Autoimmune disease. A breakdown of the body's immune system, which defends you against infections. The immune system mistakenly attacks your own cells. This can cause an autoimmune disease like psoriasis.
Erythrodermic psoriasis. A serious type that affects most of the body. Symptoms include red or purple skin, lots of shedding, itching, pain, and body temperature that goes up and down. An outbreak usually requires you go to the hospital. It is the least common type but also the most severe.
Guttate psoriasis. The second most common type, mostly found in children and young adults. The spots are much smaller and not as thick as those of plaque psoriasis. They usually show up on the trunk, arms, and legs. They often happen suddenly with a cold or other respiratory infection, or after tonsillitis or strep throat.
Immune system. Your body's natural defense system, which helps fight infections. When the immune system mistakenly attacks your body's own cells, it is called an autoimmune response -- which can trigger an autoimmune disease like psoriasis.
Inverse psoriasis. A type found in skin folds such as the armpit, groin, beneath breasts, and buttocks. It appears as shiny, smooth, red sores.
Non-steroid topicals. These are treatments such as creams where the key ingredient is something other than a steroid such as anthralin, calcineurin inhibitors, coal tar, roflumilast (Zoryve), salicylic acid, tapinarof (Vtama), vitamin A derivative, or vitamin D3.
Phototherapy. A treatment that involves brief exposures to ultraviolet light -- ultraviolet A (UVA) or B (UVB).
Plaque. Patches of scaling skin that cover sores. They usually appear on the elbows, knees, and trunk.
Plaque psoriasis. The most common type. Eighty percent of people with psoriasis have this kind. It appears as raised, inflamed, red or purple patches with silvery, white, or red scaly skin. Most often on the elbows, knees, lower back, and scalp.
Psoralen and UVA light therapy (PUVA). A treatment that involves taking medication called psoralen, which makes your skin more sensitive to light, before a brief exposure to ultraviolet A (UVA) rays.
Psoriatic arthritis. A type of arthritis that may happen in someone with psoriasis. The fingers and toes are most often affected. People with pustular psoriasis or psoriasis of the nails are more likely to develop this type. Ten percent to 30% of people with psoriasis get it.
Pustular psoriasis. A type with non-infectious, pus-filled pimples in red skin. It can be very painful, and you may need to go to the hospital.
Topical medications. Ointments, creams, and solutions that are applied to your skin. Topical medications used for psoriasis include anthralin, calcineurin inhibitors, coal tar, corticosteroids, retinoids, roflumilast (Zoryve), tapinarof (Vtama), vitamin D3,and vitamin A derivatives.