Pityriasis rosea typically begins with an oval, slightly raised, scaly patch — called the herald patch — on the face, back, chest or abdomen. Before the herald patch appears, some people have headache, fatigue, fever or sore throat.

A few days to a few weeks after the herald patch appears, you may notice smaller bumps or scaly spots across your face, back, chest or abdomen that look like a pine-tree pattern. The rash can cause itching.

See your health care provider if you develop a rash that gets worse or hasn't cleared up in three months.

The exact cause of pityriasis rosea is unclear. It might be triggered by an infection with a virus, particularly by certain strains of the herpes virus. But it's not related to the herpes virus that causes cold sores. Pityriasis rosea isn't contagious.

Having family members with pityriasis rosea increases your risk of developing the condition. Taking certain medicines may increase the risk of this condition as well. Examples include terbinafine, isotretinoin, omeprazole, gold, arsenic and barbiturates.

Complications of pityriasis rosea aren't likely. If they do occur, they may include:

• Severe itching
• Temporary spots (lasting weeks to months) of skin that are darker or lighter than usual (post-inflammatory hyperpigmentation or hypopigmentation), which is more likely in people with brown or Black skin

In most cases, your health care provider can identify pityriasis rosea by looking at the rash. You might need a scraping or possibly a skin biopsy, which involves taking a small piece of the rash for testing. This test can help tell a pityriasis rosea rash from other, similar rashes.

Pityriasis rosea usually goes away on its own without treatment in 4 to 10 weeks. If the rash doesn't disappear by then or the itching bothers you, talk with your health care provider about treatments. The condition clears up without scarring and usually doesn't come back.

Medications

If home remedies don't ease symptoms or shorten the duration of pityriasis rosea, your health care provider might prescribe medicine. Examples include corticosteroids and antihistamines.

Light therapy

Your health care provider might also suggest light therapy. In light therapy, you're exposed to natural or artificial light that may ease your symptoms. Light therapy may cause lasting spots of skin that are darker than usual (post-inflammatory hyperpigmentation), even after the rash clears.

The following self-care tips may help relieve the discomfort of pityriasis rosea:

• Take nonprescription allergy medicine (antihistamines), such as diphenhydramine (Benadryl, others).
• Bathe or shower in lukewarm water. Sprinkle bath water with an oatmeal-based bath product (Aveeno).
• Apply a moisturizer, calamine lotion or a nonprescription corticosteroid cream.
• Protect your skin from the sun. Apply a broad-spectrum sunscreen with an sun protection factor (SPF) of at least 30, even on cloudy days. Apply sunscreen generously, and reapply every two hours — or more often in you're swimming or perspiring.

You're likely to start by seeing your health care provider. You might then be referred to a doctor who specializes in skin disorders (dermatologist).

Here's some information to help you get ready for your appointment.

What you can do

• List any symptoms you're experiencing, including those that seem unrelated to the reason for which you scheduled the appointment.
• List key personal information, including whether you're pregnant or have any major illnesses, stresses or recent life changes.
• Make a list of all medications, vitamins and supplements you're taking, including the dosage information.
• List questions to ask your health care provider.

Questions to ask your health care provider about pityriasis rosea include:

• What's the most likely cause of my symptoms?
• What are other possible causes for my symptoms?
• I have another health condition. Could it be related to the rash?
• Is this rash temporary or long lasting?
• Will this rash leave permanent scars?
• Will the rash cause permanent changes in skin color?
• What treatments are available, and which do you recommend?
• Will treatment for the rash interact with other treatments I'm receiving?
• What are possible side effects of this treatment?
• Will the treatment help ease the itching? If not, how can I treat the itching?

What to expect from your doctor

Your health care provider may ask:

• When did you first begin to notice the rash?
• Have you had this type of rash in the past?
• Are you experiencing symptoms? If so, what are they?
• Have your symptoms changed over time?
• Does anything seem to improve your symptoms?
• What, if anything, appears to worsen your symptoms?