- Eczema is not a single disease but a reaction pattern of the skin produced by a number conditions.
- Atopic dermatitis, a common causes of eczema, is more prevalent in those with asthma and hay fever.
- Eczema appears as small blisters that can weep and ooze, or as crusted, thickened plaques of skin. It is almost always quite itchy.
- It is important to distinguish the different kinds of eczema because effective treatments often differ.
- If eczema is produced by skin exposure to a specific substance, it can be helpful to avoid it.
- Keeping the skin healthy and moisturized can prevent many kinds of eczema.
What is eczema?
Rather than a specific condition, eczema is a group of unrelated diseases that have a similar appearance. When it is new eczema, the affected skin appears red and elevated with small blisters (vesicles) containing a clear fluid. When the blisters break, the affected skin will weep and ooze. In older eczema, chronic eczema, the blisters are less prominent and the skin is thickened, elevated, and scaling. Eczema almost always is very itchy.
Are there different types of eczema?
There are at least 11 different types of skin conditions that produce eczema. In order to develop a rational treatment plan, it is important to distinguish them. This is often not easy.
- Atopic dermatitis: This condition has a genetic basis and is probably most commonly called eczema. Atopic dermatitis tends to begin early in life in those with a predisposition to inhalant allergies, but it probably does not have an allergic basis. Characteristically, rashes occur on the cheeks, neck, elbow and knee creases, and ankles. Rarely, a few those with atopic dermatitis can get an extensive herpes simplex infection called "eczema herpeticum."
- Irritant dermatitis: This occurs when the skin is repeatedly exposed to toxic substances.
- Allergic contact dermatitis: After repeated exposures to the same substance, the body's immune recognition system becomes activated at the site of the next exposure and produces eczema.
- Stasis dermatitis: It commonly occurs on the swollen lower legs of people who have poor circulation in the veins of the legs.
- Fungal infections: This can produce a pattern identical to many other types of eczema, but the fungus can be visualized with a scraping under the microscope or grown in culture.
- Scabies: It's caused by an infestation by the human itch mite and may produce a rash very similar to other forms of eczema.
- Pompholyx (dyshidrotic eczema): This is a common but poorly understood condition which classically affects the hands and occasionally the feet by producing an itchy rash composed of tiny blisters (vesicles) on the sides of the fingers or toes and palms or soles.
- Lichen simplex chronicus: It produces thickened plaques of skin commonly found on the shins and neck.
- Nummular eczema: This is a nonspecific term for coin-shaped plaques of scaling skin most often on the lower legs of older individuals.
- Xerotic (dry skin) eczema: When the skin becomes pathologically dry, it will crack and ooze.
- Seborrheic eczema: It produces a rash on the scalp, face, ears, and occasionally the mid-chest in adults. In infants, in can produce a weepy, oozy rash behind the ears and can be quite extensive, involving the entire body.