Pityriasis Rosea: Causes, Is It Contagious, and How Many Weeks Until It Clears
Pityriasis rosea (also called pityriasis rosea or “rose-colored scaly rash”) is a self-limiting inflammatory skin rash. It begins with one large pink oval patch on the trunk, called the “herald patch”, and within 1–2 weeks smaller oval spots follow, arranged along the back like the branches of a Christmas tree. The rash fades on its own over 6–8 weeks, sometimes up to 12 weeks, and is not a serious contagious disease.
Pityriasis rosea is most common between the ages of 10 and 35 and affects both men and women. Although it is usually harmless, there are three situations that dermatologists take especially seriously: a rash that looks like secondary syphilis, a rash that occurs during pregnancy, and a pityriasis rosea-like rash caused by medication. This article explains what each type of rash looks like, how to tell it apart from similar conditions, the medicines doctors use, their doses, and how long the rash takes to clear.
What causes pityriasis rosea?
The exact cause of pityriasis rosea is still unknown, but current evidence points to the “reactivation” of human herpesvirus 6 and 7 (HHV-6 and HHV-7), which most people picked up unknowingly in childhood. These viruses are not the same as the viruses that cause cold sores or genital herpes.
Common timing: during seasonal changes, the rainy season and the cool season; small clusters of cases sometimes occur at certain times.
Associated triggers: fatigue, lack of sleep, stress, or a recent cold or sore throat before the rash appears.
About 5% of patients have cold-like symptoms before the rash appears, such as headache, fatigue, sore throat or a low-grade fever.
It is not caused by fungus, so antifungal creams do not clear it.
It is not caused by poor hygiene, food, or “forbidden foods”.
In a small number of patients the rash looks exactly like pityriasis rosea but is actually caused by a medicine or vaccine. Doctors classify this as a separate group and manage it differently (see the section on pityriasis rosea-like rash from medicines and vaccines below).
Pityriasis rosea symptoms: day by day until the rash fades
Pityriasis rosea follows a fairly clear sequence, which is the most important clue for diagnosis.
Day 1: the herald patch appears as a single spot on the trunk, upper arm or neck. Patients often think it is ringworm because it is a scaly ring.
Days 7–14: smaller spots 0.5–1.5 centimeters across appear in crops, mostly on the back, chest, abdomen, upper arms and thighs.
Weeks 2–3: new spots can keep appearing. Itching is usually at its worst during this stage.
Weeks 4–6: new spots stop appearing, the color fades and the scaling lessens.
Weeks 6–8: most of the rash disappears. Some people are left with faint dark or pale marks that slowly fade over several months.
About 1 in 5 people have a rash that lasts longer than 12 weeks. If it lasts more than 3 months, it should be re-examined by a doctor.
About half of patients have itching, ranging from mild to severe enough to disturb sleep. Itching often gets worse after a hot shower, after exercise that causes sweating, or when wearing rough clothing.
What does the herald patch look like?
Appearance: a single oval or round patch about 2–10 centimeters across, most often 2–5 centimeters, salmon-pink in color with a slightly raised edge and a thin ring of scale just inside the border (collarette scale). The center is often paler than the edge.
Cause: this is the first place the skin reacts to the reactivated virus. It is seen in about 50–90% of patients.
Severity/urgency: not dangerous, but this is the stage most often misdiagnosed as ringworm. If a steroid-antifungal cream is applied and the smaller spots then follow, patients often think the medicine made the rash spread.
When to see a doctor: if you are unsure whether it is ringworm or pityriasis rosea, a doctor can examine skin scrapings under the microscope for fungus (KOH) in a few minutes. Do not guess and keep applying creams. For more on the differences, see our article What causes ringworm.
Secondary eruption in a Christmas-tree pattern
Appearance: small oval spots 0.5–1.5 centimeters across, from a few dozen to several hundred. The long axis of each oval follows the skin's natural fold lines, so on the back they form an inverted V that looks like the branches of a Christmas tree (Christmas tree pattern). Each spot has fine scale inside its edge like the herald patch, but is smaller.
Cause: this is the stage when the rash spreads across the trunk after the herald patch. It usually does not appear on the face, palms or soles.
Severity/urgency: not dangerous, but if itching is severe or disturbs sleep or work, it should be treated for symptoms.
When to see a doctor: if there is a rash on the palms or soles, mouth sores, patchy hair loss, or swollen lymph nodes in several places, a blood test to rule out secondary syphilis is always needed, because the two conditions look very similar.
Atypical pityriasis rosea: no herald patch, or rash on the face, arms, legs or skin folds
Appearance: about 10–50% of patients never see a herald patch. Some have only a few spots. Others have most of the rash on the face, neck, armpits, groin and limbs instead of the trunk, called inverse pityriasis rosea. Some have a rash on only one side of the body, or unusually large patches.
Cause: it is the same disease, but each person's body responds differently.
Severity/urgency: not more severe than the typical form, but much harder to diagnose and much more easily confused with other conditions.
When to see a doctor: anyone whose rash does not follow the usual sequence should see a doctor, because drug rash, syphilis, psoriasis and eczema need to be ruled out first.
Pityriasis rosea with raised bumps, blisters or pinpoint bleeding
Appearance: instead of flat oval scaly patches, the rash consists of small raised bumps 1–5 millimeters across (papular), clear blisters (vesicular) or purple-red pinpoint bleeding spots (purpuric). Some people have red spots or shallow sores inside the mouth.
Cause: the papular form is common in young children, pregnant women and people with darker skin.
Severity/urgency: the rash itself still clears on its own, but it looks very similar to other conditions such as drug rash, chickenpox or inflamed blood vessels (vasculitis).
When to see a doctor: everyone should see a doctor, especially if there are blisters, pinpoint bleeding spots, mouth sores, fever or a general feeling of being unwell.
Pityriasis rosea in children
Appearance: older children and teenagers usually have the typical form, while young children are more likely to have the papular form and to have the rash on the face, arms and legs than adults.
Cause: the same as in adults. Children do not catch pityriasis rosea from classmates at school.
Severity/urgency: usually mild and clears on its own in 6–8 weeks. Children can go to school as normal and do not need to be isolated.
When to see a doctor: if the child has a fever, is drowsy, eats poorly, has a rash on the palms or soles, or has blistering. Antihistamines and steroid creams for children must be dosed by a doctor according to body weight. Do not confuse it with “roseola” in babies, which is a different disease (see the frequently asked questions).
Pityriasis rosea during pregnancy
Appearance: looks like typical pityriasis rosea. Some women have the papular form and a more extensive rash than usual.
Cause: pregnancy makes it easier for the HHV-6/HHV-7 viruses to reactivate.
Severity/urgency: this is the one situation in which pityriasis rosea needs more attention than usual. Some studies have found a higher risk of miscarriage or preterm birth, especially when the rash appears in the first 15 weeks of pregnancy and covers much of the body, although most pregnant women with pityriasis rosea deliver normally.
When to see a doctor: pregnant women who suspect pityriasis rosea should see a doctor to confirm the diagnosis and have a blood test to rule out syphilis, and must always tell their obstetrician so that closer monitoring of the pregnancy can be considered. The choice of medicines during pregnancy must be decided by a doctor only.
Pityriasis rosea-like rash from medicines and vaccines
Appearance: pink oval scaly patches spread over the trunk like pityriasis rosea, but usually with no herald patch. The rash is more dusky red or purple, itchier, and may appear on the face, arms and legs.
Cause: it appears after starting certain medicines, such as ACE inhibitor blood-pressure drugs (for example captopril), NSAID pain relievers, the acne drug isotretinoin, metronidazole and some targeted therapies. It has also been reported after certain vaccines, such as influenza and COVID-19 vaccines.
Severity/urgency: usually not dangerous, and the rash clears faster once the medicine responsible is stopped. This differs from a severe drug reaction with fever, peeling skin or mouth sores.
When to see a doctor: if the rash appears within a few weeks of starting a new medicine, take all your medicines to a doctor. Do not stop regular medicines for chronic conditions on your own, and if you have fever, skin blistering or mouth sores, go to a hospital immediately. Read more about drug rash.
Is pityriasis rosea contagious?
In practical terms, pityriasis rosea is not considered contagious. There is no need to separate from others, stay away from school or work, or keep personal items apart. Although a virus is involved, most people already carry this virus from childhood, so the rash comes from the virus reactivating in the person's own body rather than catching a new infection from those around them.
People in the same household can occasionally have it at the same time, but this is uncommon.
Pityriasis rosea is not a sexually transmitted disease.
Swimming and exercise are fine as usual, but take a cool shower after sweating to reduce itching.
Is pityriasis rosea dangerous?
In most patients, pityriasis rosea is not dangerous, does not spread to internal organs, and clears on its own without scarring. About 2–3% have a recurrence later. What makes pityriasis rosea “look dangerous” usually comes down to these three things.
Misdiagnosis: a rash that is actually secondary syphilis is mistaken for pityriasis rosea and goes untreated.
Pregnancy: the obstetrician must be told, as explained above.
Using the wrong treatment on your own: applying strong steroid cream over the whole body for a long time, or taking steroid tablets on your own, thins the skin, causes the rash to come back, and masks the signs of other diseases.
How many weeks does pityriasis rosea take to clear?
Most pityriasis rosea clears on its own within 6–8 weeks from the day the herald patch appeared. Some people take 10–12 weeks, and a few take up to 5 months.
Duration does not indicate severity. A more extensive rash does not necessarily take longer to clear.
Dark or pale marks after the rash has cleared are not rash that is still present, and no further treatment is needed for them.
If new spots keep appearing after 8 weeks, or the rash lasts more than 12 weeks, a doctor should reassess it, because it may not be pityriasis rosea but, for example, psoriasis or pityriasis lichenoides, which can last for months to years.
Telling pityriasis rosea apart from similar conditions
The key to managing pityriasis rosea is being able to tell that it is not another condition, as these are treated completely differently.
Secondary syphilis: also an oval reddish-brown rash on the trunk, but usually with no herald patch, often with a rash on the palms and soles, little itching, and possibly mouth sores, patchy hair loss, swollen lymph nodes and a history of a genital sore 2–6 months earlier. A blood test (VDRL/RPR together with TPHA) is needed. See also secondary syphilis rash.
Ringworm (tinea corporis): a clearly raised ring with scale at the outer edge, very itchy, usually only a few rings that slowly expand, and not in crops arranged in a Christmas-tree pattern. Skin scrapings show fungus.
Guttate psoriasis: small round red bumps 2–10 millimeters across with thick silvery-white scale, usually appearing 2–3 weeks after a bacterial sore throat, with no herald patch. Read more about psoriasis.
Drug rash: a rash that appears after starting a new medicine, a red rash that spreads quickly, very itchy, possibly with fever.
Nummular eczema: coin-sized round patches with weeping or crusted skin, very itchy, more on the arms and legs than the trunk. See also nummular eczema.
Pityriasis versicolor: pale or brown spots with fine scale on the back and chest, not very itchy, long-lasting and recurring every hot season.
Rash from acute HIV infection: a widespread red rash together with fever, sore throat and swollen lymph nodes, within 2–4 weeks after a risk exposure.
How doctors diagnose pityriasis rosea
Pityriasis rosea is diagnosed mainly from how the rash looks and the order in which it developed. No blood test confirms the disease directly. Doctors order additional tests only when necessary.
Skin scraping for fungus (KOH): when only the herald patch is present, or the rash looks like ringworm. It takes a few minutes.
Blood test for syphilis (VDRL/RPR and TPHA): when there is no herald patch, there is a rash on the palms and soles, there are sexual risk factors, or the patient is pregnant.
HIV blood test: when there has been a risk exposure in the past 1–3 months.
Skin biopsy: when the rash does not follow the usual sequence, lasts more than 12 weeks, or another condition is suspected.
Review of medicines: every medicine started in the 2 months before the rash appeared, including any recent vaccines.
Treating pityriasis rosea: medicines doctors use
Pityriasis rosea clears on its own, so the goals of treatment are to reduce itching and inflammation and, in some people, to shorten how long the rash lasts. The medicines dermatologists commonly use are as follows.
Moisturizers and dry-skin creams: fragrance-free creams or lotions applied twice a day and after every bath, used for as long as the rash lasts. They help reduce scaling and itching in everyone.
Non-drowsy antihistamines: cetirizine 10 milligrams or loratadine 10 milligrams taken once a day by adults while itching is present, usually for 1–4 weeks. If itching is so bad that it prevents sleep, a doctor may prescribe a drowsy type at bedtime instead. For children, the dose is based on body weight.
Medium-strength steroid creams such as triamcinolone acetonide 0.1% twice a day, or mometasone furoate 0.1% once a day, applied only to the very itchy patches, for no more than 2 weeks at a time, and not on the face, skin folds or groin without consulting a doctor. Itching usually improves within 3–7 days.
Antiviral acyclovir 800 milligrams, 5 times a day for 7 days: there is moderate-level evidence that it helps the rash clear faster and reduces itching, especially when started in the first week of the rash. Doctors consider it for people with an extensive rash, severe itching or general symptoms. The dose must be adjusted in people with reduced kidney function. It is not a medicine everyone needs.
Narrowband ultraviolet B (narrowband UVB) light therapy: for people with severe itching or a rash that lasts a long time, given 2–3 times a week for 2–4 weeks. It is available at hospitals or facilities with a phototherapy unit, and the doctor will refer you when needed.
What doctors do not routinely recommend: oral steroids, because they may make the rash last longer or come back after stopping, and antifungal creams or tablets, because pityriasis rosea is not caused by fungus. As for antibiotics such as erythromycin, study results are still conflicting, so they are not used as standard.
How to tell the treatment is working: itching eases within 1 week, no new spots appear after weeks 3–4, and the rash keeps fading. If you have followed the plan and still have severe itching, or new spots keep appearing, go back to the doctor for reassessment. The choice of medicine, dose and duration of use is the decision of the examining doctor.
Self-care while waiting for pityriasis rosea to clear
Bathe in lukewarm or cool water for no more than 10 minutes. Hot water makes itching worse and the rash redder.
Use a gentle soap and do not scrub the skin or use a loofah or scrub.
Apply moisturizer within 3 minutes after bathing, while the skin is still slightly damp.
Wear loose cotton clothing and avoid rough fabrics or wool.
Avoid strenuous exercise that leaves you drenched in sweat for the first 2–3 weeks. If you do exercise, take a cool shower right afterward.
Do not scratch. Keep your nails short and use a cool cloth as a compress when itchy.
There is no need to avoid any foods. Pityriasis rosea has nothing to do with “forbidden foods”.
Dark and pale marks after pityriasis rosea clears
In Asian people and people with darker skin, pityriasis rosea often leaves marks after the rash settles.
Dark marks (post-inflammatory hyperpigmentation): common in people who scratched or whose rash was very inflamed. They slowly fade over 3–6 months, and in some people take up to 1 year.
Pale marks (post-inflammatory hypopigmentation): spots lighter than the surrounding skin, which usually regain their color within several weeks to several months. This is not vitiligo.
How to help the marks fade faster: apply sunscreen SPF 30 or higher to areas exposed to the sun, stop scratching, and get the itching under control quickly.
Do not use skin-lightening products on your own while the rash is still inflamed, as they cause irritation and can make the marks darker.
When to see a doctor
Most pityriasis rosea can be managed at home, but you should see a dermatologist if any of the following apply.
You are not sure it is pityriasis rosea or you cannot see a herald patch.
You have a rash on the palms or soles, mouth sores, or patchy hair loss.
You have a genital sore, or a sexual risk exposure in the past 3 months.
You are pregnant or may be pregnant.
The rash appeared after starting a new medicine or having a vaccine.
You have fever, blisters, pinpoint bleeding spots, or feel generally unwell.
The itching is so bad you cannot sleep, or new spots are still appearing after 8 weeks, or the rash has lasted more than 12 weeks.
For other skin conditions that cause ring-shaped rashes, see our collection of skin condition articles.
Quick summary
Pityriasis rosea begins with one oval herald patch, followed within 1–2 weeks by a Christmas-tree pattern of smaller spots on the back.
It clears on its own in 6–8 weeks, sometimes up to 12 weeks, and is not contagious in practical terms.
Treatment is for symptoms: moisturizer, the antihistamine cetirizine 10 mg, a medium-strength steroid cream for no more than 2 weeks, and acyclovir in some people at the doctor's discretion.
It must always be told apart from secondary syphilis if there is no herald patch, there is a rash on the palms and soles, or there is a sexual risk exposure.
Pregnant women must tell their obstetrician, especially if the rash appears in the first 15 weeks.
No foods need to be avoided, and you should not apply antifungal creams or take steroid tablets on your own.
Frequently asked questions about pityriasis rosea
What causes pityriasis rosea?
Pityriasis rosea is believed to be caused by the reactivation of human herpesvirus 6 and 7 (HHV-6, HHV-7), which most people have carried in their bodies since childhood. It usually occurs when the body is run down, stressed, short of sleep, or during a change of season. It is not caused by fungus, poor hygiene or food. A small number of people have a rash that looks like pityriasis rosea but is caused by a medicine or vaccine, so the doctor always asks about medicines used in the 2 months before the rash appeared.
Is pityriasis rosea dangerous or contagious?
In general it is not dangerous. The rash clears on its own in 6–8 weeks, does not spread to internal organs, leaves no scars, and is not considered contagious in practical terms, so you can go to school and work as normal. The groups who need to be careful are pregnant women, who must tell their obstetrician, and people with a rash on the palms and soles or a sexual risk exposure, who need a blood test to rule out secondary syphilis because the two look very similar.
What foods should you avoid with pityriasis rosea?
There are no foods you need to avoid with pityriasis rosea. There is no evidence that eggs, chicken, seafood or “forbidden foods” make the rash spread or clear more slowly. You can eat a balanced diet as normal. What you should really avoid are things that make itching worse: hot baths, scrubbing the skin, exercising until drenched in sweat without showering, and alcoholic drinks while itching is severe. People who already have an allergy to a particular food should still avoid it as before.
What cream should you apply for pityriasis rosea?
The creams doctors commonly use are a daily moisturizer together with a medium-strength steroid cream such as triamcinolone acetonide 0.1% twice a day or mometasone furoate 0.1% once a day, applied only to the itchy patches for no more than 2 weeks at a time. If itching is widespread, an oral antihistamine such as cetirizine 10 mg once a day is usually added. Do not apply antifungal creams or multi-ingredient combination creams on your own, because pityriasis rosea is not a fungus, and strong steroid cream applied over the body for a long time thins the skin.
Is pityriasis rosea related to AIDS?
Pityriasis rosea is not caused by the HIV virus and is not a sexually transmitted disease. However, two conditions that look like pityriasis rosea are related to sexual contact: secondary syphilis rash and the rash of acute HIV infection. If you have had a risk exposure in the past 1–3 months, there is no herald patch, there is a rash on the palms and soles, or there is fever or sore throat, the doctor will recommend blood tests for syphilis and HIV. These are easy tests that help ensure you are treated for the right disease. Read more about the rash from HIV.
What is roseola?
Roseola (roseola infantum or exanthem subitum) is a different disease from pityriasis rosea. It occurs in babies and young children aged 6 months to 2 years and is caused by a first infection with the HHV-6 virus. The child suddenly develops a high fever for 3–5 days, and when the fever settles, a rash of small red spots appears on the trunk and clears within 1–2 days. It is not itchy. Pityriasis rosea, on the other hand, occurs in teenagers and adults, has no high fever, and the rash lasts for several weeks. If a baby has a high fever, is drowsy or has a seizure, see a doctor immediately.
Related reading: Ringworm · Secondary syphilis rash · Psoriasis · Drug rash · Nummular eczema · Atopic dermatitis
This article provides general medical information and is not a substitute for diagnosis by a doctor. The choice of medicine and dose depends on the individual assessment of the examining doctor.
Written by Dr. Patara Voravutinon, Dermatologist · Last reviewed 14 November 2026
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