The real cause of eczema remains unknown. It is thought that eczema is a result of several factors that include genetic susceptibility, abnormal immune system responses and lowered skin barrier function.
Eczema starts early and an estimated 65% of sufferers first developed symptoms before they completed one year of age. Fully 90% of patients showed symptoms before they turned five years old. In fact, six to twelve weeks is the most common age range during which eczema symptoms develop. It is very rare for people over age 30 to show eczema symptoms for the first time. The early onset of the disease probably has to do with the fact that genetics is a key cause of eczema.
Racial and Ethnic Groups
While digging into the cause of eczema researchers evaluated the incidence of the disease among various racial and ethnic groups. The evidence they found is conflicting. There are studies that indicate no differences in the incidence of eczema among various races. However, other studies appear to show that native Americans and Africans Americans have lower risks of developing eczema when compared to Caucasians or Asians. Others counter this pointing out that the skin lesions characteristic of eczema are more difficult to detect among African Americans due to their skin pigmentation.
Both males and females seem to have an approximately equal chance of developing eczema. Therefore sex does not appear to be a cause of eczema.
Eczema is generally characterized by skin inflammation, mild to severe itchiness, redness and ooziness. Among children, age has a bearing on how the skin lesions are distributed. In infants, the lesions occurred mostly on the hands, feet, diaper area, face, scalp etc. Fluid usually oozes from these lesions. In older children, the insides of the elbows, the back of the neck, backs of the knees, ankles and wrists tend to be affected.
In older children, skin lesions do not usually exude fluid and are often lichenified. The term lichenification refers to a thickening of the skin cells of the epidermis, which is the outermost layer of the skin, into a leather-like or bark-like formation. This is the result of scratching the itchy lesions over an extended period of time. Lichenified skin makes normal skin markings more prominent.
Since genetic factors are a cause of eczema, researchers have tried to identify the specific gene that predisposes a person to developing the disease. It is theorized that loci on chromosomes 11 and 13 are connected to this skin disorder. If one parent has eczema, a child has a 60% chance of developing the disease. If both parents have it, the odds increase to 80%. Approximately 40% of children diagnosed with the disease have at least one close relative who has the disease.
Fatty Acids and Eczema
Another cause of eczema is a little-understood, complex process involving inflammation, skin abnormalities and the immune system. Researchers have discovered that levels of fatty acids in the skin are lower in eczema patients. This could be a factor that leads to the high rates of moisture loss from the skin. It may also be a reason why eczema patients are unusually sensitive to environmental irritants and chemicals.
In addition, it appears that eczema patients produce lower levels of a hormone called interferon-gamma. This hormone plays a role in the body’s response to allergic substances. Low levels of this compound may be a cause of eczema and the reason behind the hypersensitivity shown by eczema patients.
While the ultimate cause of eczema is still elusive, researchers are finding new clues that may eventually lead to a more comprehensive understanding of the disease and perhaps a cure as well.