Is That Rash Psoriasis, or Is It Something Else?

Plaque psoriasis is the most common form of the chronic skin condition, affecting about 80 percent of people with psoriasis. Plaque psoriasis usually starts as small red bumps on the skin. It then develops into red patches with a silvery, scaly coating — these raised patches are called plaques. Plaques usually show up on elbows, knees, and the lower back, and they can last for months or even years without treatment.

The rash caused by guttate psoriasis  — the second most common type of psoriasis — is characterized by multiple small, round red spots on the skin, usually widespread across the trunk and limbs. Often resulting from a bacterial or viral infection in children, such as strep throat, these spots come on suddenly and sometimes require oral medication or injections. Mild cases, however, may clear up without treatment.

A psoriasis skin rash tends to itch, burn, and feel sore. Patches of psoriasis commonly occur on your knees and elbows. Many people also have scalp psoriasis. The common skin rash seborrheic dermatitis (pictured) also causes scaly, itchy skin patches. It can occur on your scalp, where it may be called dandruff, or on your face and chest. While doctors don’t know the exact cause of seborrhea, it occurs across the age spectrum, in babies as well as in adults, and is usually treated with creams and lotions.

Pityriasis rosea (pictured) causes a red skin rash that is scaly and can look like guttate psoriasis. This skin rash is common in children and young adults. It often begins with cold-like symptoms and is followed by red, scaly, and sometimes itchy oval-shaped patches that appear on your back or abdomen. Like psoriasis, this skin rash is not contagious. Doctors do not know the exact cause, but pityriasis rosea may be due to a viral or bacterial infection. You can take medication to relieve the itching, and the rash should go away after a few weeks to months. And unlike psoriasis, this skin rash rarely comes back.

Like psoriasis, eczema (pictured) is a chronic skin condition that often causes intense itching. Scratching causes redness and inflammation of the skin, leading to a worsening of the eczema. Scratching can also cause a secondary bacterial infection. The most common type of eczema is caused by a reaction to irritants like detergents, soaps, or household cleansers. So if you have eczema, you should be careful to use mild soap and regularly moisturize your sensitive skin. Your doctor may prescribe a steroid cream or other medications if eczema is severe.

Some forms of psoriasis appear as pus-filled blisters that may be confused with pimples. Pustular psoriasis forms white blisters that are filled with pus and surrounded by red skin. Far more common than psoriasis, acne also causes a pus-filled pimple eruption. However — unlike psoriasis — acne is caused by excess oil, blocked pores, and bacteria. Acne is common in teens and young adults and occurs on the face, neck, back, or chest. Pustular psoriasis is usually seen in adults and can occur anywhere on the body, but it’s less likely on the face.

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Like guttate psoriasis, measles also follow symptoms of an upper respiratory infection in children and cause a skin rash of small, red spots. However, the measles skin rash usually starts on the face and spreads down to cover the body and is accompanied by fever, cough, and a runny nose. Measles rash is also flat, while the rash of psoriasis is typically raised. Measles is caused by a virus and is contagious, though the measles vaccination has made this a rare disease in the United States.

Shingles is another viral infection that shares some symptoms with psoriasis. Like psoriasis, shingles can make your skin burn and itch and produces a red, blistered skin rash. Shingles is caused by the same virus that first brings on chickenpox. The virus stays in your body and can come back years later to cause shingles, especially during times of stress or infection. The skin rash of shingles follows the course of a single nerve, usually on the trunk. In some cases, severe pain lasts long after the burning, itchy rash disappears. Shingles is more common in people over age 50.

Tinea is a type of fungal infection that resembles some symptoms of psoriasis. Psoriasis can cause the thick fingernails symptomatic of fungal nail infections, and both can cause red, itchy skin rashes. When tinea grows on your skin, it can cause a scaly, red skin rash that clears in the middle, called ringworm. Fungal infections of the skin and nails can be hard to treat. Antifungal medications work, but you may need to take them for a long time.

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Inverse psoriasis is a type of psoriasis that forms in the armpits and skin folds under breasts or in groin areas, making the skin red and shiny. Sweating makes this type of psoriasis worse. Heat rash also makes your skin red and forms in skin folds of the groin, breasts, and armpits. Heat rash occurs in hot, humid conditions. Sweating can cause your pores to get blocked and results in a bumpy, red skin rash that stings. Heat rash is more common in newborns but can also affect older children and adults.

Dry, cracked skin is a psoriasis symptom. However, dry air can also cause your skin to become dry and itchy. When the skin is dry and irritated, it’s more likely to get infected. Infection may cause your skin to become red and swollen. If you have any skin rashes that keep coming back or won’t go away, see your doctor. Most cases of psoriasis can be diagnosed with a physical examination; but because psoriasis can look like many other skin conditions, a skin biopsy may have to be done to definitively diagnose it.