Psoriasis
| Psoriasis | |
|---|---|
| Specialty | Dermatology  |
Psoriasis is an immune-mediated disease which affects the skin and joints. When it affects the skin it commonly appears as red scaly elevated patches called plaques. Psoriasis plaques frequently occur on the elbows and knees, but can affect any area of skin including the scalp and genital area. Psoriasis can vary in severity, from minor localised patches to complete skin coverage. Fingernails and toenails are often affected (psoriatic nail dystrophy). Psoriasis can also cause inflammation of the joints. This is known as psoriatic arthritis. Psoriatic arthritis can affect any joint but is most common in the joints of the fingers and toes. This can result in a sausage-shaped swelling of the fingers and toes known as dactylitis. Psoriatic arthritis can also affect the hips, knees and spine (spondylitis).
The prevalence of psoriasis in Western populations is estimated to be around 2-3%. It affects both sexes equally and occurs at all ages.
Several factors are thought to aggravate psoriasis. These include stress and excessive alcohol consumption. Individuals with psoriasis may also suffer from depression and loss of self-esteem. As such, quality of life is an important factor in evaluating the severity of the disease. There are many treatments available but because of its chronic recurrent nature psoriasis is a challenge to treat.
Types of psoriasis
Psoriasis can appear in several forms. Variants include plaque, pustular, guttate and flexural psoriasis. This section describes each type and provides its ICD-10 code. [1]
Plaque psoriasis (psoriasis vulgaris) (L40.0)
Plaque psoriasis is the most common form of psoriasis. It affects 80 to 90% of people with psoriasis. Plaque psoriasis typically appears as raised areas of inflamed skin covered with silvery white scaly skin. These areas are called plaques.
Flexural psoriasis (inverse psoriasis) (L40.83-4)
Flexural psoriasis appears as smooth inflamed patches of skin. It occurs in skin folds, particularly around the genitals, the armpits, and under the breasts. It is aggravated by friction and sweat, and is vulnerable to fungal infections.
Guttate psoriasis (L40.4)
Guttate psoriasis is characterized by numerous small oval (teardrop-shaped) spots. These numerous spots of psoriasis appear over large areas of the body, such as the trunk, limbs, and scalp. Guttate psoriasis frequently occurs after a streptococcal throat infection.
Pustular psoriasis (L40.1-3, L40.82)
Pustular psoriasis appears as raised bumps that are filled with non-infectious pus (pustules). The skin under and surrounding pustules is red and tender. Pustular psoriasis can be localised, commonly to the hands and feet (palmoplantar pustulosis), or generalised with widespread patches occurring randomly on any part of the body. The occurrence of pustular psoriasis has been associated with infection, and the use or withdrawal of certain medications.
Nail psoriasis (L40.86)
Psoriasis affecting the nails produces a variety of changes in the appearance of finger and toe nails. These changes include discolouring under the nail plate, pitting of the nails, lines going across the nails, thickening of the skin under the nail, and the loosening (onycholysis) and crumbling of the nail.
Psoriatic arthritis (L40.5)
Psoriatic arthritis involves joint and connective tissue inflammation. Psoriatic arthritis can affect any joint but is most common in the joints of the fingers and toes. This can result in a sausage-shaped swelling of the fingers and toes known as dactylitis. Psoriatic arthritis can also affect the hips, knees and spine (spondylitis). About 10-20% of people who have skin psoriasis also have psoriatic arthritis.
Erythrodermic psoriasis (L40.85)
Erythrodermic psoriasis involves the widespread inflammation and exfoliation of the skin over most of the body surface. It may be accompanied by severe itching, swelling and pain. It is often the result of an exacerbation of unstable plaque psoriasis, particularly following the abrupt withdrawal of systemic treatment. This form of psoriasis can be fatal, as the extreme inflammation and exfoliation disrupt the body's ability to regulate temperature and for the skin to perform barrier functions.
Effect on the quality of life
Depending on the severity and location of outbreaks, individuals may experience significant physical discomfort and some disability. Itching and pain can interfere with basic functions, such as self-care, walking, and sleep. Plaques on hands and feet can prevent individuals from working at certain occupations, playing some sports, and caring for family members or a home. The frequency of medical care is costly and can interfere with an employment or school schedule.
Individuals with psoriasis may also feel self-conscious about their appearance and have a poor self-image that stems from fear of public rejection and psychosexual concerns. Psychological distress can lead to significant depression and social isolation.
Cause
The cause of psoriasis is not fully understood. There are two main theories about the process that occurs in the development of the disease. The first, considers psoriasis as primarily a disorder of excessive growth and reproduction of skin cells. The problem is simply seen as a fault of the epidermis and its keratinocytes. An alternate viewpoint sees the disease as being an immune-mediated disorder in which the excessive reproduction of skin cells is secondary to factors produced by the immune system. It is thought that T cells (which normally help protect the body against infection) become active, migrate to the dermis and trigger further immune responses which cause inflammation and the rapid turnover of skin cells. It is not known what initiates the activation of the T cells.
The immune-mediated model of psoriasis has been supported by the observation that immunosuppressant medications can clear psoriasis plaques. However, the role of the immune system is not fully understood, and it has recently been reported that an animal model of psoriasis can be triggered in mice lacking an immune system (Zenz et al, 2005).
Around one-third of people with psoriasis report a family history of the disease, and researchers have identified several genetic loci associated with the condition. Studies of monozygotic twins suggest a 70% chance of a twin developing psoriasis if the other twin has psoriasis. The concordance is around 20% for dizygotic twins. These finding suggests both a genetic predisposition and an enviromental response in developing psoriasis.
Psoriasis is a fairly idiosyncratic disease. The majority of people's experience of psoriasis is one in which it may worsen or improve for no apparent reason. Studies of the factors associated with psoriasis tend to be based on small (usually hospital based) samples of individuals. These studies tend to suffer from representative issues, and an inability to tease out causal associations in the face of other (possibily unknown) intervening factors. Conflicting findings are often reported. Nevertheless, the first outbreak is sometimes reported following stress (emotional and mental), skin injury, and streptococcal infection. Conditions that have been reported as accompanying a worsening of the disease include infections, stress, changes in season and climate. Certain medicines, including lithium salt and beta blockers have been reported to trigger or aggravate the disease. Excessive alcohol consumption, smoking and obesity may exacerbate psoriasis or make the management of the condition difficult.
Treatment
Dermatologists are the medical specialists with expertise in psoriatic treatment. Treatment decisions are based on the type of psoriasis, its location, extent and severity. The patient’s age, gender, quality of life, and attitude toward the risk are also considered.
In general treatment progresses in a stepwise manner. This is sometimes called the "1-2-3" approach. In step 1, medicines are applied to the skin (topical treatment). Step 2 uses ultraviolet light treatments (phototherapy). Step 3 involves taking medicines by mouth or injection (called systemic therapy).
Over time, affected skin can become resistant to treatment, especially when topical corticosteroids are used. Also, a treatment that works well in one person may have little effect in another. Thus, doctors often use a trial-and-error approach to find a treatment that works, and they may switch treatments periodically (for example, every 12 to 24 months) if a treatment does not work or if adverse reactions occur.
Topical treatment
Treatments applied directly to the skin may improve its condition. Some people with psoriasis respond well to ointment or cream forms of corticosteroids, vitamin D3, retinoids, coal tar, or anthralin. Bath solutions and moisturizers may be soothing, but they are seldom strong enough to improve the condition of the skin. However they help with the penetration of additonal stronger remedies and so maximise the effectiveness of combination therapy. In additon steroids and calcipotriol may cause an initial burning sensation if applied to dry skin.
Moisturizers
When applied regularly over a long period, moisturizers have a soothing effect. Preparations that are thick and greasy (ointments) usually work best because they seal water in the skin, reducing scaling and itching.
Bath solutions
People with psoriasis may find that adding oil when bathing, then applying a moisturizer, soothes their skin. Also, individuals can remove scales and reduce itching by soaking for 15 minutes in water containing a coal tar solution, oiled oatmeal, Epsom salts, or Dead Sea salts.
Salicylic acid
Salicylic acid, a peeling agent, can be applied to reduce scaling of the skin or scalp; it is available in many forms, such as ointments, creams, gels, and shampoos. Often, it is more effective when combined with topical corticosteroids, anthralin, or coal tar.
Coal tar
Preparations containing coal tar (gels and ointments) may be applied directly to the skin, added (as a liquid) to the bath, or used on the scalp as a shampoo. Coal tar products are available in different strengths, and many are sold over the counter (not requiring a prescription). It is less effective than corticosteroids and many other treatments and, therefore, is sometimes combined with ultraviolet B (UVB) phototherapy for a better result. Coal tar has an effect on some of the enzymes involved in psoriasis, and it increases the skin's sensitivity to light. The most potent form may irritate the skin, is messy, has a strong odor, and may stain the skin or clothing. Thus, it is not popular with many patients.
Corticosteroids
These drugs reduce inflammation and the turnover of skin cells, and they suppress the immune system. Available in different strengths, topical corticosteroids (e.g., hydrocortisone) are usually applied to the skin twice a day. Short-term treatment is often effective in improving, but not completely eliminating, psoriasis. Long-term use or overuse of highly potent (strong) corticosteroids can cause thinning of the skin, internal side effects, and resistance to the treatment's benefits. If less than 10 percent of the skin is involved, some doctors will prescribe a high-potency corticosteroid ointment (e.g. Clobetasol propionate). High-potency corticosteroids may also be prescribed for plaques that don't improve with other treatment, particularly those on the hands or feet. In situations where the objective of treatment is comfort, medium-potency corticosteroids may be prescribed for the broader skin areas of the torso or limbs. Low-potency preparations are used on delicate skin areas. Cortisol (a.k.a. hydrocortisone) is an inexpensive corticosteroid available over the counter (without a prescription) in strengths that may be effective on very mild and emerging plaques. (Note: Brand names for the different strengths of corticosteroids are too numerous to list.)
Other side effects of corticosteroids are stretch marks in the skin, and rosacea that can affect the facial skin.
When using corticosteroids, it is important to follow the doctor's advice. Corticosteroids are very useful in the treatment of psoriasis, and used the correct way, side effects are seldom a problem. It is possible, however, for the condition to be aggravated on ceasing steroidal treatment, particulary after overuse (rebound effect). It is therefore essential that they are used in the correct way and instructions carefully followed.
Calcipotriol
Calcipotriol (Calcipotriene (USAN)) is a synthetic form of vitamin D3 that can be applied to the skin. Applying calcipotriol (for example, Daivonex®/Dovonex®) once to twice a day controls the speed of turnover of skin cells. It is sometimes combined with topical corticosteroids to reduce irritation. It is available as cream, ointment and scalp solution. As well as causing skin irritation, especially if applied to dry un-moisturised skin, it may worsen the psoriasis and cause the onset of facial psoriasis amongst other side-effects. It should not be used on folds of skin, and should never be used on the face. Some countries require blood testing before and during use to monitor any changes in the levels of calcium in the blood. Hands should be washed thoroughly after use.
Combined calcipotriol and corticosteroid
Calcipotriol is usually not to be mixed with corticosteroids at the same time due to problems with the active substances interfering with each other. Lately a product has appeared that combines Betamethasone dipropionate, a steroid based product and calcipotriol (Daivobet®/Dovobet®). This product is characterized by its rapid onset of action. The product is also more effective than the two products used separately. A third advantage with this product over most other products used to treat psoriasis is that its applied only once daily. Daivobet/Dovobet is documented to be a safe treatment for up to a years duration.[citation needed]
Retinoids
Topical retinoids are synthetic forms of vitamin A. The retinoid tazarotene (Tazorac) is available as a gel or cream that is applied to the skin. If used alone, this preparation does not act as quickly as topical corticosteroids, but it does not cause thinning of the skin or other side effects associated with steroids. However, it can irritate the skin, particularly in skin folds and the normal skin surrounding a patch of psoriasis. It is less irritating and sometimes more effective when combined with a corticosteroid. Because of the risk of birth defects, women of childbearing age must take measures to prevent pregnancy when using tazarotene.
Anthralin
Anthralin reduces the increase in skin cells and inflammation. Doctors sometimes prescribe a 15- to 30-minute application of anthralin ointment, cream, or paste once each day to treat chronic psoriasis lesions. Afterward, anthralin must be washed off the skin to prevent irritation. This treatment often fails to adequately improve the skin, and it stains skin, bathtub, sink, and clothing brown or purple. In addition, the risk of skin irritation makes anthralin unsuitable for acute or actively inflamed eruptions.
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 broadband 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.
A newer type of UVB, called narrowband UVB, emits the part of the ultraviolet light spectrum band that is most helpful for psoriasis. Narrowband UVB treatment is superior to broadband UVB, but it may be 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 narrowband 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, narrowband UVB treatment is not without risk. It can cause more severe and longer lasting burns than broadband 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 broadband 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 short term 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 ciclosporin, have little beneficial effect and increase the risk of cancer...
Computerized tunable targeted light systems
Newly developed tunable targeted multiwavelength system claim to supersede classical phototherapy. These systems use narrow band UVB targeted selectively to the psoriatic lesions through a fiber optic delivery system. Since by using these systems light targets only the psoriatic lesions there is no damage to surrounding normal skin. Since normal skin is not exposed, high intensity may be used allowing clearing of psoriatic plaques in 8-10 treatments instead of 30 to 40 treatments with the classical full body phototherapy units.
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.
X-ray radiation
Stubborn psoriasis on the scalp can be treated with a form of X-ray radiation called Grenz ray. There is a limit to the number of treatments that can be given. Effect is said to be longer lasting than other treatments. This form of therapy is considered to have unacceptable risks and is no longer used in most countries.
Systemic treatment
For more severe forms of psoriasis, doctors sometimes prescribe medicines that are taken internally by pill or injection. This is called systemic treatment. Systemic therapy should be instituted under the careful guidance of a specialist dermatologist.
Methotrexate
Like ciclosporin, methotrexate slows cell turnover by suppressing the immune system. It can be taken by pill or injection. Patients taking methotrexate must be closely monitored because it can cause liver damage and/or decrease the production of oxygen-carrying red blood cells, infection-fighting white blood cells, and clot-enhancing platelets. As a precaution, doctors do not prescribe the drug for people who have had liver disease or anemia (an illness characterized by weakness or tiredness due to a reduction in the number or volume of red blood cells that carry oxygen to the tissues). It is sometimes combined with PUVA or UVB treatments. Methotrexate should not be used by pregnant women, or by women who are planning to get pregnant, because it may cause birth defects.
Retinoids
A retinoid, such as acitretin (Soriatane or Neotigason), is a compound with vitamin A-like properties that may be prescribed for severe cases of psoriasis that do not respond to other therapies. Because this treatment may also cause birth defects, women must protect themselves from pregnancy beginning 1 month before through 3 years after treatment with acitretin. Most patients experience a recurrence of psoriasis after these products are discontinued. Common side effects include dry lips, hands and feet. Use of retinoids in conjunction with UV treatments has been found to be very effective for some people.
Ciclosporin
Taken orally, ciclosporin (also spelled as cyclosporin(e)) works by suppressing the immune system to slow the rapid turnover of skin cells. It may provide quick relief of symptoms, but the improvement stops when treatment is discontinued. The best candidates for this therapy are those with severe psoriasis who have not responded to, or cannot tolerate, other systemic therapies. Its rapid onset of action is helpful in avoiding hospitalisation of patients whose psoriasis is rapidly progressing. Ciclosporin may impair kidney function or cause high blood pressure (hypertension). Therefore, patients must be carefully monitored by a doctor. Also, ciclosporin is not recommended for patients who have a weak immune system or those who have had skin cancers as a result of PUVA treatments in the past. It should not be given with phototherapy.
This drug is nearly as effective as methotrexate and ciclosporin. It has fewer side effects, but there is a greater likelihood of anemia. This drug must also be avoided by pregnant women and by women who are planning to become pregnant, because it may cause birth defects.
Compared with methotrexate and ciclosporin, hydroxyurea is somewhat more effective. It is sometimes combined with PUVA or UVB treatments. Possible side effects include anemia and a decrease in white blood cells and platelets. Like methotrexate and retinoids, hydroxyurea must be avoided by pregnant women or those who are planning to become pregnant, because it may cause birth defects. This is an extremely potent drug that was originally used to treat cancer patients in combination with chemotherapy.
These medications are not indicated in routine treatment of psoriasis. However, antibiotics may be employed when an infection, such as that caused by the bacteria Streptococcus, triggers an outbreak of psoriasis, as in certain cases of guttate psoriasis.
One of the newest classes of treatment for psoriasis are drugs collectively known as "biologics". These in general are types of manufactured proteins that attempt to impact the actual immune pathway of psoriasis, instead of affected skin cells. However, unlike other immunosuppression therapies such as Methotrexate, biologics try to narrowly focus on the one aspect of the immune function causing the psoriasis instead of broad immune system suppression. These drugs have only recently begun to receive approval by the FDA, and their long-term impact on immune function is currently unknown. Examples of biologics would be compounds such as Amevive®, etanercept (Enbrel®), Humira®, infliximab (Remicade®) and Raptiva.
Unproven anecdotal evidence suggests that psoriasis can be effectively managed through a healthy lifestyle. Some sufferers have found that minimizing stress and consumption of alcohol, sugar and other "aggressive" foods, combined with rest, sunshine and swimming in saltwater keep lesions to a minimum. This type of "lifestyle" treatment is effective as a long-term management strategy, rather than initial treatment of severe cases. One sufferer describes his psoriasis as his "barometer" which lets him know when he is getting too stressed and not living "well." This positive attitude and proactive approach can be an effective part of, or short-term replacement for, medical solutions.
Some also cite anecdotal evidence that vegetarianism prevents outbreaks of psoriasis.
Prognosis
Psoriasis is a chronic, meaning lifelong, condition because there is currently no cure. People often experience flares and remissions throughout their life. Controlling the signs and symptoms typically requires lifelong therapy.
References
Some of the information on this page was taken from the public-domain resource at:
For an in-depth coverage of the causes of psoriasis:
- Gudjonsson JE, Johnston A, Sigmundsdottir H, Valdimarsson H.; (2004). "Immunopathogenic mechanisms in psoriasis". Clin Exp Immunol. 135 (1): 1–8. PMID 14678257.
{{cite journal}}: CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link)
For a recent review of innate immunity aggravation in psoriasis:
- Bos J, de Rie M, Teunissen M, Piskin G (2005). "Psoriasis: dysregulation of innate immunity". Br J Dermatol. 152 (6): 1098–107. PMID 15948970.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Zenz R, Eferl R, Kenner L, Florin L, Hummerich L, Mehic D, Scheuch H, Angel P, Tschachler E, Wagner E (2005). "Psoriasis-like skin disease and arthritis caused by inducible epidermal deletion of Jun proteins". Nature. 437 (7057): 369–75. PMID 16163348.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Krueger G, Ellis C (2005). "Psoriasis--recent advances in understanding its pathogenesis and treatment". J Am Acad Dermatol. 53 (1 Suppl 1): S94-100. PMID 15968269.