Psoriasis (pronounced 'sore-EYE-ah-sis') is a common, often chronic, non contagious disease of the skin characterised by dry, scaly patches of various sizes. These have definite boundaries and may be covered by grey, white or silvery scales. It is found in about 1% of the population with Caucasians seeming to be more affected than others. Its course follows an inconsistent pattern, with chronic periods being followed by remission or exacerbation of differing onset and duration. It is among the oldest recorded diseases of humanity. The Greeks called it psora (meaning to itch) and lepra (meaning a scale or flake). In China it has been known by several names including bai bi (white dagger sore), song pi xuan (loose or pine skin dermatosis) and gang xuan (dry skin dermatosis).
Its cause in Western medicine is still unclear, although hereditary links have been suggested. It can be triggered by infections, cuts, stress, reaction to some drugs and diet. In Chinese medicine, psoriasis is seen as a result of the invasion of Pathogenic Wind (an energetic process where a negative external factor enters the body, especially through the skin) which affects the blood and yin of the body; or as an internal stagnation of blood and chi caused primarily by an imbalance in the emotions. Due to the chronic nature of the condition, clients often present with complex combined patterns of disharmony, most probably an underlying weakness or deficiency complicated by an overt excess - the flaring up of the lesion itself, often a manifestation of what is termed a fire toxin in Chinese medicine. A careful study of the client's history may give clues as to what the causative factor of the disease is. For many people psoriasis can be a highly distressing condition, both due to the nature and location of the lesions. Chinese medicine can be of use in that a combination of therapy, exercise and dietary advice can attack the condition on many fronts.