Psoriasis is a noncontagious common skin condition that causes rapid skin cell reproduction resulting in red, dry patches of thickened skin. The dry flakes and skin scales are thought to result from the rapid buildup of skin cells. Psoriasis commonly affects the skin of the elbows, knees, and scalp.
Some people have such mild psoriasis (small, faint dry skin patches) that they may not even suspect that they have a medical skin condition. Others have very severe psoriasis where virtually their entire body is fully covered with thick red, scaly skin.
Psoriasis is considered a non-curable, long-term (chronic) skin condition. It has a variable course, periodically improving and worsening. Sometimes psoriasis may clear for years and stay in remission. Some people have worsening of their symptoms in the colder winter months. Many people report improvement in warmer months, climates, or with increased sunlight exposure.
Psoriasis is seen worldwide, in all races, and both sexes. Although psoriasis can be seen in people of any age, from babies to seniors, most commonly patients are first diagnosed in their early adult years.
Patients with more severe psoriasis may have social embarrassment, job stress, emotional distress, and other personal issues because of the appearance of their skin.
The exact cause remains unknown. There may be a combination of factors, including genetic predisposition and environmental factors. It is common for psoriasis to be found in members of the same family. The immune system is thought to play a major role. Despite research over the past 30 years looking at many triggers, the "master switch" that turns on psoriasis is still a mystery.
Psoriasis typically looks like red or pink areas of thickened, raised, and dry skin. It classically affects areas over the elbows, knees, and scalp. Essentially any body area may be involved. It tends to be more common in areas of trauma, repeat rubbing, use, or abrasions.
Psoriasis has many different appearances. It may be small flattened bumps, large thick plaques of raised skin, red patches, and pink mildly dry skin to big flakes of dry skin that flake off.
There are several different types of psoriasis including psoriasis vulgaris (common type), guttate psoriasis (small, drop like spots), inverse psoriasis (in the folds like of the underarms, navel, and buttocks), and pustular psoriasis (liquid-filled yellowish small blisters). Additionally, a separate entity affecting primarily the palms and the soles is known as palmoplantar psoriasis
Eczema is a general term for many types of skin inflammation, also known as dermatitis. The most common form of eczema is atopic dermatitis (some people use these two terms interchangeably). However, there are many different forms of eczema.
Eczema can affect people of any age, although the condition is most common in infants. Eczema will permanently resolve by age 3 in about half of affected infants. In others, the condition tends to recur throughout life. People with eczema often have a family history of the condition or a family history of other allergic conditions, such as asthma or hay fever. Up to 20% of children and 1%-2% of adults are believed to have eczema.
Doctors do not know the exact cause of eczema, but an abnormal function of the immune system is believed to be a factor. Some forms of eczema can be triggered by substances that come in contact with the skin, such as soaps, cosmetics, clothing, detergents, jewelry, or sweat. Environmental allergens (substances that cause allergic reactions) may also cause outbreaks of eczema. Changes in temperature or humidity, or even psychological stress, for some people lead to outbreaks of eczema.
Eczema most commonly causes dry, reddened skin that itches or burns, although the appearance of eczema varies from person to person and varies according to the specific type of eczema. Intense itching is generally the first symptom in most people with eczema. Sometimes, eczema may lead to blisters and oozing lesions, but eczema can also result in dry and scaly skin. Repeated scratching may lead to thickened, crusty skin.
While any region of the body may be affected by eczema, in children and adults, eczema typically occurs on the face, neck, and the insides of the elbows, knees, and ankles. In infants, eczema typically occurs on the forehead, cheeks, forearms, legs, scalp, and neck.
Eczema can sometimes occur as a brief reaction that only leads to symptoms for a few hours or days, but in other cases, the symptoms persist over a longer time and are referred to as chronic dermatitis.