The child with poison ivy … the operating room nurse who develops scaly skin on her hands from frequent washing with potent antibacterial soaps … the elderly gentleman with crusty-looking, thickened skin on his arms and elbows … the young woman who seems to always get an angry neck rash neck after a cold … these people all have one thing in common: they are suffering from eczema. The term "eczema" encompasses a number of red, itchy skin conditions. Eczema may look like a dry, scaly rash or weepy, oozing blisters. People of any age can get it.

Eczema is a form of "dermatitis," which literally means, "inflamed skin." Chronic eczema causes dry, red flaky patches of skin, usually on the face, neck, scalp, the arms, elbows, wrists, hands, and knees. During acute flare-ups, the patches become itchy, oozing, and inflamed. The terms "dermatitis" and "eczema" are often used interchangeably.

Medical science classifies eczema and dermatitis into two main categories: contact dermatitis and atopic eczema. Contact dermatitis, also called contact eczema, occurs when an irritating substance comes in direct contact with the skin. The offending irritant may be a chemical, cosmetics, wool, lanolin, or rubber shoes. Nickel in jewelry is a common cause. Poison ivy is a form of contact eczema.

Atopic eczema is usually caused by inhaled or ingested allergens, such as foods, pollen, dust, or animal dander. Some medical literature discusses a third classification called "dysregulatory microbial eczema".(1) Bacteria that penetrate and inflame the outer skin layer trigger this type of eczema.

Atopic eczema is a hereditary condition that typically appears in early childhood. (The term "atopic" in general refers to inherited allergy-related conditions.) Children whose parents both have allergies are twice as likely to develop allergies themselves.(2) The prevalence of atopic allergies such as asthma and eczema has risen steadily since the 1960's, possibly, as some scientists believe, due to worsening environmental pollution.(2) Children with atopic eczema have a higher than normal risk of developing asthma and hay fever.(3)

Food allergies appear to play a significant role in atopic eczema. Infants and young children with severe eczema tend to produce antibodies against certain foods.(3) Some experts think infants whose mothers were exposed to allergy-causing substances during pregnancy have and increased chance of developing eczema, although not all agree. This point of view is strengthened by studies showing that breast-fed infants born to mothers who avoid allergic foods during pregnancy have a lower incidence of eczema.(4)

There appears to be a strong link between allergic sensitivity and the type of bacteria that predominate in the intestinal tract. In a healthy gut, the "friendly bacteria" such as acidophilus and bifidus have the upper hand. These good bacteria help prevent allergy-causing substances, known as "allergens," from inflaming the gut wall. If the friendly gut bacteria are absent, the immune system's response to allergens can set the stage for other allergic conditions. Colonization of the digestive system with the right bacteria needs to begin shortly after birth. If this is disrupted, the child may be prone to allergy-related conditions such as eczema.(5)