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Psoriasis

Psoriasis is a chronic and enduring skin disease, which is characteristic of rapid development of new cells leading to the buildup of dead cells over the surface of skin. It results in the formation of scales, that may cause swelling, itching, bleeding and pain. This skin disorder is also associated with inflammation of joints leading to psoriatic arthritis.

There are different types of psoriasis namely:

Plaque psoriasis, nail psoriasis, scalp psoriasis, inverse psoriasis, guttate psoriasis, erythrodermic psoriasis, pustular psoriasis and psoriatic arthritis.

Causes

The exact reason for the development of psoriasis is not clear. Psoriasis is more common in young adults. When a bacteria or foreign particle enters the body, the immune system mediates a response in which antibodies are developed by the defense mechanism, the white blood cells. But with psoriasis, specialized white blood cells known as T lymphocytes or T cells become overactive and attack healthy skin cells by mistake. The process of maturation from normal cells to dead cells takes about 30 days normally, but the overactive T cells make the process to end in just 3-6 days. This results in irregular growth and rapid accumulation of dead cells. Some common triggers are mentioned below.

  • Genetic inheritance: When a foreign element enters the body, message to the immune system is conveyed by human leukocyte antigen or HLA. It is thought that ineffective functioning of HLA leads to the improper signal sent to the immune system. A family history of psoriasis has been observed in more than 30 percent cases, where parents or grand parents of the patients are affected.
  • Streptococcal throat infections may contribute to the development of psoriasis. Advanced levels of HIV may also act as a trigger.
  • Skin injuries, particularly in knees and elbows may initiate psoriasis.
  • Drugs that start or aggravate the symptoms include antimalarial, hypertensive medications, lithium and progesterone.
  • Stress may also trigger psoriasis, because a disappointment or annoyance leads to adrenal hormones production which may lower the immunity.
  • Lack of sunlight: The psoriasis symptoms increase mostly during winter season due to insufficient exposure to sunlight.
  • Too much sunlight isn’t good either. Sunburns and other skin problems may occur.

Symptoms

The following signs and symptoms are commonly observed with psoriasis:

  • Red patchy skin covered by scales
  • Dry and cracked skin
  • Painful plaques
  • Burning sensation
  • Itching
  • Thick nails
  • Painful and swollen joints (psoriatic arthritis)
  • Bleeding, especially if joints are affected
  • Restricted movement due to joint stiffness
  • Genital lesions in men
  • Too much dandruff

Tests and Diagnosis

The diagnosis of psoriasis is clinical and patients are usually diagnosed by identifying the typical appearance of lesions on skin which will be visible on various locations of the body. The diagnosis is mostly simple and straightforward. There are few important signs that can easily be found in patients, which helps in confirming the diagnosis without the need of further investigations.

  • Physical examination: The dermatologist performs a serious visual inspection, examining the skin, nails and scalp. Recent injuries, illnesses and medications used may also be investigated during examination.
  • Koebner phenomenon: It is the occurrence of new psoriatic lesions at the site of skin injury. It develops each time the skin is injured.
  • Auspitz’s sign: It is the pinpoint skin bleeding that occurs when the characteristic scaly lesion is peeled off from the skin. It is one of the diagnostic signs and it is also common to few other skin conditions. It is not specific for psoriasis.
  • Skin biopsy: A skin biopsy is required when the diagnosis requires more detailed study to confirm the presence of psoriasis. In skin biopsy, a small sample of affected skin is examined under a microscope to confirm that the abnormalities are due to psoriasis and to find the exact type of psoriasis.
  • Woronoff ring: The surrounding normal skin around the plaque is usually pale which gives a ring like appearance. The investigation is usually done to diagnose the typical cases in skin biopsy.

Treatment

No current available treatment can guarantee a cure for psoriasis, but different treatment options offer relaxation in various signs and symptoms. The treatment offered varies from individual to individual, which depends on the severity of disease.

Phototherapy is used in treating moderate psoriasis, except for PUVA therapy which is reserved for severe form of psoriasis. Some dermatologists and physicians prefer to start treatment with topical agents to see the response in patients during first 2 months. Oral or injected medications are usually used in severe form of psoriasis, but due to severe side effects associated with this type of treatment, it is not used for long term.

Treatments can be divided broadly into 3 categories:

  • Topical treatment: mild to moderate cases
  • Phototherapy: moderate to severe cases
  • Oral or Injected medications: mostly in severe cases

Topical treatments

Following topical medications are usually used in the treatment:

  • Topical Corticosteroids: Helpful in reducing the inflammation and itching sensation. Ointments are recommended for skin problems and medicated foams for treating patches in scalp.
  • Vitamin D analogues: Helpful in resisting the growth of skin cells. Agents available are calcipotriene and calcitriol. Both are equally effective, but calcipotriene may cause skin irritation.
  • Vitamin A analogues: Reduces inflammation and mostly used in treating acne and sunburns. Tazarotene and acitretin are the two agents commonly used.
  • Anthralin: Reduces the abnormal growth of skin cells. It inhibits the DNA synthesis and also decreases the level of adhesion molecules which appears on endothelium. Anthralin may irritate the skin or cause a burning sensation which can be reduced by washing the affected area, half an hour after the application of ointment or cream.
  • Calcineurin inhibitors: Brings down the buildup of plaque and inflammation. Topical drugs in this class which can be used to treat psoriasis are tacrolimus and pimecrolimus.

Many more effective topical medications are available.

Phototherapy

Phototherapy is ideal for patients who can get relieved by sunlight exposure. As sunlight exposure is less in winter, phototherapy can be helpful in such situations. Some of the commonly used treatment methods are mentioned below.

  • Sunlight: The ultraviolet (UV) light kills the activated immune T cells in the skin, and thereby reduces the inflammation and scaling.
  • UVB Phototherapy: This artificial light source can alleviate the localized lesions. There are less intensive side effects in this treatment which can be managed by using moisturizers.
  • Psoralen plus ultraviolet A or PUVA: Photochemotherapy in which psoralen is used helps in deep reach of light (UVA) into the skin. It makes the skin more responsive and improves the skin health consistently throughout the course of treatment. Severe form of psoriasis can be benefited from this treatment.

This is a wide range of phototherapy methods for treating psoriasis effectively.

Oral/Injected Medications

The more severe form of psoriasis is benefited with certain drugs. Oral medications include:

  • Cyclosporine: A powerful immunosuppressant. But it increases the risk of other health problems, especially at higher doses.
  • Methotrexate: It blocks the cell metabolism, a most commonly prescribed medicine for psoriasis. It decreases the production of skin cells and restricts inflammation. It is also used in other conditions where abnormal cell growth is a problem.
  • Acitretin: Acitretin is a vitamin A derivative. It is considered a good choice when other therapies are not effective. It targets the retinoid receptors on the skin.
  • Other oral medications: Mycophenolate mofetil, hydroxyurea, tacrolimus and sulfasalazine are also used in the treatment of severe psoriasis.

Intravenous medications used to treat severe psoriasis are biologic therapies. Biologic therapies work by modification of immune response responsible for the development of psoriasis. The agents include

  • Infliximab
  • Etanercept
  • Alefacept
  • Efalizumab
  • Adalimumab
  • Golimumab

Some of the agents are self injectable while some are infused into the vein.

Psoriasis is a challenging skin disease. There may be times when some treatments give no effect and even worsen the condition. Based on the patient’s health and skin condition the doctor may make changes to the normal treatment approach. Certain lifestyle changes with proper nutrition and exercise may also be suggested. Psoriasis can definitely be managed well with systematic treatment.

  • References
    • 1. Bergstrom, Kendra Gail., and Alexa Boer. Kimball. 100 Questions & Answers about Psoriasis. Boston: Jones and Bartlett, 2005. 27-38. Print.
    • 2. Camisa, Charles. Handbook of Psoriasis. Malden, MA: Blackwell Pub., 2004. 7-35. Print.
    • 3. Kumar, Parveen J., and Michael L. Clark. Kumar & Clark Clinical Medicine. Edinburgh: W.B. Saunders, 2005. 1331-334. Print.
    • 4. Staff, Mayo Clinic. “Psoriasis – MayoClinic.com.” Mayo Clinic. Web. 12 Sept. 2011. <http://www.mayoclinic.com/health/psoriasis/DS00193>.

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