It is thought to happen when the immune system mistakenly starts producing skin cells too quickly.
It affects men and women equally. It can begin at any age, but it is most common between the ages of 15 and 35 years, and again between 50 and 60 years. The average age is 28 years.
Around 15 percent of cases emerge before the age of 10 years.
Plaque psoriasis is the most common type of psoriasis.
Skins cells shed all the time, but in psoriasis, both dead and live cells collect on the skin's surface, because the replacement process is so fast.
The main symptoms of psoriasis are:
- red, flaky, crusty patches, covered with silvery scales that shed easily
- intense itching and burning
However, symptoms can differ, according to the type. Severity can range from mild to severe.
According to the National Psoriasis Foundation:
- mild psoriasis covers less than 3 percent of the body
- moderate psoriasis affects between 3 and 10 percent
- severe psoriasis covers over 10 percent of the body.
Around 80 percent of people have mild psoriasis, and the other 20 percent have moderate to severe psoriasis.
Psoriasis can affect any part of the body, but it mostly appears as small patches on the elbows, knees, lower back, and scalp.
There are several forms of psoriasis.
About 80 to 90 percent of people with psoriasis have plaque psoriasis. It appears as raised, inflamed, red lesions, covered by a silvery, white scales, usually on the elbows, knees, scalp, and lower back.
Inverse psoriasis appears in the armpits, the groin, under the breasts, and in other skin folds such as around the genitals, and the buttocks. It first appears as red lesions, usually without the scale associated with plaque psoriasis. It may appear smooth and shiny.
Irritation from rubbing and sweating can make it worse, because of its location in skin folds and tender areas. It is more common in people who are overweight and in those with deep skin folds. It can affect the genital area.
Erythrodermic psoriasis is a particularly inflammatory form that can affect large parts of the body surface with a fiery redness. Erythema means reddening.
It generally appears on people with unstable plaque psoriasis, where lesions are not clearly defined. There may also be exfoliation, or shedding of the skin, severe itching, and pain.
Erythrodermic psoriasis is linked to an imbalance in the body's homeostasis. This can cause protein and fluid loss that can lead to severe illness.
The complications of erythrodermic psoriasis can be life threatening. Anyone who may have symptoms of this condition should see a doctor at once.
People with severe cases of this condition may spend time in the hospital.
Guttate psoriasis often starts in childhood or young adulthood. It appears as small, red, individual spots on the skin that are not normally as thick or as crusty as the lesions in plaque psoriasis.
A range of conditions can trigger it, including upper respiratory infections, streptococcal infections, tonsillitis, stress, injury to the skin, and the use of certain drugs, including antimalarials, lithium, and beta-blockers.
This form of psoriasis may go away on its own and not come back, or it may clear for a time and reappear later as patches of plaque psoriasis.
Pustular psoriasis affects adults more than children, and it accounts for fewer than 5 percent of psoriasis cases.
It appears as white pustules, or blisters, of non-infectious pus, surrounded by red skin. It can affect certain areas of the body, for example, the hands and feet, or most of the body. It is not an infection, and it is not contagious.
Pustular psoriasis tends to follow a cycle, in which reddening of the skin is followed by the formation of pustules and scaling.
This causes inflammation and progressive damage to the joints. It is most common between the ages of 30 to 50 years.
People with psoriatic disease commonly experience social exclusion and low self-esteem. Together with the physical discomfort, itching, and pain of psoriasis, this can impact their quality of life.
Maybe as a result of these factors, psoriasis has been linked to depression.
Psoriasis has also been linked to a higher risk of cardiovascular disease and other health conditions.
Psoriasis is an autoimmune disease. It happens when a problem occurs with the immune system.
The immune system involves a type of cells known as T cells. A trigger causes the T cells to behave as if they are fighting an infection or healing a wound. They produce chemicals that cause inflammation.
In psoriasis, this leads to an excessive growth of skin cells and inflammation.
Normally, skin cells take about 21 to 28 days to replace themselves, but, in patients with psoriasis, they take around 2 to 6 days.
Medications that can trigger it include lithium, antimalarials, quinidine, and indomethacin. Some people associate psoriasis with allergies, diet, and weather, but this is not proven.
It is not contagious.
Some factors increase the likelihood of developing psoriasis.
- having cardiovascular disease and metabolic syndrome
- trauma to the skin
- family history
About 1 in 3 people with one close relative with psoriasis will develop the condition. If one parent has psoriasis, there is a 10 percent chance of developing it, and if both parents have it, the chance is 50 percent.
This suggests an underlying genetic component, but the disease may not emerge unless an environmental factor triggers it to become active. At least 10 percent of the population are thought to have the gene that causes psoriasis, but only 2 to 3 percent of people develop it.
Among younger people, psoriasis may appear after an infection, notably strep throat. Between 33 and 50 percent of young people with psoriasis will notice a flare-up between 2 and 6 weeks following an earache or a respiratory infection such as strep throat, bronchitis, or tonsillitis.
A person who has a persistent rash that does not go away with over-the-counter (OTC) treatment should consider asking a doctor about it.
The doctor will look at the symptoms and ask about personal and family history, and they may carry out a skin biopsy.
There are no blood tests for psoriasis.
If a diagnosis is confirmed, treatment will depend on the type and severity of the condition. The main options include topical therapy, systemic therapy, and phototherapy.
Topical treatment is applied directly to the skin. It is usually the first line of treatment, and the aim is to slow down the growth of skin cells and reduce inflammation. These treatments are available over the counter (OTC) or on prescription, and include non-steroids and steroids.
To help reduce itching, the following are available:
- A keratolytic product can help remove flaking skin. OTC options may contain salicylic acid, lactic acid, urea, or phenol.
- OTC products, such as calamine, hydrocortisone, camphor, diphenhydramine hydrochloride (HCl), benzocaine, and menthol, may help, but these can also dry the skin. The individual should see what works best.
Systemic therapies work through the body system. Some affect the whole system, and they are used for people with moderate to severe psoriasis and psoriatic arthritis. These are taken by mouth or by injection, and they include acitretin, cyclosporine, and methotrexate.
Biologic drugs are a type of systemic therapy. A biologic is a protein-based drug that is made from living cells grown in a laboratory. Biologics target the specific T cells that are associated with psoriasis.
Phototherapy is light therapy. The skin is exposed regularly to ultraviolet light, either in the doctor's office or at home. This is done under medical supervision. Tanning beds are not recommended as a substitute.
It is not possible to avoid psoriasis, but some strategies can help people to cope with it.
- lowering stress by doing yoga, exercise, meditation or both
- getting a balanced diet and maintaining a healthy weight
- recognizing and avoiding food triggers
- joining a support group or blog to talk with others with a similar experience
- not smoking or drinking alcohol excessively
Home remedies for reducing itching include:
- Keeping the skin moisturized: A dermatologist can recommend a suitable product
- Taking a cold shower for up to 10 minutes, or using a cold pack: Avoid hot showers, as they can dry the skin