Psoriasis vs. Seborrheic Dermatitis: What You Should Know

Medically reviewed by Steve Kim, MD on January 21, 2016Written by Ann Pietrangelo on January 21, 2016

Nobody wants an itchy, flaky scalp, but it’s a fairly common problem. Before you can figure out how to treat this symptom, you have to identify the cause.

Two conditions that can lead to itchy scalp are psoriasis and seborrheic dermatitis.

Psoriasis is a chronic skin disease. It can cause skin cells to grow so quickly that they accumulate on the surface of your skin. Patches of rough, scaly skin can appear anywhere on your body, including the scalp.

Seborrheic dermatitis is another skin condition that can cause rough, scaly skin on the scalp and face. The common name for seborrheic dermatitis is dandruff. In babies, it’s called cradle cap.

What Are the Symptoms of Psoriasis?

Psoriasis looks like patches of thick, red skin with silvery scales. The patches can appear anywhere on your body, especially on the elbows and knees. They can also show up on your scalp. The patches can be itchy or tender to the touch.

What Are the Symptoms of Seborrheic Dermatitis?

Seborrheic dermatitis is usually found on the scalp, but it can sometimes appear elsewhere. It causes itchy patches of scaly skin that may look a little greasy but can flake, especially if you scratch.

In babies, seborrheic dermatitis may be crusty. Scales may appear red, brown, or yellow. Babies may also have dermatitis around the eyes and nose. If the skin is scratched, there’s some risk of bleeding or infection.

How Can You Tell the Difference?

Psoriasis and seborrheic dermatitis of the scalp share many common symptoms. They both result in red patches of skin, flakes that may attach to the hair shaft, and itching.

How can you tell the difference? One clue is in the scales. Psoriasis on the scalp produces thick, silvery scales. The scales of seborrheic dermatitis are usually thinner. They’re more likely to be white or yellow, with a greasy appearance.

Understanding Psoriasis Scales

As for the patches, if you have psoriasis, it’s very likely that you have them on other parts of your body. If you scratch or try to remove them, they’ll probably bleed. Seborrheic dermatitis patches are usually easy to remove. Psoriasis patches sometimes feel sore or tender, but seborrheic dermatitis doesn’t.

It’s possible to have both scalp conditions at the same time.

Who Develops These Conditions?

Anyone can get psoriasis of the scalp. It’s more likely to occur in adults who have psoriasis elsewhere on their body. The exact cause of psoriasis isn’t known, but it involves an overreaction of the immune system. It tends to run in families, so it’s likely there’s a genetic link.

There’s no known way to prevent psoriasis.

Anyone can get seborrheic dermatitis, too. However, men get it more often than women. Some things that may play a role in getting seborrheic dermatitis include:

  • a family history of seborrheic dermatitis
  • oily skin
  • using alcohol-based products
  • weather extremes
  • stress
  • fatigue

Neither condition is contagious.

How Is Seborrheic Dermatitis Treated?

Treatment may depend on the severity of your condition. Everyone responds differently to medication, so it may take a few tries to find the right solution for you.

For some people, dandruff clears up on its own. Over-the-counter (OTC) shampoos and medication are usually enough to improve flaking and soothe itching. If not, ask your doctor about prescription-strength products.

In babies, cradle cap doesn’t always require treatment. It generally resolves well before the first birthday. In the meantime, use a mild baby shampoo. Massage the scalp gently using a very soft brush. You should be gentle because breaking the skin can lead to infection. If you’re concerned about your baby’s scalp, see your pediatrician.

How Is Psoriasis Treated?

Psoriasis of the scalp may be harder to treat. Topical corticosteroids may help reduce inflammation and slow the growth of skin cells.

Psoriasis can also be treated with light therapy. Systemic treatment may be beneficial for stubborn psoriasis. This may involve injectable medications. It may take a combination of treatments to get psoriasis under control.

Severe Psoriasis: Managing a Flare-Up

Do You Need To See a Doctor?

If you have a mild case of flaky skin on your scalp, OTC dandruff products may help. If it doesn’t, you should probably have a doctor take a look.

See your doctor if you have undiagnosed patches of skin that look abnormal in other places on your body.

Your doctor will likely be able to tell whether it’s psoriasis, seborrheic dermatitis, or something else, just by examining your skin. It might take looking at a skin sample under a microscope to confirm. In rare cases, a biopsy is needed.

Psoriasis is a chronic condition, which means you have it for life. With a proper diagnosis, you can learn to monitor and manage it.

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