One of the most common misconceptions about psoriasis is that it is a contagious disease. Much of the uncertainty and fear people experience when seeing psoriasis for the first time comes from a fear of “catching it.” Psoriasis is not contagious and has no infectious component. No amount of skin-to-skin contact, caring for another person’s affected skin, or sharing of personal items such as towels or cups causes the trans-mission of psoriasis. Because there is no infectious cause, and the disease is caused by the white blood cells inside a person’s own body, no transmission is possible. Some psoriasis sufferers find it helpful to briefly explain what psoriasis is and why it is not contagious.
People who don’t understand the disease may confuse any rash with contagious infections like skin fungus (such as ringworm, athlete’s foot, or jock itch), impetigo (staph or strep infections of the skin), eczema, rashes due to viral infections, infestations such as mites or scabies, or even an imagined skin disease. If one person in a family has psoriasis and others are diagnosed with the disease later, the cause is thought to stem from a shared genetic predisposition and has no relation to physical contact.
Families can be reassured that physical contact with their loved ones is welcome and helpful for most psoriasis sufferers. The question of possible infection or contagiousness is a common one, and can be a source of much anxiety for sufferers and nonsufferers alike. Correct information about psoriasis, for family and friends as well as the community, can alleviate some of the misdirected fear associated with the disease. Psoriasis sufferers can prepare themselves with knowledge and techniques to explain the noninfectious cause of the disease.
Organizations such as the National Psoriasis Foundation have suggestions for talking about psoriasis for people of all ages. Clearing up this common misconception is often the most effective first step in talking about psoriasis. Although psoriasis is not contagious, it can spread and affect different parts of the skin. Psoriasis may begin anywhere on the body, but the most common places it appears and spreads are predictable. While every per-son is different, most people notice a similar pattern. The most common type of psoriasis, psoriasis vulgaris, has a characteristic appearance pattern on the elbows, knees, scalp, and trunk.
When a person has psoriasis in one location, a physician will usually check these common locations to see if psoriasis is present elsewhere. It can also appear any place the skin has experienced trauma, such as an old scar or new skin injury (discussed in Question 30). For most people, psoriasis appears in a symmetric pattern, though some may have only one or two areas of psoriasis on the skin. Although the majority of people have a typical pat-tern of plaque psoriasis, some people will have different types of psoriasis. Places where psoriasis may appear in a less common pattern include the skin folds under the armpits (see color plate H) and in the groin. This is called intertriginous psoriasis or inverse psoriasis.
Other types include palmar-plantar psoriasis, guttate psoriasis, pustular psoriasis, and erythrodermic psoriasis. Typically, only one type of psoriasis is present in an individual, though overlapping types may occur. In severe cases, psoriasis can spread to cover the entire body. When psoriasis causes redness covering over 90% of the body, it is called erythrodermic psoriasis, a serious and possibly life-threatening condition.
The involvement of the entire skin area impairs the body’s ability to fight off infection and keep moisture inside the skin barrier, and can increase the risk of infection. Depending on the severity of the psoriasis and a per-son’s overall health, this condition may warrant a hospital stay for monitoring and treatment. John’s comment: Thankfully it is not contagious. This fact is the foundation of being able to participate in society. It would be great if everyone in the United States knew this without having to mention it.