Psoriasis is a skin disease, often marked by red scaly patches. There are several different types of psoriasis. In most cases, people have one type at a time. Sometimes symptoms go away. Then, another type of psoriasis crops up in response to a trigger. Here is a brief overview of the main types of psoriasis.
Plaque psoriasis is the most common type of psoriasis. About eight in 10 people with psoriasis have this type. It is also sometimes known as psoriasis vulgaris.
Plaque psoriasis causes raised, inflamed, red skin covered by silvery white scales. These may also itch or burn. Plaque psoriasis can appear anywhere on your body but often appears in these areas:
- Lower back
Rather than coming and going, plaque psoriasis may last for years.
Guttate psoriasis often starts suddenly in childhood or young adulthood. It occurs is less than 2% of cases. This type causes small, pink-red spots on the skin. Usually less thick than plaque lesions, they often appear in these areas:
- Upper arms
These things may trigger guttate psoriasis:
- An upper respiratory infection such as strep throat or tonsillitis
- Skin injury
- Certain drugs such as beta-blockers
This type of psoriasis may go away within a few weeks, even without treatment. However, some cases are more stubborn and require treatment.
Inverse psoriasis appears as bright-red, smooth, shiny lesions. These don't have scales. Inverse psoriasis usually appears in these areas:
- In the armpits
- In the groin
- Under the breasts
- In skin folds around the genitals or buttocks
Because of its location, inverse psoriasis may worsen from sweating and rubbing. For this reason, it can be hard on overweight people or those with deep skin folds. An overgrowth of yeast may trigger this type of psoriasis.
Pustular psoriasis is uncommon and mostly appears in adults. Pustular psoriasis causes pus-filled bumps (pustules) surrounded by red skin. These may look infectious, but they are not. Reddening can appear first, followed by scaling and the formation of the pus-filled bumps.
This type of psoriasis may show up in one area of the body such as the hands and feet. Or it may cover most of the body (generalized). Pustular psoriasis can be very serious, so immediate medical attention is needed. Generalized pustular psoriasis can cause:
- Fast heart rate
- Muscle weakness
These things may trigger pustular psoriasis:
- Topical or systemic medications, especially steroids
- Sudden withdrawal of systemic medications or strong topical steroids used over a large area of the body
- Overexposure to ultraviolet (UV) light without sunscreen
- Exposure to certain chemicals