PSORIASIS

PSORIASIS-Everything You need to know 

Edited by, JOHN FELIX

Psoriasis is a non-communicable, chronic, painful, itchy, disfiguring and disabling disease. The symptoms of psoriasis may subside totally and may exacerbate again during the course of the disease. Psoriasis is derived from the Greek words "Psora-meaning itching" and "sis-meaning condition". The patient may have a lifelong illness that may be emotionally distressing. There is no cure for Psoriasis. Treatment may help to reduce the frequency of episodes and may relieve symptoms.

EPIDEMIOLOGY:

Psoriasis is spread worldwide. It can affect any gender and any age group. Majority of patients have their onset at two age groups (i.e. 20-30 Years and 50-60 Years of age).

ETIOLOGY:

Psoriasis is a T-Lymphocyte mediated inflammatory disease. Genetic predisposition coupled with some precipitating factor triggers abnormal immune response. This results in psoriasis skin lesions. Keratinocyte proliferation is the major cause for psoriasis symptoms.

Genetics, autoimmune reactions, Infections, injury to skin, Medications (such as Lithium, anti-malarial, propranolol and indomethacin), stress and smoking are the risk factors for Psoriasis.

PATHOPHYSIOLOGY:

The skin consists of 3 layers namely Epidermis, dermis and hypodermis. Epidermis is the outermost layer of skin.

 Epidermis is composed of Four sub layers,

               • Stratum Corneum

               • Stratum granulosum

               • Stratum Spinosum

               • Stratum Basale

Epidermis is composed of Keratinocytes which is produced in basal layer just above the epidermis, and migrate to skin surface in 28-30 days.

Due to any one or more Etiologic factors such as injury, trauma or infections the immune system gets activated. The immune cells such as dendritic cells, macrophages and T-Cells gets activated within dermis.

These immune cells moves to epidermis from dermis and secretes chemical mediators such as IL-36ץ, TNF∝, IL-1ß, IL-6 etc. This causes epidermal hyperplasia and improper cell maturation leading to pre-maturation of keratinocytes. Pre-mature keratinocytes fail to release adequate lipids. These lipids are generally a cement adhesive of corneocytes. Lack of these lipids forms poorly adherent Stratum Corneum. This results in Flaking and scaly presentation of Psoriasis.

Skin cells are produced every 3-5 days in psoriasis patients rather than the usual 28-30 days. Due to over production of cells, the cells buildup on the skin surface forming thick patches, plagues and other characteristics of psoriasis.

TYPES:

Psoriasis may be classified into different types namely;

• Plaque psoriasis - Raised inflamed red patches on skin

• Guttate psoriasis- Small psoriatic papules 

• Inverse Psoriasis- Occurs in the folded areas of skin like Knee, Elbow, and Armpit

• Pustular Psoriasis- Pus filled lesions

• Psoriatic arthritis- Psoriasis in the joints

• Erythrodermic Psoriasis- Superficial scaling that appears like burns

• Nail Psoriasis- Occurs in nails

DIAGNOSIS:

• Physical Examination

• Psoriatic Area and Severity Index (PASI) to classify the severity of Psoriasis as mild, moderate and severe.

TREATMENT:

Though this disease cannot be cured, treatment may help reduce the symptoms and to reduce the frequency of exacerbations. Proper counselling should be given to the patient to reduce stress. 

• Phototherapy or Photochemotherapy for severe cases

• Topical corticosteroids such as Hydrocortisone butyrate 0.1% cream may be used. Topical corticosteroids are available in the form of lotions, creams, gels, foams, shampoo and solutions.

• Vitamin D analogues like Calcipotriol is used in mild cases of psoriasis. They inhibit Keratinocyte differentiation and production

• Retinoids: Tazarotene is a topical retinoid. They normalize the abnormal keratinocyte differentiation and proliferation.

• Salicylic acid: This is used as an adjuvant therapy to reduce scaling

• Coal tar has anti-inflammatory property and reduces keratinocyte proliferation

• Calcineurin Inhibitors: This is effective in treating Plaque psoriasis.