牛皮癬
维基百科，自由的百科全书
| Psoriasis 分類系統及外部資源 |
|
 |
|
|---|---|
| A young man whose back and arms are affected by psoriasis. | |
| ICD-10 | L40. |
| ICD-9 | 696 |
| OMIM | 177900 |
| DiseasesDB | 10895 |
| MedlinePlus | 000434 |
| eMedicine | emerg/489 Dermatology:derm/365 plaque derm/361 guttate derm/363 nails derm/366 pustular Arthritis derm/918 Radiology radio/578 Physical Medicine pmr/120 |
| MeSH | D011565 |
牛皮癬（Psoriasis），又名“白疕”，正式名稱是銀屑病，是一種「自體免疫系統失調」，現時已變得愈來愈普遍，特別是已發展的城市。牛皮癬並不是一種傳染病，但因為牛皮癬患者的皮膚問題，使他們在尋找工作時出現困難，特別是情況嚴重的患者。
牛皮癬的成因，現時仍然未明白，古希臘人認為牛皮癬是眾神的詛咒，並強迫牛皮癬患者搖鈴，以防被傳染。曾國藩患有嚴重的牛皮癬，每晚要婢女為他搔癢方能入睡，終身未能痊癒。過去由於以主婦及餐飲業工作者較多，曾一度認為是他們用來洗手的清潔劑有關。由於當時社會認為牛皮癬會傳染，為免客人錯誤進食含有皮屑的食物而被傳染，這些員工都會被餐廳解僱。現時普遍認為是因為生活壓力過大，以致病者的「內分泌失調」，從而影響身體的免疫系統。所以，醫生有時會為病者處方「維生素B雜」，以幫助紓緩壓力；亦有醫生認為病者應該多做帶氧運動，使身體的自然調節機制透過運動而自我調整。在香港，有很多學生和教師都有局部的牛皮癬，主要集中在手掌、手臂、雙腿或肩膀。在美國，最近有藥廠發明了一種針劑，可以對嚴重患者的病程控制，使他們的皮膚回復光滑。這種針劑在2006年亦被引入到加拿大進行臨床測試。不過，這種針劑不能根治銀屑病，一旦停止注射，問題會立即重現。
目录 |
[编辑] 治疗
不同的治疗方法的效果因人而异. 皮肤科医生通常要通过反复试验来决定拿一种疗法最适合病人. 疗法的选择取决于牛皮癬的类别, 部位, 以及范围和严重程度. 同时也要兼顾病人的年龄, 性别, 生活质量, 共病, 以及对治疗所导致的危险的承受能力.
Medications with the least potential for adverse reactions are preferentially employed. If the treatment goal is not achieved then therapies with greater potential toxicity may be used. Medications with significant toxicity are reserved for severe unresponsive psoriasis. This is called the psoriasis treatment ladder.[1] As a first step, medicated ointments or creams, called topical treatments, are applied to the skin. If topical treatment fails to achieve the desired goal then the next step would be to expose the skin to ultraviolet (UV) radiation. This type of treatment is called phototherapy. The third step involves the use of medications which are taken internally by pill or injection. This approach is called systemic treatment.
Over time, psoriasis can become resistant to a specific therapy. Treatments may be periodically changed to prevent resistance developing (tachyphylaxis) and to reduce the chance of adverse reactions occurring. This is called treatment rotation.
[编辑] 外服疗法
Bath solutions and moisturizers help soothe affected skin and reduce the dryness which accompanies the build-up of skin on psoriatic plaques. Medicated creams and ointments applied directly to psoriatic plaques can help reduce inflammation, remove built-up scale, reduce skin turn over, and clear affected skin of plaques. Ointment and creams containing coal tar, dithranol (anthralin), corticosteroids like desoximetasone (Topicort), vitamin D3 analogues (for example, calcipotriol), and retinoids are routinely used. Argan oil has also been used with some promising results.[2] The mechanism of action of each is probably different but they all help to normalise skin cell production and reduce inflammation. Activated vitamin D and its analogues are highly effective inhibitors of skin cell proliferation.
The disadvantages of topical agents are variably that they can often irritate normal skin, can be time consuming and awkward to apply, cannot be used for long periods, can stain clothing or have a strong odour. As a result, it is sometimes difficult for people to maintain the regular application of these medications. Abrupt withdrawal of some topical agents, particularly corticosteroids, can cause an aggressive recurrence of the condition. This is known as a rebound of the condition.
Some topical agents are used in conjunction with other therapies, especially photo therapy.
[编辑] 光疗
It has long been recognized that daily, short, non-burning exposure to sunlight helped to clear or improve psoriasis. Niels Finsen was the first physician to investigate the therapeutic effects of sunlight scientifically and to use sunlight in clinical practice. This became known as phototherapy.
Sunlight contains many different wavelengths of light. It was during the early part of the 20th century that it was recognised that for psoriasis the therapeutic property of sunlight was due to the wavelengths classified as ultraviolet (UV) light.
Ultraviolet wavelengths are subdivided into UVA (380–315 nm) UVB (315–280 nm), and UVC (< 280 nm). Ultraviolet B (UVB) (315–280 nm) is absorbed by the epidermis and has a beneficial effect on psoriasis. Narrowband UVB (311 to 312 nm), is that part of the UVB spectrum that is most helpful for psoriasis. Exposure to UVB several times per week, over several weeks can help people attain a remission from psoriasis.
Ultraviolet light treatment is frequently combined with topical (coal tar, calcipotriol) or systemic treatment (retinoids) as there is a synergy in their combination. The Ingram regime, involves UVB and the application of anthralin paste. The Goeckerman regime combines coal tar ointment with UVB.
[编辑] 光化学疗法
Psoralen and ultraviolet A phototherapy (PUVA) combines the oral or topical administration of psoralen with exposure to ultraviolet A (UVA) light. Precisely how PUVA works is not known. The mechanism of action probably involves activation of psoralen by UVA light which inhibits the abnormally rapid production of the cells in psoriatic skin. There are multiple mechanisms of action associated with PUVA, including effects on the skin immune system.
PUVA is associated with nausea, headache, fatigue, burning, and itching. Long-term treatment is associated with squamous-cell and melanoma skin cancers.
[编辑] 内服疗法
Psoriasis which is resistant to topical treatment and phototherapy is treated by medications that are taken internally by pill or injection. This is called systemic treatment. Patients undergoing systemic treatment are required to have regular blood and liver function tests because of the toxicity of the medication. Pregnancy must be avoided for the majority of these treatments. Most people experience a recurrence of psoriasis after systemic treatment is discontinued.
The three main traditional systemic treatments are methotrexate, cyclosporine and retinoids. Methotrexate and cyclosporine are immunosupressant drugs; retinoids are synthetic forms of vitamin A. Other additional drugs, not specifically licensed for psoriasis, have been found to be effective. These include the antimetabolite tioguanine, the cytotoxic agent hydroxyurea, sulfasalazine, the immunosupressants mycophenolate mofetil, azathioprine and oral tacrolimus. These have all been used effectively to treat psoriasis when other treatments have failed. Although not licensed in many other countries fumaric acid esters have also been used to treat severe psoriasis in Germany for over 20 years.
Biologics are manufactured proteins that interrupt the immune process involved in psoriasis. Unlike generalised immunosuppressant therapies such as methotrexate, biologics focus on specific aspects of the immune function leading to psoriasis. These drugs (interleukin antagonists) are relatively new, and their long-term impact on immune function is unknown. They are very expensive and only suitable for very few patients with psoriasis. Ustekinumab (IL-12 and IL-23 blocker) shows hopeful results for psoriasis therapy.
[编辑] 替代疗法
Milk thistle is believed to help prevent psoriasis outbreaks by encouraging proper liver function. The liver neutralizes certain toxins associated with psoriasis.[3]
Antibiotics 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.
Climatotherapy involves the notion that some diseases can be successfully treated by living in a particular climate. Several psoriasis clinics are located throughout the world based on this idea. The Dead Sea is one of the most popular locations for this type of treatment.
In Turkey & in Croatia (Altermedica), doctor fish which live in the outdoor pools of spas, are encouraged to feed on the psoriatic skin of people with psoriasis. The fish only consume the affected areas of the skin. The outdoor location of the spa may also have a beneficial effect. This treatment can provide temporary relief of symptoms. A revisit to the spas every few months is often required. Best known is the spa “Kangal Thermal Springs”, near the Turkish village of Kavak. According to the testimony of numerous psoriasis patients, the fish lead to a significant relief. This spa is located south of the historic silk road in Anatolia. The next big city is Sivas. Treatment in this hot spring has been examined until now in two small clinical trials, with positive results.[4] [5]
Some peopleTemplate:Who subscribe to the view that psoriasis can be effectively managed through a healthy lifestyle. This view is based on anecdotal evidence, and has not been subjected to formal scientific evaluation. Nevertheless, some people report that minimizing stress and consuming a healthy diet, combined with rest, sunshine and swimming in saltwater keep lesions to a minimum. This type of "lifestyle" treatment is suggested as a long-term management strategy, rather than an initial treatment of severe psoriasis.
A number of patients have reported significant improvements from sun and sea water: unfortunately, salt alone does not have any effect. Sea water contains so many minerals and different life forms (thousands of species of bacteria alone[6]) that it will be hard to determine which of these is causing the observed effects. Interestingly, people in the tropics differentiate between "live" and "dead" sea water: "live" sea water is water that has never been covered.[7]
Some psoriasis patients use herbology as a holistic approach that aims to treat the underlying causes of psoriasis. Some alternative therapies consider Oil of Oregano to be a powerful herbal method of treatment.
A psychological symptom management programme has been reported as being a helpful adjunct to traditional therapies in the management of psoriasis.[8]
Zinc oxide (ZnO) is used for several skin afflictions and according to some patients also provides relief.
[编辑] 先前疗法
The history of psoriasis is littered with treatments of dubious effectiveness and high toxicity. These treatments received brief popularity at particular time periods or within certain geographical regions. The application of cat faeces to red lesions on the skin, for example, was one of the earliest topical treatments employed in ancient Egypt. Onions, sea salt and urine, goose oil and semen, wasp droppings in sycamore milk, and soup made from vipers have all been reported as being ancient treatments.
In the more recent past Fowler's solution, which contains a poisonous and carcinogenic arsenic compound, was used by dermatologists as a treatment for psoriasis during the 18th and 19th centuries. Grenz rays (also called ultrasoft X-rays or Bucky rays) was a popular treatment of psoriasis during the middle of the 20th century. This type of therapy was superseded by ultraviolet therapy.
Undecylenic acid was investigated and used for psoriasis some 40 years ago.(cir. 1950~)[9]
All these treatments have fallen out of favour.
Sulphur was fashionable as a treatment for psoriasis in the Victorian and Edwardian eras. It has recently re-gained some credibility as a safe alternative to steroids and coal tar.
[编辑] 未来疗法的发展
Historically, agents used to treat psoriasis were discovered by experimentation or by accident. In contrast, current novel therapeutic agents are designed from a better understanding of the immune processes involved in psoriasis and by the specific targeting of molecular mediators. Examples can be seen in the use of biologics which target T cells and TNF inhibitors.
It has been suggested that cannabis might treat psoriasis, due to the anti-inflammatory properties of its cannabinoids, and the regulatory effects of THC on the immune system.[10] The adverse effects of cannabis might be overcome by use of more specific cannabinoid receptor medications,[11] to inhibit keratinocyte proliferation.[12]
Future innovation should see the creation of additional drugs that refine the targeting of immune-mediators further.[13]
Research into antisense oligonucleotides carries the potential to provide novel therapeutic strategies for treating psoriasis.[14]
ABT-874 is a human anti-IL-12 monoclonal antibody being developed by Abbott Laboratories in conjunction with Cambridge Antibody Technology for the treatment of multiple autoimmune diseases including psoriasis. Phase II trials have been completed and showed promising results.[15] Abbott was planning to initiate Phase III trials in 2007.[16]
In 2004, Tas and Avci [17] demonstrated cyclopamine’s clinical potential for the treatment of psoriasis and basal cell carcinoma in two preliminary proof of concept studies. By treating 31 psoriatic lesions in 7 patients, these authors asserted that topical cyclopamine was more effective in the clinical and histological clearance of guttate and plaque psoriasis than the topical steroid clobetasol-17 propionate.Furthermore, they demonstrated that concurrent application of cylopamine and clobetasol-17 propionate accelerated regression and clearance of selected lesions greater than cyclopamine alone with clearance times as early as 48 hours.They assert that cyclopamine inhibits the abnormal proliferation of epithelial cells, induces terminal differentiation, and is associated with the decreased presence of inflammatory cells, including CD41 lymphocytes.
On August 27, 2006, scientists led by Jeung-Hoon Lee created in the laboratory synthetic lipids called pseudoceramides which are involved in skin cell growth and could be used in treating skin diseases such as atopic dermatitis, a form of eczema characterized by red, flaky and very itchy skin; psoriasis, and glucocorticoid-induced epidermal atrophy, in which the skin shrinks due to skin cell loss.[18]
