Atopic dermatitis is the most common of the many types of eczema, and sometimes people use the two terms interchangeably. But there are many terms used to describe specific forms of eczema that may have very similar symptoms to atopic dermatitis.

Atopic dermatitis

Atopic dermatitis is a chronic skin disease characterized by itchy, inflamed skin. Atopic dermatitis is believed to be caused by an abnormal function of the body's immune system. The condition tends to come and go, depending upon exposures to triggers or causative factors. The most common form of eczema, atopic dermatitis, affects about 10% of infants and 3% of adults in the U.S. Around two-thirds of those who develop the condition do so prior to age 1. When the disease starts in infancy, it is sometimes termed infantile eczema. Atopic dermatitis tends to run in families, and people who develop the condition often have a family history of allergic conditions such as asthma or hay fever.

Contact eczema

Contact eczema (contact dermatitis) is a localized reaction that includes redness, itching, and burning where the skin has come into contact with an allergen (an allergy-causing substance to which an individual is sensitized) or with a general irritant such as an acid, a cleaning agent, or other chemical. Other examples of contact eczema include reactions to laundry detergents, nickel (present in jewelry), cosmetics, fabrics, clothing, and perfume. Due to the vast number of substances with which individuals have contact, it can be difficult to determine the trigger for contact dermatitis. The condition is sometimes referred to as allergic contact eczema (allergic contact dermatitis) if the trigger is an allergen and irritant contact eczema (irritant contact dermatitis) if the trigger is an irritant. Skin reactions to poison ivy and poison sumac are examples of allergic contact eczema. People who have a history of allergies have an increased risk for developing contact eczema.

Seborrheic eczema

Seborrheic eczema (seborrheic dermatitis) is a form of skin inflammation of unknown cause. The signs and symptoms of seborrheic eczema include yellowish, oily, scaly patches of skin on the scalp, face, and occasionally other parts of the body. Dandruff and "cradle cap" in infants are examples of seborrheic eczema. It is commonplace for seborrheic dermatitis to inflame the face at the creases of the cheeks and/or the nasal folds. Seborrheic dermatitis is not necessarily associated with itching. This condition tends to run in families. Emotional stress, oily skin, infrequent shampooing, and weather conditions may all increase a person's risk of developing seborrheic eczema. One type of seborrheic eczema is also common in people with AIDS.