Pityriasis rosea (PR) is a common skin condition that causes a rash similar to that seen in other skin diseases, including ringworm, psoriasis and eczema. The lesions may also be confused with those seen in people with secondary syphilis, a sexually transmitted disease.
The exact cause of PR remains unknown. Although it is not usually contagious, scientists suspect it may be caused by a virus. However, research has been unable to confirm this theory.
Most cases of PR occur in healthy individuals without signs of illness. It occurs more frequently in women than men, and usually affects children and young adults ages 10 to 35. The skin disease has a higher incidence during the spring and fall.
PR is generally benign, self–limited and does not require medical treatment. Lesions usually disappear on their own in eight to 16 weeks.
About pityriasis rosea
Pityriasis rosea (PR) is a common skin condition characterized by the appearance of a scaly and sometimes itchy rash throughout the body. Common sites for the PR rash include:
Neck
Chest
Back
Arms
Upper thighs
PR was first identified in 1798 by British physician Robert Willan, who called it “roseola annulata” and described it as a self–limited eruption in otherwise healthy children. In 1860, French physician Camille Melchior Gibert gave the skin disease its present name: pityriasis, which stands for scaly, and rosea, which stands for the color pink. Pink patches of scaly skin appear on various parts of the body, usually beginning on the back.
Most cases of pityriasis rosea occur in healthy individuals without signs of illness. It is more common in women than men, and a vast majority of the time the disease affects children and young adults ages 10 to 35. However, it may occur at any age. The skin disease has a higher incidence during spring and fall.
Generally, PR is benign, self-limited and usually resolves on its own within eight to 16 weeks. The most common complications of PR are changes in the skin’s pigment (color), such as post-inflammatory hyperpigmentation (excessive pigmentation) and hypopigmentation (skin discoloration) in the affected areas. However, these conditions are normally not permanent and resolve on their own over time. Individuals with dark skin may also have long-lasting flat, brown spots after the rash has subsided. The condition does not cause scars.
PR may be confused with the lesions seen in secondary syphilis, a sexually transmitted disease. The use of certain drugs (e.g., antibiotics, heart medications, barbiturates) may cause some people to develop skin eruptions that resemble PR. In addition, the PR rash is similar to that seen in other skin disorders, including:
Ringworm. A skin infection caused by a fungus.
Psoriasis. A common skin inflammation resulting in scaly patches of itchy, dry skin.
Eczema. A chronic skin disorder characterized by an itchy and scaly rash.
Potential causes and risk factors
The exact cause of pityriasis rosea (PR) remains unknown. Although it is generally not thought to be contagious, scientists suspect it may be caused by a virus. Certain aspects of the appearance of PR symptoms commonly occur with viruses. These include:
PR tends to occur along with upper respiratory infections.
Many times, more than one person in a household may develop PR.
People who come in contact with infected patients often develop PR.
It is commonly seen in people with compromised or weakened immune systems, although, it also affects healthy individuals with no sign of disease.
It occurs seasonally, more often during the fall and spring.
Once a person gets PR, he or she tends to develop lifelong immunity.
Despite these similarities to viral conditions, no single virus has been identified as a cause of PR. Though, there is supporting data that the rash is caused by human herpes virus (HHV) type 7. Research has shown that treating PR with an antiviral decreases the length of the rash to two weeks as opposed to the normal length which can be eight to 16 weeks in the majority of cases.
Risk factors for developing PR include:
Gender. Women are more likely to develop the skin disease than men.
Age. The skin disorder tends to occur more often in children and young adults, especially those ages 10 to 35.
Signs and symptoms of pityriasis rosea
Pityriasis rosea (PR) usually begins with a large, dry and scaly, reddish-pink patch on the chest, back or abdomen, or less often on the upper arms, neck or thighs. This patch is known as a “herald patch” because it precedes the skin condition. Its average size ranges from 1 to 1 1/2 inches (2 to 4 centimeters), but it can be larger or smaller. Sometimes the herald patch appears without any previous symptoms, but some people may experience malaise (a general feeling of illness), including loss of appetite, fever, fatigue and joint pain a few days beforehand.
Within five to 10 days, more patches appear on the chest, back, arms and upper thighs. They may be light pink to deep red in color. Patches may also occur on the neck, but usually not on the face. The patches are oval and may form a symmetrical pattern over the back that resembles the outline of a Christmas tree, which is why the disease is commonly referred as “Christmas tree rash”. The number and size of the patches varies from patient to patient.
Although rare, oral lesions or ulcers may also occur in people with PR. Some people have atypical symptoms of PR, which may include patches in body folds such as the armpits, abdomen and groin areas, and sometimes the face. Known as inverse pityriasis rosea, this condition occurs more commonly with younger children and African Americans.
Sometimes the disease can produce a severe and widespread skin eruption. In most cases patients will experience some itching (pruritus), especially when exposed to warm temperatures. Physical activities such as jogging and running, or bathing in hot water, may cause the rash to temporarily worsen or become more obvious. The rash usually fades and disappears on its own within eight to 16 weeks, but can sometimes last up to five months or more.
PR can mimic other, more serious disorders. Therefore, patients displaying signs and symptoms of the condition should consult a physician.
Diagnosis methods for pityriasis rosea
Pityriasis rosea (PR) is diagnosed based on a visual examination of the skin rash, particularly the initial “herald patch,” and patient symptoms. A physician will perform a complete physical examination and compile a thorough medical history when trying to make a diagnosis. If the physician suspects PR, he or she may refer the patient to the care of a dermatologist, a physician who specializes in the medical treatment of skin disorders.
In cases where diagnosis is unclear after examination, a physician may perform diagnostic tests, including:
Blood tests. Laboratory analysis of a patient’s blood may be necessary to exclude secondary syphilis, a sexually transmitted disease that causes a rash similar to that seen with PR. Results from the blood test will also indicate the presence of any medications or drugs (e.g., antibiotics, barbiturates) that may cause similar skin eruptions.
Tissue sample. A physician may scrape the skin or perform a biopsy to take a sample of the affected area for microbiological analysis to rule out diseases with similar lesions, including ringworm, psoriasis and eczema.
Treatment and prevention for pityriasis rosea
Generally, pityriasis rosea (PR) clears up on its own in about eight to 16 weeks and does not require medical treatment. However, over-the-counter anti-itch creams or ointments such as calamine lotion may be used to relieve pruritus (itching). In cases of severe itching, a dermatologist may recommend the following:
Phototherapy (e.g., ultraviolet B light therapy, moderate sun exposure). This type of treatment may help speed clearing of the lesions. However, it should only be performed under physician’s orders and extreme care must be taken to avoid sunburn and/or hyperpigmentation.
Evidence from a small study suggests that drugs used to treat herpes infections may also effectively shorten the duration of pityriasis rosea symptoms.
Patients should not use any over-the-counter or prescription medications without first consulting a physician.
Patients may also help relieve the itching that usually accompanies the skin rash by:
Using gentle liquid cleansers
Applying cool compresses
Bathing in Epsom salts or baking soda
Soaking in colloidal oatmeal baths
Applying baking soda (mixed with cool water) to the rash
Using moisturizers or emollients after bathing
In addition, avoiding certain irritants may also relieve or minimize itching. Patients should avoid:
Hot showers or baths
Antibacterial or drying soaps
Fabrics that irritate the skin (e.g., wool, acrylic)
Strenuous activity should also be avoided because it also can aggravate the rash.
Because the causes of PR are unknown, there are no known ways to prevent the condition.
Questions for your doctor
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions regarding pityriasis rosea (PR):
Do my symptoms indicate PR?
What tests will you use to determine the cause of my symptoms?
What may have caused me to develop PR?
Does PR pose any danger to my overall health?
What PR-related complications may I develop?
What are my treatment options and how effective are they?
Can I spread PR to other parts of my body or to other people?
