What is Psoriasis?
Psoriasis is chronic inflammatory skin disease characterized by areas of thickened, inflamed, itchy, red skin, often covered with silvery scales. It is considered an autoimmune disorder, in which the body's immune system becomes overactive and attacks itself, causing faster than normal skin cell turnover.
The normal skin cycle turnover – the time it takes your body to produce new skin cells and shed the old ones – is about a month. In people with psoriasis, production of new skin cells happens in just 3 to 4 days, but the old skin cells don't shed as quickly leading to a buildup of skin cells that results in thick, inflamed, red, flaky patches of skin called plaques.
Psoriasis is seen in equal rates in women and in men. Most often, psoriasis starts between the ages of 15 to 35, though it can develop at any time. Up to 15% of psoriasis cases are seen in children. Psoriasis is rare in babies.
What Causes Psoriasis?
There is a genetic basis for psoriasis. About 40% of people who have psoriasis have a family member with the disorder. It's this hereditary predisposition that causes the immune dysfunction where skin cell production accelerates.
Finally, the disease is triggered by environmental factors. Common environmental triggers for psoriasis include:
- Stress (physical or psychological)
- Skin injury or trauma (cuts, scrapes, insect bites, sunburn)
- Bacterial or viral infections (such as strep throat or thrush)
- Certain medications (common medications that trigger psoriasis flares include beta-blockers, antimalarials, inderal, lithium, quinidine, indomethacin)
- Excess alcohol
- Though not scientifically proven, some people with psoriasis report allergies, diet, and weather trigger their symptoms
What are Psoriasis Types?
There are multiple types of psoriasis, each with slightly different characteristics, symptoms, and appearance.
- Plaque psoriasis (the medical term for this type is "psoriasis vulgaris" - vulgaris means common) is the most common type of psoriasis, affecting about 80% of sufferers. Plaque psoriasis appears on the elbows and knees, the scalp, and lower back, and is characterized by raised, red, inflamed skin lesions, covered by thick silvery scales. It may also extend to the ears, belly button area, palms of the hands and soles of the feet, or the nails.
- Guttate psoriasis is the second-most common type of psoriasis, and often occurs in children or younger adults. Guttate means "drop-like," and this type of psoriasis is characterized by a sudden appearance of individual small (usually less than 1 cm in diameter), pink spots. These spots are scaly, but usually not as thick as plaque lesions seen in plaque psoriasis. The skin of the torso, extremities including arms, and legs are typically affected. There are some known triggers for guttate psoriasis, including recent streptococcal infection (strep throat).
- Inverse psoriasis, also called flexural psoriasis, is found in the folds of the skin such as the armpits, groin, under the breasts, and around the genitals and buttocks. Inverse psoriasis lesions are inflamed, bright red, smooth, and shiny. There is not usually scaling as seen with other types of psoriasis, such as plaque psoriasis. It tends to be seen more commonly in overweight people with more skin folds.
- Pustular psoriasis mostly affects adults and is characterized by white pustules (blisters of noninfectious pus which is made up of white blood cells) surrounded by red skin. Pustular psoriasis is neither an infection nor contagious. It can be either located on certain limited areas of the body, such as the hands and feet, or generalized where it covers most of the body. It tends to appear in cycles with skin redness first, followed by pustule formation, then skin scaling. Sometimes the pustules may crack. The generalized form of pustular psoriasis is a very rare and serious condition that often requires hospitalization. Symptoms of generalized pustular psoriasis include pustules covering most of the body, fever, chills, intense itching, rapid heart rate, exhaustion, headache, nausea, muscle weakness, and/or joint pain.
- Erythrodermic psoriasis (also called exfoliative psoriasis) is a rare type of psoriasis, and it can be severe and life threatening. Erythrodermic psoriasis usually covers most of the body's surface and is extremely inflammatory, characterized by bright red skin that may appear as a peeling rash, and shedding of scales in sheets. These flares (outbreaks) can be accompanied by pain and severe itching. In erythrodermic psoriasis the skin barrier is so weak patients are highly susceptible to infection (including cellulitis, which can lead to sepsis, a severe infection) and medical treatment must be sought immediately.
- Scalp psoriasis, as the name suggests, is when psoriasis forms on the scalp. This occurs in about 50% of people with psoriasis. It is characterized by redness and skin scaling that may affect the entire scalp, as well as your forehead, hairline, the back of your neck, or behind your ears. It can be mild, or severe with thick, crusted sores that are intensely itchy. Hair loss may also occur. It can be difficult to treat scalp psoriasis because the skin on the scalp is thicker, and hair gets in the way of topical treatments.
- Psoriasis of the nails can affect the fingernails and toenails. About half of psoriasis patients have abnormal nails, characterized by nail discoloration (yellow-red, also called an oil drop or salmon patch), pits in the nails, white areas on the nails (called leukonychia or midmatrix disease), skin thickening under the nail (subungual hyperkeratosis), loosening of the nail (onycholysis), horizontal lines that go across the nail (called Beau lines), redness of the half moon area at the base of the nail (called a spotted lunula), crumbling and brittle nails, and tiny black lines in the nail.
- Psoriatic arthritis affects about one-third of people with psoriasis. Psoriatic arthritis is a condition that causes joint pain, stiffness, and swelling. Most people develop the skin symptoms of psoriasis first, but about 15% will develop arthritis symptoms first. Patients with psoriatic arthritis also tend to have more severe nail symptoms. Early diagnosis and treatment of psoriatic arthritis is key to prevent joint damage.
What are Symptoms of Psoriasis?
Symptoms of psoriasis can be mild to severe, and can be in small, limited areas of the body such as the scalp, knees, elbows, hands and feet, or it can be widespread covering much of the body surface in including the face, arms, and legs. Psoriasis can come and go, with flares (worsening of the condition) and periods of remission (no symptoms). Symptoms can also vary depending on the type of psoriasis you have.
Common symptoms of psoriasis include:
- Dry, red, thick skin, covered by silvery scales
- Skin rashes
- Small pustular pink spots or bumps
- Bright red, smooth, and shiny rash in the folds of the skin
- Dry, flaky, peeling skin
- Skin cracks or fissures
- Painful lesions
- Joint pain, stiffness, or swelling
- Nail abnormalities such as dents or discoloration
- Depression may also occur
What is the Treatment for Psoriasis?
There are a number of different types of treatments for psoriasis.
- Topical medication such as lotions, foams, creams, ointments, gels, and shampoos applied directly to the skin is usually the first-line treatment for psoriasis. Types of topical medications to treat psoriasis include steroids, anthralin, synthetic vitamin D3, vitamin A, and calcium-modulating medications. Over-the-counter topicals include coal tar preparations and salicylic acid. Other products are used to moisturize or soothe the skin and may contain aloe vera, jojoba, zinc pyrithione, and capsaicin. When psoriasis is more widespread and covers more than 10% of the body surface, topical medications alone may not be as practical.
- Phototherapy, also called light therapy, exposes the skin to ultraviolet light (UVL) under medical supervision. Ultraviolet light (UVL) exposure treats larger areas of skin and is usually performed in a physician's office. The most commonly used type of UVL to treat psoriasis is called narrow-band UVB. Some types of lasers also produce UVL in wavelengths similar to narrow-band UVB, which can be effective for small areas of skin, but not widespread disease. This is not the same as indoor tanning beds, and the National Psoriasis Foundation does not recommend or endorse the use of tanning beds to treat psoriasis. A drawback of UVL treatments is that like all ultraviolet skin exposure it can lead to skin cancer.
- Systemic treatments (those that affect the whole body) are administered either orally or through the skin. Most types of systemic drugs for psoriasis target the immune system. Drugs in this class include apremilast (Otezla), methotrexate, and cyclosporine. Another systemic drug called acitretin (Soriatane) is similar to vitamin A and is also used to treat psoriasis.
- Biologics are a new class of drugs that are protein-based and synthesized by living cells. Biologics are given by injection or intravenous (IV) infusion and rather than affecting the entire immune system, they target specific parts of the immune system that cause the psoriasis symptoms. These types of medications include tumor necrosis factor-alpha (TNF-alpha) blockers [certolizumab pegol (Cimzia), etanercept (Enbrel), adalimumab (Humira), infliximab (Remicade), and golimumab (Simponi)], interleukin 17-A [secukinumab (Cosentyx) and ixekizumab (Taltz)], or interleukins 12 and 23 [ustekinumab (Stelara)].
- Alternative and home remedies are tried by many patients with psoriasis. There is limited scientific support for these alternative treatments, but many patients feel they are helped by natural remedies. Talk to your doctor before starting any home remedies, as some – especially herbal supplements – may interact with medications you are taking. Some examples of alternative and complementary remedies that may help ease psoriasis symptoms include:
Is Psoriasis Contagious?
Psoriasis is not contagious. It is not transmissible from person to person, and you cannot get psoriasis from touching a lesion on a person who has psoriasis. Psoriasis lesions, even pustular ones, are not infectious or contagious.
Can I Pass Psoriasis On To My Children?
While psoriasis is not contagious, it does have a genetic component, which means it can be inherited. About 40% of patients with psoriasis have a family history of the disease. However, just because you have psoriasis does not mean you will always pass it on to your children. If one parent has psoriasis, there is about a 10% chance of passing it on to offspring. If psoriasis affects both parents, there is a 50% chance of passing it on to their children.
What Is My Long-Term Prognosis With Psoriasis?
Psoriasis is a chronic immune disorder, and it cannot be cured. The prognosis for psoriasis depends on the type of psoriasis you have. Psoriasis tends to come and go, and it can be unpredictable. Patients may have periods of remission (no symptoms) followed by flares (worsening of symptoms). In some patients the disease is mild or moderate, in others it can be severe. Management of the symptoms of psoriasis is key to improving the quality of life of patients.
Plaque psoriasis, the most common type, will last for a person's lifetime and the symptoms can vary in severity. Guttate psoriasis may spontaneously go away or it can progress into chronic plaque psoriasis. Generalized pustular psoriasis, a rare but serious form of the illness, can be unstable.
Psoriasis rarely causes death, though erythrodermic psoriasis or generalized pustular psoriasis can be life-threatening if an infection develops.