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.

1 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. There are several forms
of psoriasis. Some of these include:

2 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:

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:

  • 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:

    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:

    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:

    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:

    An educational program brought to you by the American Academy of Dermatology.


    Is there a cure for psoriasis?

    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.

    What are the available psoriasis treatments? 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.

    3 Light Therapy

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

    Where can I find more information about psoriasis & available treatments?

    National Institute of Arthritis and Musculoskeletal and
    Skin Diseases
    NIAMS/National Institutes of Health
    1 AMS Circle
    Bethesda, MD 20892-3675
    Phone: 301-495-4484
    TTY: 301-565-2966
    Fax: 301-718-6366

    American Academy of Dermatology
    P.O. Box 4014
    Shaumburg, IL 60168-4014
    Phone: 847-330-0230 or 888-462-DERM (3376) (free of charge)
    Fax: 847-330-0050

    National Psoriasis Foundation
    6600 SW 92nd Avenue, Suite 300
    Portland, OR 97223-7195
    Phone: 503-244-7404 or 800-723-9166 (free of charge) Fax: 503-245-0626

    Medline Plus

    A service of the U.S. National Library of Medicine

    and the National Institutes of Health

    U.S. National Library of Medicine

    8600 Rockville Pike

    Bethesda, MD 20894
    Toll Free: (888) FIND-NLM
    (888) 346-3656
    Phone: (301) 594-5983 (local and international calls)
    Fax: (301) 402-1384
    ILL Fax: (301) 496-2809

    1, 3 Questions and Answers about Psoriasis. National Institute of Arthritis and Musculoskeletal and Skin Diseases and National Institute of Health, May 2003.

    2 What Psoriasis Looks Like. American Academy of Dermatology, August 18, 2005.