Psoriasis: Symptoms, Types, Causes, Triggers, Risk Factors, Diagnosis and Complications

Psoriasis is a chronic, inflammatory skin disease which is related to inherited genes. It causes cells to build up rapidly on the surface of the skin.

Updated: November 4, 2019

Psoriasis is a chronic, inflammatory skin disease which is related to inherited genes. It causes cells to build up rapidly on the surface of the skin. The extra skin cells form scales and red patches that are itchy and sometimes painful.
Mostly it affects the elbows, knees and scalp. It is not contagious. There is no cure for psoriasis, but symptoms can be managed.

Symptoms of Psoriasis:

Signs and symptoms of psoriasis are different for everyone. Common signs and symptoms include:

  • Red patches of skin covered with thick, silvery scales
  • Small scaling spots commonly seen in children
  • Dry, cracked skin that may bleed
  • Itching, burning or soreness
  • Thickened, pitted or ridged nails
  • Swollen and stiff joints

Psoriasis patches can range from a few spots of dandruff-like scaling to large, thick plaques to red inflamed skin affecting the entire body surface. Most types of psoriasis go through cycles. Flaring occurs for a few weeks or months and then subside for a time. These can even go into complete remission.These symptoms may worsen in the colder winter months.

Types of Psoriasis:

There are several types of psoriasis. These include:

Plaque psoriasis or psoriasis vulgaris:

This is the most common form of psoriasis which causes dry, raised, red skin lesions or plaques covered with silvery scales. The plaques may be few or many and might be itchy or painful. Mostly it affects skin over the elbows, knees, and scalp, but they can occur anywhere on your body, including your genitals and the soft tissue inside your mouth. Sometimes pulling off one of these small dry white flakes of skin causes a tiny blood spot on the skin. This is a special diagnostic sign in psoriasis called the Auspitz sign.

Nail psoriasis:

When Psoriasis affect fingernails and toenails, it causes pitting, abnormal nail growth and discoloration. Psoriatic nails might loosen and separate from the nail bed. Severe cases may cause the nail to crumble. Nail psoriasis may be confused with and incorrectly diagnosed as a fungal nail infection.

Guttate psoriasis:

Most commonly affects young adults and children. It is usually triggered by a bacterial infection such as strep throat. Signs include bumps or small plaques, water-drop-shaped, scaling lesions on your trunk, arms, legs and scalp.The lesions are not as thick as typical plaques and are covered by a fine scale. You may have a single outbreak that goes away on its own, or you may have repeated episodes.

Inverse psoriasis:

Skin in the armpits, in the groin, under the breasts, on the head of the penis and around the genitals are the most commonly affected areas in this type of psoriasis. Inverse psoriasis causes smooth patches of red, inflamed skin that worsen with friction and sweating. Fungal infections may trigger this type of psoriasis. Psoriasis in moist areas like the navel or the area between the buttocks may look like flat red plaques without much scaling. This may be confused with other skin conditions like fungal infections, yeast infections, allergic rashes, or bacterial infections.

Pustular psoriasis:

This type of psoriasis is very uncommon. This can either occur in widespread patches or in smaller areas on your hands, feet or fingertips. Widespread patches are called as generalized pustular psoriasis. It generally develops quickly. Rapid onset of groups of small bumps filled with pus called blisters appears just hours after your skin becomes red and tender. The blisters may come and go frequently. Generalized pustular psoriasis can also cause fever, chills, severe itching and diarrhea.

Erythrodermic psoriasis:

This is the least common type of psoriasis, which can affect your entire body with a red, peeling rash that can itch or burn intensely. Patients may often feel chilled.

Psoriatic arthritis:

Along with inflamed, scaly skin, psoriatic arthritis causes swollen, painful joints that are typical sign of arthritis. At times only nail changes are seen. Psoriatic arthritis can affect any joint and the symptoms range from mild to severe. It can cause stiffness and progressive joint damage which may lead to permanent deformity also.

Scalp psoriasis:

It may look like severe dandruff with dry flakes and red areas of skin. It can be difficult to differentiate between scalp psoriasis and seborrheic dermatitis when only the scalp is involved. However, the treatment is often very similar for both conditions.

Causes of Psoriasis:

The exact cause of Psoriasis is unknown. However it can be related to an immune system problem with T cells and other white blood cells, called neutrophils, in your body. T cells normally travel through the body to fight against foreign substances, such as viruses or bacteria. But the T cells attack healthy skin cells mistakenly if you have psoriasis.
Overactive T cells also trigger production of healthy skin cells, T cells and other white blood cells, especially neutrophils. When these travel into the skin, causes redness and sometimes pus in pustular lesions. Dilated blood vessels in psoriasis-affected areas create warmth and redness in the skin lesions.Therefore new skin cells move to the outermost layer of skin too quickly in days rather than weeks building up in thick, scaly patches on the surface of the skin.
This process will continue until treatment stops the cycle. The malfunction of T cells in people with psoriasis can be due to genetics and environmental factors.

Psoriasis triggers:

Factors that may trigger psoriasis include:

  • Infections, such as strep throat or skin infections
  • Injury to the skin, such as a cut or scrape, a bug bite, or a severe sunburn
  • Stress
  • Smoking
  • Heavy alcohol consumption
  • Vitamin D deficiency
  • Certain medications including lithium, which is prescribed for bipolar disorder, high blood pressure medications such as beta blockers, antimalarial drugs, and iodides

These factors will worsen the symptoms and therefore should be identified and avoided.

Risk factors:

Anyone can develop psoriasis, but the following factors can increase your risk of developing the disease:

Family history:

This is one of the most significant risk factors. Family history of psoriasis increases your risk of getting the disease.

Viral and bacterial infections:

People with HIV are more likely to develop psoriasis than people with healthy immune systems are. Children and young adults with recurring infections, particularly strep throat, also may be at increased risk.


Because stress can impact your immune system, high stress levels may increase your risk of psoriasis.


Being obese the risk of psoriasis increases. Plaques associated with all types of psoriasis often develop in skin creases and folds.


Smoking tobacco is another major risk factor for the disease. It not only increases your risk of psoriasis but also may increase the severity of the disease. Smoking may also play a role in the initial development of the disease.

Diagnosis of Psoriasis:

Diagnosis is based on physical examination and medical history. Your doctor usually can diagnose psoriasis by taking your medical history and examining your skin, scalp and nails.
Rarely, skin biopsy is done in which your doctor may take a small sample of skin after applying a local anesthetic. The sample is then examined under a microscope to determine the exact type of psoriasis and to rule out other disorders.

Is psoriasis contagious?

Directly touching someone with psoriasis will never transmit the disease. A person with psoriasis cannot pass it to anyone else by skin-to-skin contact. However there is a known hereditary tendency. Therefore, family history is very helpful in making the diagnosis.
Psoriasis is not currently curable. However, it can go into remission, producing an entirely normal skin surface. It can have periodic remissions and the remission period varies person to person.
Sometimes it can be difficult to differentiate eczematous dermatitis from psoriasis as both of these have similar sign and symptoms. But this can be done with the help of biopsy. Both eczematous dermatitis and psoriasis often respond to similar treatments. The only difference is certain types of eczematous dermatitis can be cured where this is not the case for psoriasis.
When psoriasis involve solely the nails, the nail signs accompany the skin and symptoms and signs of arthritis. Nail psoriasis is typically very difficult to treat and the treatment options are very limited.

Complications of Psoriasis:

You are at greater risk of developing the following diseases if you have psoriasis.

Psoriatic arthritis:

Patients may have inflammation of any joints (arthritis) when psoriasis is associated with inflamed joints. sometimes joint pains may be the only sign of the disorder, with completely clear skin.This complication of psoriasis can cause joint damage and a loss of function in some joints. Psoriatic arthritis is a destructive form of arthritis and needs to be treated with medications in order to stop the disease progression.

Eye disease:

Certain eye disorders such as conjunctivitis, blepharitis and uveitis are more common in people with psoriasis.


People with psoriasis, especially those with more severe disease, are more likely to be obese. The inflammation linked to obesity may play a role in the development of psoriasis. Because people with psoriasis are less active because of their disease, possibly they may gain weight.

Type 2 diabetes:

There is an increased risk of developing type 2 diabetes in people with psoriasis. The more severe the psoriasis, the greater the likelihood of type 2 diabetes.

High blood pressure:

The risk of having high blood pressure are higher for people with psoriasis.

Cardiovascular disease:

As psoriasis and some treatments increase the risk of irregular heartbeat, stroke, high cholesterol and atherosclerosis, the risk of cardiovascular disease is twice as high as it is for those without the disease.

Metabolic syndrome:

High blood pressure, elevated insulin levels and abnormal cholesterol levels can increase your risk of heart disease.

Other autoimmune diseases:

Certain autoimmune diseases such as Celiac disease, sclerosis and Crohn's disease can develop psoriasis in an individual.

Parkinson's disease:

This is a chronic neurological condition which is more likely to occur in people with psoriasis.

Kidney disease:

Moderate to severe psoriasis has been linked to a higher risk of kidney disease which can lead to kidney failure.

Emotional problems:

Psoriasis can also affect your quality of life. Psoriasis is associated with low self-esteem and depression. You may also withdraw socially because of depression.
Patients with psoriasis should be carefully monitored by their primary care providers for these associated illnesses. The joint inflammation of psoriatic arthritis and its complications are frequently managed by rheumatologists.

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