Definition:
Psoriasis is an immune-mediated inflammatory disease of the skin characterised by red scaly patches (psoriasis plaques). These plaques are areas of excessive skin cell production and inflammation caused by the increased ratio of cyclic GMP to cyclic AMP within the dermis. Newly generated cells rise to the skin's surface within days, accumulating in thick, crusty patches. Plaques frequently occur on the skin of the elbows and knees, but can affect any area, including the scalp and genitals. The disorder is a chronic or recurring condition which can vary in severity, from minor localised patches to complete body coverage. Fingernails and toenails are frequently affected (psoriatic nail dystrophy), as are the joints (psoriatic arthritis).
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 sports, and caring for family members or a home. Individuals with psoriasis may also feel self-conscious about their appearance and have a poor self-image.

Risk factors:
Factors that can contribute to the incidence of psoriasis include:
• The first outbreak is sometimes reported following stress/trauma or major infection.
• Familial/genetic predisposition
• Immune system diseases (including AIDS)
• Obesity
• Alcoholism
• Skin damage
• Rheumatoid arthritis
• Immune system dysfunction
• Infections
• Autoimmunity
• Genetic traits (portions of chromosomes 16, 17, 20, 6)
• Emotional stress
• Skin injuries/sunburn
• Certain drugs (chloroquine, gold, lithium, beta-blockers)
• Acidic foods
• Increased intracellular calcium levels and/or decreased intracellular magnesium levels
• Low zinc/high copper levels
• Possible B12, Folate, and iron deficiencies
• Changes in season and climate can trigger psoriasis outbreaks.
• Excessive alcohol consumption, smoking and recreational drug use may exacerbate psoriasis or make the management of the condition difficult

Signs and Symptoms:
Common signs and symptoms of psoriasis include:
• Raised skin lesions, deep pink with red borders and silvery surface scales; may be cracked and painful
• Blisters oozing aseptic pus
• Pitted, discoloured, and possibly thickened finger nails and/or toenails; may be separated from underlying skin
• Itching of skin around plaques
• Joint pain (psoriatic arthritis) in some cases
• New lesions may appear following injuries to the skin
• Sensitivity to friction and sweating
• Possible swelling of the affected areas