What is Psoriasis?

Psoriasis is a chronic, hereditary, noncontagious skin disorder characterized by scaling and inflammation that can develop on virtually any part of the body, even the nails and scalp. There are five main types of psoriasis (plaque, pustular, erythrodermic, guttate or inverse) with varying symptoms and levels of severity ranging from mild to severe. The level of severity is determined by the amount of coverage of the patient’s body and how it affects their quality of life (QoL). A dermatologist can help you determine what type of psoriasis you have.

What causes psoriasis?

Psoriasis is a skin disorder that is closely linked to the immune system. The immune systems T-cells main purpose is to fight off infection, but a malfunction of the immune system can cause the T-cells to react differently inciting the skin to produce skin cells too rapidly. In unaffected skin the normal cycle of skin cell production runs on a 28 to 30 day cycle. Skin affected by psoriasis produces new skin cells every 6 to 8 days thus not allowing enough time for the older cells to dry up and slough off naturally. This is where the formation of painful plaques begins. Researchers have found that many people who have psoriatic symptoms come from a family history of psoriasis. Inheritance seems to play a large role in the development of the disease. People with psoriasis may notice that they experience periods when the condition is worse and then it improves. The skins reactions many times are tempered by changes in stress, climate, or infection. Also, there are certain medications that may aggravate the condition.

How is psoriasis diagnosed?

Occasionally, doctors may find it difficult to diagnose psoriasis, because it often looks like other skin diseases. It may be necessary to confirm a diagnosis by examining a small skin sample under a microscope. 

What does psoriasis look like?

There are five types of psoriasis. Each has its own unique signs (what is seen) and symptoms (what is felt by the person).

Plaque psoriasis

About 80% of people living with psoriasis have plaque psoriasis, which also is called “psoriasis vulgaris.” “Vulgaris” means “common.” 

How to recognize plaque psoriasis:

• Raised and thickened patches of reddish skin, called “plaques,” which are covered by silvery-white scales. 
• Plaques most often appear on the elbows, knees, scalp, chest, and lower back. However, they can appear anywhere on the body, including the genitals.
• Plaques vary in size and can appear as distinct patches or join together to cover a large area.
• In the early stages, the psoriasis may be unnoticeable. The skin may itch and/or a burning sensation may be present.
• Plaque psoriasis usually first appears as small red bumps. Bumps gradually enlarge, and scales form. While the top scales flake off easily and often, scales below the surface stick together. The small red bumps develop into plaques (reddish areas of raised and thickened skin).
• Skin discomfort. The skin is dry and may be painful. Skin can itch, burn, bleed, and crack. In severe cases, the discomfort can make it difficult to sleep and focus on everyday activities.

Guttate psoriasis

About 10% of people who get psoriasis develop guttate psoriasis, making this the second most common type. Guttate psoriasis most frequently develops in children and young adults who have a history of streptococcal (strep) infections. A mild case of guttate psoriasis may disappear without treatment, and the person may never have another outbreak of psoriasis. Some children experience flare-ups for a number of years. It also is possible for the psoriasis to appear later in life as plaque psoriasis. In some cases, guttate psoriasis is severe and disabling, and treatment may require oral medication or injections. 

How to recognize guttate psoriasis:

• Drop-sized, red dots form — usually on the trunk, arms, and legs. Lesions occasionally form on the scalp, face, and ears.
• Lesions widespread.
• Appears quickly, usually a few days after a strep throat or other trigger, such as a cold, tonsillitis, chicken pox, skin injury, or taking certain medications.
• Can first appear as another form of psoriasis, such as plaque psoriasis, and turn into guttate psoriasis.

Pustular psoriasis

This type of psoriasis occurs in less than 5% of people who develop psoriasis and primarily occurs in adults. It may be the first sign of psoriasis or develop from plaque psoriasis. Pustular psoriasis can be triggered by infections, sunburn, or medications such as lithium and systemic cortisones. There are two forms of pustular psoriasis: localized and generalized. 

How to recognize localized pustular psoriasis:

• Psoriasis confined to certain areas (localized), usually the palms and soles. This is known as “palmoplantar psoriasis.”
• Skin red, swollen, and dotted with pus-filled lesions.
• Pus-filled lesions dry, leaving behind brown dots and/or scale.
• Affected areas tender and sore. Using hands or walking often painful.
• Attacks of pustular psoriasis may be triggered by medications, infections, stress, or exposure to certain chemicals.

Generalized pustular psoriasis

This is a rare and severe form of psoriasis that can be life-threatening, especially for older adults. Hospitalization may be required. Generalized pustular psoriasis may be triggered by an infection such as strep throat, suddenly stopping steroids, pregnancy, and taking certain medications such as lithium or systemic cortisone. 

How to recognize generalized pustular psoriasis:

• Widespread areas of fiery-red swollen skin covered with small, white, pus-filled blisters
• Person feels exhausted and ill
• Fever
• Chills
• Severe itching
• Rapid pulse rate
• Loss of appetite
• Muscle weakness
• Anemia

Inverse psoriasis

Not common, inverse psoriasis also is called “skin-fold,” “flexural,” or “genital” psoriasis. This type of psoriasis can be severe and incapacitating. 

How to recognize inverse psoriasis:

• Red and inflamed plaques that only occur in skin folds — armpits, in the genital area, between the buttocks, and under the breasts.
• Scale usually does not form, and the lesions are shiny and smooth.
• Skin very tender.
• Lesion easily irritated, especially by rubbing and perspiration.
• More prevalent in people who are overweight.
• Many people have another type of psoriasis elsewhere on the body.

Erythrodermic psoriasis

Also known as “exfoliative” psoriasis, this is the least common type. It occurs in about 1% or 2% of people who develop psoriasis. Erythrodermic psoriasis can be life-threatening because the skin loses its protective functions. The skin may not be able to safeguard against heat and fluid loss nor prevent harmful bacteria and other substances from entering the body. Patients are usually hospitalized and given intravenous fluids. Body temperature regulation may be required. Erythrodermic psoriasis may occur suddenly in a person who has never had psoriasis or evolve from plaque psoriasis. Triggers include infection, emotional stress, alcoholism, and certain medications such as lithium, anti-malarial drugs, and a strong coal tar preparation. It also may be triggered by excessive use of potent corticosteroids, which is why it is important to use corticosteroids as instructed. Suddenly stopping a psoriasis medication, such as cyclosporine or methotrexate, also can trigger erythrodermic psoriasis. 

How to recognize erythrodermic psoriasis:

• Severe redness and shedding of the skin that covers a large portion of the body.
• Skin looks as if it has been burned.
• Fluctuating body temperature, especially on very hot or cold days.
• Accelerated heart rate due to increased blood flow to the skin — can complicate heart disease and cause heart failure.
• Severe itching and pain.

Is there a cure?

Psoriasis is a chronic disease. While most people with this skin condition are able to maintain a high quality of life there is no cure. Treatment means clearing or alleviating symptoms for a period of time. The key is finding the treatment option that is best for you. There are many choices available for the treatment of psoriasis. Some options are new, their risks and effectiveness unknown. Others are time-tested, proven to be effective, and their safety well established. Phototherapy has long been the option of choice for thousands of physicians and tens of thousands of patients around the globe. Whether used independently or in combination with a complementary agent, such as psoralen used with UVA (know as PUVA), phototherapy is the most trusted option available.

Light therapy

Natural ultraviolet light from the sun and controlled delivery of artificial ultraviolet light are used in treating psoriasis.

• Sunlight. Much of sunlight is composed of bands of different wavelengths of ultraviolet (UV) light. When absorbed into the skin, UV light suppresses the process leading to disease, causing activated T cells in the skin to die. This process reduces inflammation and slows the turnover of skin cells that causes scaling. Daily, short, nonburning exposure to sunlight clears or improves psoriasis in many people. Therefore, exposing affected skin to sunlight is one initial treatment for the disease.
• Ultraviolet B (UVB) phototherapy. UVB is light with a short wavelength that is absorbed in the skin’s epidermis. An artificial source can be used to treat mild and moderate psoriasis. Some physicians will start treating patients with UVB instead of topical agents. A UVB phototherapy, called broad band UVB, can be used for a few small lesions, to treat widespread psoriasis, or for lesions that resist topical treatment. This type of phototherapy is normally given in a doctor’s office by using a light panel or light box. Some patients use UVB light boxes at home under a doctor’s guidance.
• Narrowband UVB. A newer type of UVB, called narrow band UVB, emits the part of the ultraviolet light spectrum band that is most helpful for psoriasis. Narrowband UVB treatment is superior to broad band UVB, but it is less effective than PUVA treatment (see next paragraph). It is gaining in popularity because it does help and is more convenient than PUVA. At first, patients may require several treatments of narrow band UVB spaced close together to improve their skin. Once the skin has shown improvement, a maintenance treatment once each week may be all that is necessary. However, narrow band UVB treatment is not without risk. It can cause more severe and longer lasting burns than broad band treatment.
• Psoralen and ultraviolet A phototherapy (PUVA). This treatment combines oral or topical administration of a medicine called psoralen with exposure to ultraviolet A (UVA) light. UVA has a long wavelength that penetrates deeper into the skin than UVB. Psoralen makes the skin more sensitive to this light. PUVA is normally used when more than 10 percent of the skin is affected or when the disease interferes with a person’s occupation (for example, when a teacher’s face or a salesperson’s hands are involved). Compared with broad band UVB treatment, PUVA treatment taken two to three times a week clears psoriasis more consistently and in fewer treatments. However, it is associated with more shortterm side effects, including nausea, headache, fatigue, burning, and itching. Care must be taken to avoid sunlight after ingesting psoralen to avoid severe sunburns, and the eyes must be protected for one to two days with UVA-absorbing glasses. Long-term treatment is associated with an increased risk of squamous-cell and, possibly, melanoma skin cancers. Simultaneous use of drugs that suppress the immune system, such as cyclosporine, have little beneficial effect and increase the risk of cancer.
• Light therapy combined with other therapies. Studies have shown that combining ultraviolet light treatment and a retinoid, like acitretin, adds to the effectiveness of UV light for psoriasis. For this reason, if patients are not responding to light therapy, retinoids may be added. UVB phototherapy, for example, may be combined with retinoids and other treatments. One combined therapy program, referred to as the Ingram regime, involves a coal tar bath, UVB phototherapy, and application of an anthralin-salicylic acid paste that is left on the skin for 6 to 24 hours. A similar regime, the Goeckerman treatment, combines coal tar ointment with UVB phototherapy. Also, PUVA can be combined with some oral medications (such as retinoids) to increase its effectiveness.

Where can I find more information?

Many of these support organizations can provide additional information about this condition.

References

What is Psoriasis. National Institute of Arthritis and Musculoskeletal and Skin Diseases. https://www.niams.nih.gov/health-topics/psoriasis. Published May 1, 2003.

What Psoriasis Looks Like. American Academy of Dermatology. http://www.skincarephysicians.com/psoriasisnet/looks_like.html. Published August 18, 2005.