(Source: National Psoriasis Foundation) Psoriasis is a chronic, autoimmune disease that appears on the skin. It occurs when the immune system sends out faulty signals that speed up the growth cycle of skin cells. Psoriasis is not contagious. There are five types of psoriasis. The most common form, plaque psoriasis, appears as raised, red patches covered with a silvery white buildup of dead skin cells. Psoriasis can occur on any part of the body and is associated with other serious health conditions, such as diabetes, heart disease and depression. Psoriasis is the most common autoimmune disease in the U.S. As many as 7.5 million Americans have psoriasis.
Psoriasis appears in a variety of forms with distinct characteristics. Typically, an individual has only one type of psoriasis at a time. Generally, one type of psoriasis will clear and another form of psoriasis will appear in response to a trigger.
Psoriasis causes and known triggers
Scientists believe that at least 10 percent of the general population inherits one or more of the genes that create a predisposition to psoriasis. However, only 2 percent to 3 percent of the population develops the disease. Researchers believe that for a person to develop psoriasis, the individual must have a combination of the genes that cause psoriasis and be exposed to specific external factors known as "triggers".
Psoriasis triggers are not universal. What may cause one person's psoriasis to become active, may not affect another.
Established psoriasis triggers include:
Stress can cause psoriasis to flare for the first time or aggravate existing psoriasis. Relaxation and stress reduction may help prevent stress from impacting psoriasis.
Injury to skin
Psoriasis can appear in areas of the skin that have been injured or traumatized. This is called the Koebner [KEB-ner] phenomenon. Vaccinations, sunburns and scratches can all trigger a Koebner response. The Koebner response can be treated if it is caught early enough.
Certain medications are associated with triggering psoriasis, including:
- Lithium: Used to treat manic depression and other psychiatric disorders. Lithium aggravates psoriasis in about half of those with psoriasis who take it.
- Antimalarials: Plaquenil, Quinacrine, chloroquine and hydroxychloroquine may cause a flare of psoriasis, usually 2 to 3 weeks after the drug is taken. Hydroxychloroquine has the lowest incidence of side effects.
- Inderal: This high blood pressure medication worsens psoriasis in about 25 percent to 30 percent of patients with psoriasis who take it. It is not known if all high blood pressure (beta blocker) medications worsen psoriasis, but they may have that potential.
- Quinidine: This heart medication has been reported to worsen some cases of psoriasis.
- Indomethacin: This is a nonsteroidal anti-inflammatory drug used to treat arthritis. It has worsened some cases of psoriasis. Other anti-inflammatories usually can be substituted. Indomethacin's negative effects are usually minimal when it is taken properly. Its side effects are usually outweighed by its benefits in psoriatic arthritis.
Other psoriasis triggers
Although scientifically unproven, some people with psoriasis suspect that allergies, diet and weather trigger their psoriasis. Strep infection is known to trigger guttate psoriasis.
Types of psoriasis
Plaque Psoriasis (psoriasis vulgaris)
Plaque psoriasis is the most common form of the disease and appears as raised, red patches covered with a silvery white buildup of dead skin cells or scale. These patches or plaques most often appear on the scalp, knees, elbows and lower back. They are often itchy and painful, and they can crack and bleed.
Guttate [GUH-tate] psoriasis is a form of psoriasis that often starts in childhood or young adulthood. This is the second most common type of psoriasis, after plaque psoriasis. About 10 percent of people who get psoriasis develop guttate psoriasis.
Inverse psoriasis (also known as intertriginous psoriasis) shows up as very red lesions in body folds. It may appear smooth and shiny. Many people have another type of psoriasis elsewhere on the body at the same time.
Pustular [PUHS-choo-lar] psoriasis in characterized by white pustules (blisters of noninfectious pus) surrounded by red skin. The pus consists of white blood cells. It is not an infection, nor is it contagious.
Erythrodermic [eh-REETH-ro-der-mik] psoriasis is a particularly inflammatory form of psoriasis that often affects most of the body surface. It may occur in association with von Zumbusch pustular psoriasis. It is a rare type of psoriasis, occurring once or more during the lifetime of 3 percent of people who have psoriasis. It generally appears on people who have unstable plaque psoriasis. This means the lesions are not clearly defined. Widespread, fiery redness and exfoliation of the skin characterize this form. Severe itching and pain often accompanies it.
NOTE: Individuals having an erythrodermic psoriasis flare should see a doctor immediately. This form of psoriasis can be life-threatening.
Source: National Psoriasis Foundation
Key Point 1
Psoriasis is a chronic, autoimmune disease for many beginning in childhood with strong genetic pre-dispositions. An outbreak is often triggered by injury to the skin or stress or medication and even though psoriasis is not contagious, patients often feel stigmatized by the disease.
Key Point 2
Effective treatment for psoriasis can be challenging, skin can become resistant to treatment over time and more powerful medications have serious side effects sometimes. Treatment for the individual may change throughout lifetime, it’s important to talk to your doctor about your options but the bottom line is there are great treatments now and more on the way.