health

The causes of eczema are a matter of debate among doctors. For many
years it was thought that eczema is primarily an allergic disease that
leads to skin dryness and rashes. Doctors maintained that eczema from
an immune overreaction inside the body that leads to inflammation and cracked,
itchy skin. The breaks in the skin then let in more allergens, irritants, and
microbes that made the skin itch and burn even more. The theory was
supported by the observation that patients with eczema often develop
other atopic ailments such as asthma, food allergies, and hay fever.
In 2006, however, a researcher in Scotland found that children with
chronic eczema have a defective gene for filaggrin, a protein in the skin
that normally holds in moisture. The researcher discovered that between
a third and a half of his patients had a defective filaggrin gene on chromosome
1. A genetic factor may help to explain why eczema has increased in
developed countries since the 1980s; air pollution and the widespread
use of air conditioning and central heating could further dry out skin that
is already dry and fragile, allowing irritants to enter and trigger the inflammation
that characterizes eczema. On the other hand, many patients with
eczema do not have the defective filaggrin gene, while others with the gene
do not develop eczema.
At one time it was thought that emotional stress caused eczema. It is
now known that while stress can make a flare-up of eczema worse, it does
not cause the disorder.

The symptoms of eczema may include:

• Areas of dry, leathery, or discolored skin.
  
• Intense itching in the affected areas.
  
• Blisters that ooze tissue fluid and then crust over.
  
• Rash. In children, the rash is most often found on the face, elbows,
  and knees; in adults, it is more common on the skin inside the
  knees and elbows.
  
• Raw areas of skin from scratching.
  
• Reddened or inflamed skin around the blisters.
  
• Bacterial infections that develop in the broken skin.