Where Does Psoriasis Usually Start?

Medically Reviewed on 6/3/2022
Psoriasis is a chronic skin condition that typically causes areas of thickened, scaly, red, and inflamed skin called plaques.

The most common sites of psoriasis are the scalp, elbows, and knees, although psoriasis can involve any part of the body such as the face, palms, soles, and back.

  • Psoriasis lesions typically appear as symmetrical lesions called plaques that are areas of red, thickened skin with silvery scales.
  • In skin folds (flexural psoriasis), such as in the groin, buttocks, or under the breasts, the silvery scales may be absent, and the lesions have a shiny appearance and moist peeling surface.
  • The exact appearance of lesions, however, may vary depending on the type of psoriasis.

Psoriasis lesions generally have minimal itching. In some people, however, itching may be severe, leading to repeated scratching and thickening of the skin and giving it a leathery and pigmented appearance (lichenification). The skin may become dry, cracked, and irritated with a tendency to blee. 

Nails are affected in almost half of the people with psoriasis. Nail psoriasis can result in pitted, deformed nails. The nails may become fragile and even separate from the nail bed. Studies report that people with nail psoriasis have a high likelihood of having joint damage called psoriatic arthritis.

What is psoriasis?

Psoriasis is a chronic skin condition that typically causes areas of thickened, scaly, red, and inflamed skin called plaques.

  • Although psoriasis generally affects adults, it can occur in children and adolescents.
  • Psoriasis is not transmitted from one person to another (noncontagious).
  • Symptoms may vary depending on the severity and type of psoriasis.

What causes psoriasis?

The exact cause of psoriasis is unknown. Research suggests that the condition is caused by an overactive immune system in which the person’s immunity targets their skin instead of restricting itself to fighting diseases and infections.

  • Excessive immune system activity leads to rapid growth and multiplication of skin cells.
  • This proliferation is too fast for the body to compensate through shedding resulting in the piling up of cells and the formation of the typical plaques on the skin.

Moreover, genes may play a role in causing psoriasis. Certain conditions such as stress, injury, infections, dry skin, and some medications may play a role in causing psoriasis flare-ups.


Psoriasis causes the top layer of skin cells to become inflamed and grow too quickly and flake off. See Answer

6 major types of psoriasis

Major types of psoriasis include:

  • Plaque psoriasis: It is the most common type of psoriasis accounting for about 80 to 90 percent of the cases. It presents as typical psoriasis plaques with silvery scales. The plaques may vary in size, and the smaller ones may fuse to form larger plaques. Although it can occur anywhere, plaque psoriasis primarily affects the scalp, elbows, lower back, or knees.
  • Guttate psoriasis: It is characterized by the sudden appearance of small, scaly, salmon to pink bumps on the skin mainly over the arms, torso, and legs. The lesions typically clear on their own in a few weeks to months. 
  • Pustular psoriasis: As the name suggests, the lesions appear as small, pus-filled bumps. The pus, however, is not due to an infection. The lesions mainly appear on the hands and feet. In severe cases, the pustules may appear on most of the body surface needing medical attention.
  • Nail psoriasis: It causes pitted, deformed, and easily breakable nails. In severe cases, the nails become crumbly and even separate from the nail bed.
  • Erythrodermic psoriasis: It is a rare and serious condition that requires urgent medical attention. The skin on most of the body appears burnt, and the person appears fatigued and extremely sick. They may have severe itching, rapid pulse, chills, and fever
  • Inverse psoriasis: It is also called flexural or intertriginous psoriasis. It typically affects the skin folds such as in the groin, buttocks, armpits, or under the breasts.

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Medically Reviewed on 6/3/2022
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