosomes, and all of the genes that are on them, from each of your parents.
 
 
 
 
 
genes we get from our parents.

If both parents have eczema, a child has an 80 percent chance of getting it, too. If just one parent has eczema, a child's chance of getting it is just over 50 percent.
 
 
 
 
 
Source:
Swerlick RA, Lawley TJ.
Eczema, psoriasis, cutaneous infections, acne, and other common skin disorders.
In: Braunwald E, Fauci AS, Kasper DL, et al (editors). Harrison's principles of internal medicine. 15th edition. McGraw-Hill, London, UK; 2001.
 
 
 
 
 
6

Eczema and the family
Children who have very bad eczema can get upset about their condition. And parents who are trying to help a child with eczema may find it stressful, too. See How eczema makes you feel for some ideas about why people get upset about eczema and what to do to make it easier.

Sources for the information on this page:
  1. National Institute of Arthritis and Musculoskeletal and Skin Diseases.Atopic dermatitis: diagnosing atopic dermatitis.August 2005. Available at http://www.niams.nih.gov/Health_Info/Atopic_Dermatitis/atopic_dermatitis_ff.asp (accessed on 22 April 2009).
  2. Martini FH, Ober WC, Garrison CW, et al.Fundamentals of anatomy and physiology.5th edition. Prentice Hall, New Jersey, U.S.A.; 2001.
  3. Peters J.Eczema.Nursing Standard. 2000; 14: 49-56.
  4. Zug KA, McKay M.Eczematous dermatitis: a practical review.American Family Physician. 1996; 54: 1243-1250, 1253-1254.
  5. Barnetson RS, Rogers M.Childhood atopic eczema.BMJ. 2002; 324: 1376-1379.
  6. Swerlick RA, Lawley TJ.Eczema, psoriasis, cutaneous infections, acne, and other common skin disorders.In: Braunwald E, Fauci AS, Kasper DL, et al (editors). Harrison's principles of internal medicine. 15th edition. McGraw-Hill, London, UK; 2001.
This information was last updated on May 01, 2009
BMJ Group
This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment.
© BMJ Publishing Group Limited 2010. All rights reserved.
Next in this section: What are the symptoms?