Psoriasis is the most common autoimmune disease in the United States, affecting as many as 7.5 million Americans. The disease typically strikes between the ages of 15 and 35, and causes skin redness and irritation.
Psoriasis can appear suddenly or slowly and can go away and come back again.
People with psoriasis most often experience raised, thick red skin with flaky silver-white patches on the body that bleed and itch, called scales. Patches are most often seen on the elbows, knees, and middle of the body, but can appear anywhere including the scalp, according to the National Institutes of Health.
Psoriasis is not contagious. There are five common types of psoriasis each of which seem to be passed down through families in about one third of the cases. However researchers still aren't clear on the precise details of the psoriasis-associated genetic links.
Statistics show that if a parent has psoriasis, a child has about a 10 percent chance of also developing it. In sets of identical twins, if one twin has psoriasis, the likelihood that the other twin will also develop psoriasis is around 70 percent. For a pair of non-identical twins the chance of the second twin getting psoriasis is 20 percent.
Some researchers now believe about 10 percent of the general population inherits one or more of the genes that create a predisposition for psoriasis, but that only 2 to 3 percent of this group actually goes on to develop the disease, reported Everyday Health.
The cause of psoriasis isn’t fully known,but it's thought to be related to the immune system sending out faulty signals that speed up the growth cycle of skin cells. The Mayo Clinic reported that psoriasis can start or worsen when a susceptible person is exposed to certain triggers.
Triggers for psoriasis include:
- Infections (such as strep throat)
- A skin injury (a cut, scrape bug bite or severe sunburn)
- Cold weather
- Heavy alcohol consumption
- Certain medications