Psoriasis is generally an inherited skin condition by genetic testing there is a HLA-B27 or B28 gene that people with psoriasis posses. Psoriasis is often noted in children as white scaly patches on the knees, elbows, or scalp, but virtually can be on any part of the body. It appears pure white with silver glistening lesions that the upper layer can easily be scratched off with a finger nail coming off in sheets causing very minor bleeding. 1/3rd of the time it itches, it often goes unnoticed until the doctor observes it, notes it, or questions the patient. It generally is less noticeable in spring, summer and fall. It is more noticeable in the late fall and mostly in the winter as it generally improves with moderate sunlight and salt water and occasionally chlorinated water.
It usually, minimally presents and can flare and cover the body, and can even grow over parts of the eye and for no other reason it can vanish just as quickly as it appears. Psoriasis has certain triggers than can precipitate flares. Alcohol, lack of sunlight, spicy or hot foods, or abrading the erupted area can all lead to a much more intense response by the immune system. This is true of scratching or playing with the lesions, and you should try to avoid bothering the lesions. This is called Kubners phenomenon. It is non-contagious genetically inherited medical condition.
Interestingly psoriasis can often cause nail deformities mistaken as fungus and unsuccessfully self treated by a patient until they see a doctor. A different type of nail deformity called stippling is much like if you took a pencil and tapped on the external surface of the nail putting little dents in the nail. This is diagnostic of psoriasis. There is also ridging of the nails which looks like a Venitian blind closed and the edges of the blind ran the length of the nail from the cuticle to the tip of the finger.
The pathogenesis or background explanation, as to why psoriasis occurs is that cells in the skin that form by mitosis in the basement membrane of the skin and grow upward. Below the basement membrane are the blood vessels supplying nutrients and oxygen, as the cells grow upward in layers the oxygen gets less and less to the cells and eventually die off and slough off as part of the epidermis this is normal skin growth.
In a normal course of an injury, you may scrape your elbow and the usual repair mechanism takes place leaving a close resemblance of the original skin matrix. Patients with psoriasis may have the exact same scrape to the elbow that might have 30 cells layers above the basement membrane. This is supplied by the vascular system, however, the genetic program in these patients instead of re-growing 30 layers of cells, re-grows 200 layers of cells and the vascular supply was not designed for this magnitude and simply cannot support this increased thickness. The layers of dead skin now manifest as the traditional dried, scaly, white psoriasis lesions.
John Drew Laurusonis
Doctors Medical Center