Overview of Eczema (Dermatitis)

The terms eczema and dermatitis describe a reaction pattern of skin disorders with a variety of common characteristics. The acute disease typically is characterized by inflammation, redness, swelling, and itching, as well as some blistering and oozing. Skin biopsies show inflammatory cells and swelling.

When dermatitis becomes subacute, the intense reaction becomes milder, and the blisters begin to heal. Crusts and scale are common at this time.

Chronic dermatitis is identified by thickened, leathery skin with excess ridges, as well as dark and dull skin. Under the microscope, the outermost (epidermal) skin layer is seen to proliferate and become elongated.

Types of dermatitis include the following:

  • Atopic dermatitis is an inherited condition characterized by dry, sensitive, itchy skin. Infants and children are most affected, and the disorder can continue into adulthood.
  • Contact dermatitis is caused by an irritation or an allergy and occurs on areas of the skin that have come in contact with the identified substance. These reactions can be sudden and severe, such as with poison oak or poison ivy, or more insidious and chronic, such as from repeated exposure to harsh soaps or chemicals.
  • Seborrheic dermatitis is a fairly common condition seen mostly in adults and has a tendency to affect men more than women. The disease has a natural waxing and waning course. The cause is unknown.
  • Nummular dermatitis usually appears as stubborn, coin-shaped eczema plaques on the legs. It may be related to skin dryness, and moisturizers seem to help relieve the condition.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 01 Sep 2000

Last Modified: 07 Sep 2012