Sometimes called dermatitis, eczema refers to a variety of persistent or chronic skin conditions that involve inflammation of the upper layers of the skin. Despite its sometimes unsightly appearance, eczema is not contagious. Eczema is one of the most frequently diagnosed skin disorders worldwide and, as a result, it's often seen as a minor dermatological condition. But the reality is that, due to its chronic recurrence, eczema can often be very difficult to treat. The inflammation and other symptoms of eczema can be managed with appropriate treatment, but the skin will always be susceptible to flare-ups and require extra care.

Eczema usually occurs as one of four common types:

• Atopic eczema (also known as atopic dermatitis) may have a genetic component and be found in families whose members suffer from hay fever and asthma. It is especially noticeable as an itchy rash on the face and scalp, neck, inside the elbows, behind the knees, and buttocks. In developed countries it is frequently mistaken for contact dermatitis.
   
• Contact dermatitis occurs in two forms:
  • Allergic – usually a delayed reaction to an allergen like poison ivy or nickel (often found in earrings);
  • Irritant – (most common) a more direct reaction to a solvent like sodium lauryl sulfate; this is the most common occupational skin disease.
     
• Xerotic eczema (also called asteatotic eczema or craquele or craquelatum, winter itch, or pruritus hiemalis) begins as dry skin that becomes so severe that it turns into eczema with the limbs and trunk being affected most. Dry winter weather exacerbates the condition. In xerotic eczema the skin can look like a dry, cracked, river bed and be very itchy and tender. This form of eczema occurs most commonly among the elderly.
   
• Seborrhoeic dermatitis (also called cradle cap in infants, dandruff) produces dry or greasy scaling in the scalp and eyebrows. The condition can also produce scaly pimples and red patches in nearby areas. The thick, yellow, crusty scalp rash called cradle cap in newborns may be related to a lack of biotin and is usually curable.

• Dyshidrosis is typically seen on palms, soles, and sides of fingers and toes with tiny opaque bumps (vesicles), thickening, and cracks that itch, most especially at night; warm weather makes the condition worse.
   
• Discoid eczema most often occurs on the lower legs as round spots of oozing or dry rash; the cause of this intermittent disease is unknown.
   
• Venous eczema is most commonly seen in people over 50 with poor circulation, varicose veins, and edema (swelling) and is characterized by redness, scaling, and darkening of the skin as well as itching.
   
• Dermatitis herpetiformis is directly related to celiac disease (an autoimmune intestinal disorder) and is an intensely itchy and usually symmetrical rash on the arms, thighs, knees, and back. This form of eczema can be put into remission by adjusting the diet appropriately.
   
• Neurodermatitis develops when persistent scratching irritates nerve endings and causes persistent inflammation. Anti-inflammatory medication and behaviour modification, that is, stopping the habitual scratching, usually provides a cure.
   
• Autoeczematization occurs as a result of an infection by parasites, fungi, bacteria, or viruses. Eradication of the initial infection can produce a complete cure. The appearance of autoeczematization will depend on its cause; it always appears some distance from the initial infection.