More than 8 million Americans live with psoriasis, a chronic skin condition which typically causes red, scaly plaques that sometimes itch, burn or sting.
The exact cause of psoriasis isn’t entirely clear, but it appears that both the immune system and genetics are involved. The plaques or patches seen in people with psoriasis are caused by a build up of skin cells that are growing at a rate much faster than normal. A psoriasis outbreak typically happens in response to a trigger of some kind. Common triggers, according to the National Psoriasis Foundation, include stress, skin injury, certain medications and infection.
There are five official types of psoriasis:
It is possible for a person to have more than one type of psoriasis, with each type having its own unique features.
Plaque psoriasis is the most common type of the condition, according to the American Academy of Dermatology.
- Where it occurs: The knees, elbows, scalp and lower back are the areas most often affected, though plaque psoriasis can appear anywhere on the body.
- Symptoms: The telltale signs of plaque psoriasis are raised red lesions with silvery scales that are itchy and sometimes painful.
- Treatment options: Daily baths, moisturizers (heavy, ointment-based), light therapy, steroid creams, topical tar preparations, oral medications and injections are all possible treatment options for plaque psoriasis.
This is the second most common type of psoriasis. If you have a psoriasis outbreak shortly after a strep infection and notice small, red lesions on your trunk or another area of your body, it may be guttate psoriasis.
- Where it occurs: The small red spots of guttate psoriasis develop mostly on the torso, arms and legs.
- Symptoms: The small red spots can be widespread and have a scaly appearance, but they are not as thick as typical plaque psoriasis.
- Treatment options: Light therapy, steroid creams and oral medications are typically successful treatments for guttate psoriasis. Treating the underlying infection can also help.
Inverse psoriasis commonly occurs in people who also have another form of psoriasis. For example, people with plaque psoriasis who gain weight are more likely to develop inverse psoriasis.
- Where it occurs: Inverse psoriasis develops exclusively in the areas where skin rubs against skin, such as the groin, armpits, around the genitals and on the underside of the breasts.
- Symptoms: A rash from inverse psoriasis is still red, but it’s smooth and raw, rather than scaly and bumpy. It can also feel sensitive to touch.
- Treatment options: Topical corticosteroids or calcineurin inhibitors are the primary treatments for inverse psoriasis.
Pustular psoriasis features small, pus-filled blisters that develop quickly. The pus consists of white blood cells and is not infectious. When generalized pustular psoriasis develops in a person with plaque psoriasis, it may have been triggered by getting an infection or stopping corticosteroid medication too quickly.
- Where it occurs: The hands and feet are the most common areas to develop an outbreak of pustular psoriasis, but it can appear anywhere on the body. It may cover only a small area or a more widespread one.
- Symptoms: Pustular psoriasis begins as red, tender skin that turns into pus-filled blisters within a couple hours. It tends to clear up within a few days before coming back.
- Treatment options: Steroid cream (for smaller patches), oral medications and light therapy (once blisters resolve) are all effective treatments for pustular psoriasis. Eliminating triggers, if possible, is also helpful.
Erythrodermic psoriasis is the rarest but most severe form of the disease. This type of psoriasis is most common in people who have unstable plaque psoriasis and can be triggered by medications including corticosteroids, severe sunburn and the presence of other types of psoriasis.
- Where it occurs: Erythrodermic psoriasis affects the entire body.
- Symptoms: Those with erythrodermic psoriasis may experience a peeling red rash that is intensely itchy and extremely painful.
- Treatment options: Medicated wet dressings, oral medication and topical steroids are all treatment options for erythrodermic psoriasis. Severe cases of erythrodermic psoriasis tend to require a combination of treatments and hospitalization.
- About Psoriasis, National Psoriasis Foundation, 2019, https://www.psoriasis.org/about-psoriasis
- Causes and Triggers, National Psoriasis Foundation, 2019, https://www.psoriasis.org/about-psoriasis/causes
- Types of psoriasis: Can you have more than one?, American Academy of Dermatology, 2018, https://www.aad.org/diseases/psoriasis/psoriasis-types
- Slide show: Types of psoriasis, Mayo Clinic, 2019, https://www.mayoclinic.org/diseases-conditions/psoriasis/multimedia/psoriasis-pictures/sls-20076486?s=1