Psoriasis: Types, Causes, Symptoms and Treatment Options
Psoriasis is a common skin disorder characterized by raised, inflamed lesions that join together to form plaques (patches) with clearly defined borders that are covered with flaky scales. This chronic, non-contagious skin condition can affect any part of the body and is often related to hereditary factors.
Psoriasis is highly variable. In some patients it may be no more than a minor cosmetic problem, while in others it can cause quite serious problems with many remissions and flares. However, most cases are mild to moderate. Severe cases of psoriasis may lead to secondary infections as well as fluid loss resulting in poor blood flow. Furthermore, patients undergoing treatments for severe psoriasis may experience adverse side effects from the medications used.
The rapid turnover of cells in the epidermis that characterizes psoriasis is believed to be caused by a faulty immune system. Psoriasis is therefore considered to be an autoimmune disease. Normal healthy skin cells mature in about one month whereas in psoriasis new cells are produced, grow to maturity and die far too quickly, severely reducing the cell cycle to just four days.
Psoriasis affects about 2% of all people in the westernized world and is more common in Caucasians than in other races. Although the disease can begin at any time in life, there are two peaks: from 20 to 30 years and from 50 to 60 years of age. However, in most people onset occurs before the age of 40. Men and women are equally affected by the disease, but women usually develop it earlier in their lives. Psoriasis also occurs earlier in patients with a family history of the disease.
Types of Psoriasis
Plaque psoriasis, also called psoriasis vulgaris, is the most common type of psoriasis, accounting for about 80% of all cases. It is characterized by raised, inflamed, red lesions covered with a silvery-white build-up of dead skin cells. This type of psoriasis may also affect the nails.
Psoriatic arthritis, also called psoriatic arthropathy or psoriasis arthropica, is associated with arthritis and it is generally similar to rheumatoid arthritis. Although psoriatic arthritis is typically milder than rheumatoid arthritis, it may also be disabling. This form frequently affects the fingers and toes.
Inverse psoriasis, also known as skin fold psoriasis, flexural or genital psoriasis, is marked by smooth, dry, red lesions that form in the folds of skin, commonly in the genital area, under the breasts and in the arm pits. This form most often occurs in overweight patients.
Guttate psoriasis is characterized by small, distinct, generally widespread red lesions. It most commonly begins in childhood, especially after respiratory infections.
Pustular psoriasis accounts for less than 5% of all cases of psoriasis. In this form, small, sterile pustules appear, dry up and form a scab. The blisters associated with pustular psoriasis are white, surrounded by red skin and are typically localized to palms and soles. This type of psoriasis can be very severe and may be associated with systemic symptoms including diarrhea, fever and unwell feeling. Pustsular psoriasis is rapidly worsened by overindulgence of alcohol and overuse of oral steroids.
Erythrodermic psoriasis, also known as psoriasis universalis, is the least common but particularly severe type of psoriasis. It is marked by intense redness that covers all or most of the body surface. Erythrodermic psoriasis often causes very high fever and a greatly increased susceptibility to infection, generally requiring hospitalization.
Causes and Risk Factors for Psoriasis
It is believed that a faulty response of the immune system is responsible for the rapid turnover of cells in the epidermis which causes the skin changes so typical of psoriasis. Genetics is another factor involved in the development of this condition as there is a family history of psoriasis in about one-third of all psoriasis patients. The onset of psoriasis as well as further flares and exacerbations are thought to require a trigger. The most common triggers include:
- Skin injury, including cuts, bruises, bites, chafing, burns or sunburns
- Viral or bacterial infection
- Emotional stress
- Certain drugs, such as beta blockers, lithium, antimalarial drugs and the prolonged use of oral steroids
- Hormonal factors, including hypocalcemia and those involved in pregnancy
- Climatic conditions, including lack of sunlight and dry weather
- Alcohol abuse and heavy smoking
Symptoms of Psoriasis
The most characteristic symptom of psoriasis is the lessons which may differ largely from person to person. At first they usually appear as very small, dot-like, red spots and then gradually enlarge. The affected skin thickens and becomes dry, cracked and encrusted, forming raised patches. These patches are often swollen, red and itchy. When psoriasis is expanding, the itching may become more severe. Lesions are typically covered with flaky, silvery, yellow-white scales. Psoriasis lesions in children are generally not as thick and may be less scaly. Although lesions vary in size and shape, their borders are always distinct. There is often only one or a few patches, but they may also cover large areas of skin and merge into each other.
The scales on the surface come off easily and are constantly shed. The skin beneath the scale layer is typically very red and may be tender and painful. However, in dark-skinned individuals, this skin may be almost the same color as the rest of the skin instead of a bright red color. Also, the lesions are sometimes surrounded by a ring of pale skin.
Lesions may occur anywhere on the body and, in many cases, they appear symmetrically on both sides of the body. They commonly occur at sites of skin injury and on the scalp, elbows, knees, naval area, buttocks, lower back and genitalia. They may also appear on the palms, fingernails, soles, toenails or even inside the mouth. Children also develop facial lesions. Psoriasis may affect body movement and flexibility and can even be disabling when lesions appear in areas such as palms or soles. The itchiness associated with severe cases of psoriasis can disrupt a person’s sleep.
Other symptoms of psoriasis may include:
- Affected nails frequently become pitted. A yellow-brown staining and lifting of the nail from the nail bed as well as thickening and ridging of the nail may also occur.
- The eyes may itch, burn or have discharge. Inflammation of the eyelids or inner eye lining may also occur.
- Unaffected skin may sometimes become thin and easily torn.
- When psoriasis is associated with arthritis (psoriatic arthritis), joint involvement typically occurs after skin lesions are already apparent.
In very mild cases of psoriasis, a person may often be completely unaware of the disease. However, most cases of psoriasis do trigger some of the aforementioned symptoms.
In most cases, psoriasis is diagnosed through observation of the lesions in the doctor’s office. When psoriatic arthritis is suspected, x-rays and blood tests may be ordered to look for early signs of arthritis. If a diagnosis is not definite, it can be confirmed with a skin biopsy. Psoriasis may be sometimes difficult to diagnose because some other conditions can be confused for it. These may include:
- Seborrheic dermatitis is the most common condition to be confused with psoriasis.
- Eczema is a skin condition with itchy and inflamed lesions, including atopic dermatitis and allergic contact dermatitis.
- Parapsoriasis is a form of generally painless, scaly dermatitis.
- Sézary syndrome is a form of itchy, shedding dermatitis.
- Pityriasis rubra pilaris is marked by a scaly eruption of the hair follicles.
- Pityriasis rosea causes dry, scaly eruptions that disappear spontaneously and rarely recur.
- Impetigo is a bacterial skin infection characterized by crusty lesions.
- Superficial candidiasis is a yeast infection of the skin.
- Secondary syphilis which is characterized by skin rash.
Treatment of Psoriasis
Though there is no ultimate cure for psoriasis, available treatments may temporarily clear lesions and/or substantially improve the appearance of the skin. The aim of treatment is to eliminate lesions by reducing inflammation and slowing down the rapid cell proliferation and shedding. Treatment must be individualized and may require periodic adjustment. Once treatment has cleared present lesions, it is usually discontinued until new lesions emerge. Most patients require lifelong therapy to control the symptoms associated with psoriasis.
Any treatment for psoriasis generally focuses on certain factors, such as softening and removing scales, slowing rapid cell growth, reducing itching, pain and discomfort and helping to induce remission. The factors like location and size of lesions on the body, type and severity of the condition, patient’s age, overall health, medical history, tolerance of specific medications or therapies determine the course of treatment that will be proposed.
Topical medications can be used either alone, or in combination, or with exposure to ultraviolet light to treat mild to moderate psoriasis. Any existing scales need to be removed before application of topical agents because they block their penetration. This can be achieved through hydration (e.g., soaking in a warm bath), or with medications that soften the skin (e.g., commonly used salicylic acid). Topical medications for psoriasis include:
- Moisturizers (emollients) restore moisture and flexibility to affected skin and may reduce inflammation, itching and scaling. They can be particularly beneficial in dry climates or during winter. Mild, non-perfumed moisturizers can be purchased without a prescription.
- Coal tar preparations may be added in bath water, applied directly to the lesion, or used in combination with UVB light. Coal tar preparations are available with or without a prescription. A coal tar shampoo may be used for scalp psoriasis.
- Corticosteroids happen to be the most commonly prescribed medications for psoriasis. Though quite helpful in mild to moderate psoriasis, corticosteroids are not usually effective in severe psoriasis. Their prolonged use is even known to result in rebound psoriasis worse than the original condition.
- Calcipotriene in the form of an ointment is used to slow skin cell proliferation. It is particularly effective when used in combination with topical corticosteroid treatment such as the steroid betamethasone dipropionate. Additional benefits include flattening of the lesions and removing scales.
- Retinoids, such as tazarotene, are a synthetic form of vitamin A. They work by slowing the skin cell renewal. Topical retinoids are prescription medications that may cause skin irritation and increase susceptibility to sunburn.
- Anthralin may be applied to thicker, harder-to-treat lesions in order to reduce increase in skin cells and inflammation.
- Bath solutions, such as Epsom salts, Dead Sea salts or oilated oatmeal added to baths, may bring some relief from itching.
Occlusion can be used with topical medications to improve their absorption. Lesions are covered with tape dressing, plastic wrap, cellophane or a special suit.
Phototherapy is frequently used in the treatment of moderate to severe psoriasis. Natural sunlight or ultraviolet light exposure may help reduce lesions. However, patients must be careful to avoid burns, because sunburn can make psoriasis yet worse. Methods of delivering ultraviolet light include:
- Psoralen and long-wave ultraviolet radiation (PUVA). Psoralen is a light-sensitizing medication applied topically or orally before exposure to ultraviolet A light. PUVA therapy is not suitable for children under the age of 12, pregnant or breastfeeding women and individuals with medical conditions such as liver or kidney dysfunction. Possible side effects include redness of the skin, nausea, vomiting, itching, abnormal hair growth and hyperpigmentation.
- Narrow-band UVB (NB-UVB). Intense ultraviolet B light may also reduce lesions. Narrow-band UVB clears psoriasis faster than PUVA and, unlike PUVA, it can be used in children, pregnant or breastfeeding women and patients with liver or kidney dysfunction. It is also believed to be superior to broad-band UVB.
- Laser treatments, such as an excimer laser and pulsed dye laser, may be used to treat mild to moderate cases of chronic, localized psoriasis with high-intensity beam of UVB light which targets specific areas of the affected skin.
Oral medications, such as soriatane, cyclosporine, methotrexate, apremilast and sulfasalazine, may be used to treat severe cases of psoriasis that do not respond well to other forms of treatment. Some of these medications may also be given by injection. However, they are usually less-well tolerated than topical treatments, so the benefits of their use must be weighed against their possible side effects. Some oral medications can cause serious complications. For example, patients treated with methotrexate, an antimetabolite that interrupts the growth of skin cells, must be monitored for kidney, liver and blood changes. The new oral treatment called apremilast regulates inflammation within the cell by correcting the overactive immune response that causes it. It is less likely to cause serious side effects than older oral treatments.
Biologics are amongst the latest treatments for psoriasis. They are administered intravenously or via intramuscular injection. Biologics treat moderate to severe psoriasis and psoriatic arthritis by working on specific parts of the immune system which are involved in triggering psoriasis.
Psoriasis cannot be prevented. However, patients with psoriasis can help prevent further flares by identifying and avoiding triggers that cause or worsen their condition. The triggers may be different for every patient and may include skin injuries, infections, heavy smoking, drinking too much alcohol, emotional stress, lack of sleep and drying the skin too much by long showers in hot water.
Where to Get More Information: National Psoriasis Foundation