Psoriasis
Definition of Psoriasis
Article updated and reviewed by Michael S. Lehrer, MD, Clinical Assistant Professor, Department of Dermatology, University of Pennsylvania. Editorial review provided by VeriMed Healthcare Network on April 18, 2005.Psoriasis is a common skin disease characterized by thickened patches of inflamed, red skin covered with thick, silvery scales. The elbows and knees are the most common areas affected by psoriasis. It will often appear in the same place on both sides of the body. The patches can range in size from smaller than a dime to larger than a hand.
Description of Psoriasis
Normally, skin cells mature and shed after about a month. In psoriasis, the cell maturation speeds up, taking only three to four days. Because the lower layer of skin cells divides more rapidly than normal, dead cells accumulate in thicker patches on the skin's outermost layer (called the epidermis). Forms and Classifications
Psoriasis occurs in a variety of forms that differ in their intensity, duration, location, shape and pattern of scales. The most common forms are:
Plaque psoriasis, or psoriasis vulgaris, is the most common form of psoriasis. It is characterized by raised, inflamed, red lesions covered with a silvery-white buildup of dead skin cells (scales). This is found primarily on the trunk, elbows, knees, scalp and finger or toe nails.
Pustular psoriasis is a rare form characterized by small pustules (whitehead-like lesions) found all over the body or confined to the palms, soles and other isolated areas of the body.
Guttate psoriasis occurs most frequently in children and is characterized by numerous small, red, drop-like scaly macules that develop rapidly over a wide area of skin. This may appear following an infection, most frequently Strep throat.
Inverse psoriasis occurs in the armpit, under the breast, in skin folds, around the groin, in the cleft between the buttocks and around the genitals. It is usually pink and irritated but lacks the thick scale seen in other forms of psoriasis.
Some dermatologists classify psoriasis as mild, moderate, or severe. Mild psoriasis is considered to be scaling over less than 5-10 percent of the body, moderate psoriasis is considered to be scaling over 10 to 20 percent of the body and severe psoriasis is considered to be scaling over 20 percent of the body.
In 5 percent of all psoriasis sufferers, arthritis will develop. This condition is called psoriatic arthritis. Arthritis is inflammation of a joint, usually accompanied by pain, swelling and changes in joint structure.
Causes and Risk Factors of Psoriasis
Psoriasis is a chronic skin disorder of unknown origin, however, heredity seems to play a role in susceptibility (1 in 3 people with psoriasis have an immediate relative with the disease). Psoriasis can be triggered by a number of factors, such as stress, climate changes, streptococcal or HIV infection, superficial wounds, physical illness, or taking certain drugs such as lithium, beta-blockers such as propranolol, quinidine (a heart medication) or antimalarial medications.
Diagnosis of Psoriasis
Dermatologists diagnose psoriasis by examining the skin and noting specific characteristics of the lesions. Occasionally they may need to biopsy the lesion and examine the skin under a microscope to confirm diagnosis. There are no blood tests or other laboratory tests available for establishing diagnosis.
Treatment of Psoriasis
There is no cure for psoriasis at this time, but there are various treatments that can, in most cases, temporarily clear the skin of psoriasis. Occasionally, psoriasis will go into spontaneous remission without treatment. For most patients, however, one or more of the following treatments is usually necessary: Topical Therapy (usually used to treat mild to moderate psoriasis):
- Emollients (moisturizers) help soften scales and reduce discomfort
- Steroid creams and ointments help reduce inflammation. They range in strength from very potent to mild. (See below)
- Tazarotene (Tazorac) is a topical retinoid for treating mild to moderate plaque psoriasis
- Anthralin or other coal tar preparations help to slow skin cell reproduction
- Vitamin D3 or calcipotriene (brand name Dovonex)
- Bath solutions, such as mineral salts or oatmeal additives, assist in soothing skin and encouraging healing
Phototherapy (used alone or in combination with other therapies to treat moderate to severe psoriasis):
- Ultraviolet Light B (UVB), either outdoors or from a light box in a physician's office, helps to heal lesions.
- Psoralen and Ultraviolet Light A (PUVA) - involves the combined use of a photosensitizing medication, called psoralen and a long-wave ultraviolet light (UVA).
- Excimer lasers may be used to treat a small, localized area of psoriasis. They are a way to deliver UVB light directly to the psoriasis without exposing normal skin.
Internal Medications (used for moderate to severe psoriasis):
- Biologic drugs are taken from living material (human, plant, animal, or microorganism). They act on parts of the body's immune system to prevent inflammatory disorders, including psoriasis. Unlike drugs that suppress the entire immune system, biologics can fight more selectively and target only those chemicals involved in causing psoriasis. Only recently have biologics targeted toward psoriasis begun to emerge as potentially promising new treatment options. Etanercept (Enbrel) and infliximab (Remicade) belong to the class of biologic medicines called tumor necrosis factor (TNF) blockers. These work by blocking the activity of TNF, the primary cytokine involved in psoriasis. Alefacept (Amevive) and efalizumab (Raptiva) are T-cell blockers and block the overactive T-cells. Unfortunately, each of these drugs requires frequent injections with needles. These medications are also relatively new and extremely expensive.
- Methotrexate (MTX) helps to slow down cell reproduction and decrease inflammation.
- Retinoid Therapy, including acitretin (Soriatane), helps to reduce inflammation.
- Cyclosporin A slows the immune system overall and may help decrease the inflammation of psoriasis.
Your dermatologist’s experience and trial and error will help to find which treatments are effective for each individual. Healing can take as little as a few weeks or as long as several months. Dermatologists may rotate patients through many different therapies to avoid long-term side effects and to determine which ones work best for that individual.
Self Care
- Keep skin lubricated. Oils, creams and petroleum jelly preparations are suggested.
- Use a humidifier in the home.
- Get out in the sun. Be careful not to burn. Exposing only the areas of your body with active psoriasis may be optimal.
- Bathing in hot water may help reduce scaling.
- Use mild soaps or soap-free cleaners. Mild soaps such as Nivea Cream, Neutrogena Dry Skin, Dove, or Lever 2000 are recommended.
- Minimize stress.
- Protect against skin injuries and skin infections.
Topical Steroids
The following is a partial list of topical steroids used to treat eczema.
Very potent:
Betamethasone dipropionate (Diprolene)
Clobetasol 17-Propionate 0.05% (Temovate)
Halobetasol propionate (Ultravate)
Halcinonide 0.1% (Halog)
Potent:
Amcinonide 0.1% (Cyclocort)
Betamethasone dipropionate 0.5 mg (Diprolene)
Desoximetasone 0.25% (Topicort)
Fluocinonlone acetonide 0.25% (Synalar)
Fluocinonide 0.05% (Lidex)
Mometasone furoate 0.1% (Elocon)
Triamcinolone Acetonide 0.1% (Kenalog)
Moderately potent:
Desonide 0.05% (Desowen)
Hydrocortisone valerate 0.2% (Westcort)
Prednicarbate 0.1% (Dermatop)
Mild:
Hydrocortisone 1.0% (Cortaid)
Questions To Ask Your Doctor About Psoriasis
What form of psoriasis is this?
How severe is the psoriasis?
Can it increase in severity or spread?
What are the chances that another rheumatic disease may develop?
What type of treatment will you be recommending?
What measures can be taken to help prevent reoccurrence?
If over-the-counter lotions are recommended, which ones seem to be most effective?
If a biopsy is recommended, what will the result tell you?
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