Psoriasis is a chronic condition that causes inflamed skin patches or lesions, which may be itchy or painful.
If you have white skin, the lesions may appear pink or red. If you have brown or black skin, the lesions may appear purple, grayish, or dark brown. The lesions are often covered in silvery white or gray scales.
Some people have mild psoriasis that affects relatively small areas of skin, while others have more severe psoriasis that affects more of the body.
Psoriasis primarily affects the skin but can also cause changes in the nails and joints.
Psoriasis typically causes inflamed patches of skin, which may itch or burn. The affected skin can vary in appearance, depending on your skin tone and the specific type of psoriasis you have.
Plaque psoriasis is the most common type of psoriasis. It causes raised scaly patches of skin, which typically develop in a symmetrical pattern on both sides of your body. It’s most likely to affect the scalp, elbows, or knees, but it may also affect other parts of your body.
Less common types of psoriasis include:
- guttate psoriasis, which causes small dot- or teardrop-shaped lesions
- pustular psoriasis, which causes pus-filled bumps surrounded by inflamed skin
- inverse psoriasis, which causes smooth inflamed patches where skin rubs together (e.g., in armpits)
- erythrodermic psoriasis, which causes inflamed scaly skin over most of your body
On white skin, the inflamed patches or lesions may appear pink or red. On black or brown skin, the inflamed patches may appear purple, grayish, or dark brown.
The affected skin may also crack or bleed, particularly if it gets scratched or is not well moisturized.
It’s possible to develop skin symptoms without nail or joint symptoms.
Nail psoriasis may cause changes in the appearance or texture of your fingernails or toenails, such as:
- yellow discoloration, particularly at the tips of your nails
- ridging, pitting, or crumbling of your nails
- separation of your nails from the nail bed
- blood under your nails
Some people develop nail psoriasis without skin symptoms.
Roughly 30% of people with psoriasis develop psoriatic arthritis, which causes joint swelling, stiffness, and pain.
In some cases, psoriatic arthritis may cause entire fingers or toes to swell. This is known as dactylitis. It can give your fingers or toes a sausage-like appearance.
Some people develop psoriatic arthritis without skin or nail symptoms.
If you have psoriasis, your recommended treatment will depend on your condition’s severity. Your doctor will evaluate the severity based on:
- the amount and location of affected skin
- whether you have symptoms in other parts of your body
- how severely the symptoms affect your routine activities or quality of life
Let your doctor know if you develop new or worse symptoms.
If you develop skin symptoms of psoriasis on less than 3% of your body, your doctor will likely consider the condition mild. For reference, the size of your palm is equal to about 1% of your body.
Mild nail psoriasis typically affects only one or two nails, with no serious symptoms. It may cause mild changes to the appearance and texture of your nails.
To treat mild skin or nail psoriasis, your doctor will likely prescribe topical corticosteroids, topical vitamin D analogs, or other topical treatments. These are treatments that you apply directly to your skin or nails.
If you develop skin symptoms of psoriasis on 3–10% of your body, your doctor will likely consider the condition moderately severe. They may also consider your psoriasis moderately severe if it covers less than 3% of your body but affects particularly sensitive areas, such as your face, palms, or genitals.
Moderate nail psoriasis typically causes moderate symptoms on more than two nails. It may cause moderately severe ridging, pitting, crumbling, and discoloration. Affected nails may separate from the nail bed.
To treat moderate skin or nail psoriasis, your doctor may start by prescribing topical therapies. In some cases, they may also prescribe phototherapy (light therapy) or systemic therapy, such as oral or injected medication.
If you develop skin symptoms of psoriasis on more than 10% of your body, the condition is considered severe.
Severe nail psoriasis typically causes severe symptoms on more than two nails. It may cause severe ridging, pitting, crumbling, and discoloration. The affected nails may separate from the nail bed.
Severe skin, nail, or joint symptoms may limit your routine activities and negatively affect your quality of life.
If you have severe psoriasis, your doctor may prescribe systemic therapy to reduce inflammation throughout your body. This may include one or more injected or oral medications.
Your doctor may also recommend topical therapies, phototherapy, or other treatments to help relieve symptoms.
In rare cases, people with psoriasis develop a severe form known as erythrodermic psoriasis. It causes a burn-like rash over 80–90% of the body. It may also cause severe skin peeling. Erythrodermic psoriasis requires emergency medical treatment.
Psoriasis causes inflamed skin patches or lesions that may be itchy or painful. It can also cause symptoms in other parts of your body, such as your nails and joints.
Mild psoriasis affects only a small portion of skin. Topical therapies, such as medicated shampoo, ointment, or cream, can typically treat it.
Moderate to severe psoriasis may affect larger areas of skin or particularly sensitive areas of skin. Severe psoriasis is also linked with an increased risk of psoriatic arthritis. Your doctor may prescribe systemic therapy and other treatments to manage moderate to severe psoriasis or psoriatic arthritis.
Let your doctor know if you develop new or worse symptoms of psoriasis, or if you notice changes in other parts of your body. They may recommend changes to your treatment plan.
You might need to try more than one treatment to find which one works well for you.