The Skin Center
Laguna Hills, CA 92653
Original article by Dena Thompson, BS, MA and Dr. Nili N. Alai, MD, FAAD ( New 08/08/09)
What is Pityriasis Rosea?
Pityriasis Rosea is a common rash usually seen in younger individuals between the ages of 10 to 35 years old. The rash typically lasts six to eight weeks, with rare cases extending twelve weeks or longer. Once a person has Pityriasis Rosea, it generally does not recur in their lifetime.
Pityriasis Rosea characteristically begins as an asymptomatic single, large, pink patch called the “herald patch” or mother patch measuring 2-10 centimeters. The herald patch is a dry, pink to red patch which appears on the back, chest, or neck and has a well-defined, scaly border.
One to two weeks following the initial appearance of the herald patch, a person will then develop many smaller, pink patches across their trunks, arms, and legs. The second stage of Pityriasis Rosea erupts with a large number of oval spots, ranging in diameter from 0.5 centimeters (size of a pencil eraser) to 1.5 centimeters (size of a peanut). The individual spots form a symmetrical “Christmas tree” pattern following lines of cleavage. This rash is usually limited to the trunk, arms, and legs, rarely occurring on the face and neck. Pityriasis Rosea generally spares the face, hands, and feet.
Who gets Pityriasis Rosea?
Pityriasis Rosea is, for the most part, equally common between the two sexes, although there is slightly higher occurrence reported in women. It generally occurs in children and young adults, between the ages of 10-35 years old. Pityriasis has no racial predominance. Most people only get Pityriasis once in their lifetime, although it is theoretically possible to have it more than once.
What are signs and symptoms of Pityriasis Rosea?
Most people do not notice any symptoms with Pityriasis Rosea except for the appearance of the rash itself. Mild, intermittent itching is reported in about 50% of cases, especially when people become overheated from exercise or hot showers. Itching seems to increase with stress. Sometimes Pityriasis is accompanied by flu-like symptoms, such as sore throat, fatigue, nausea, aching, and decreased appetite. Most people are otherwise in very good health and don’t feel any other symptoms.
What causes Pityriasis Rosea?
The exact cause of Pityriasis Rosea remains unknown. Most recently, Pityriasis has been associated most strongly with a virus from the human herpes family called Human Herpes virus Type 6 (HHV6). Pityriasis is not caused by or known to be associated with the common types of herpes virus that cause genital or oral herpes. While the mode of transmission (how it gets passed between people) of Pityriasis Rosea is also unknown, respiratory contact has been postulated. Pityriasis does not seem to be directly or immediately contagious to close contacts or medical providers exposed to the rash. Most people with a known exposure to Pityriasis do not seem to contract the rash.
Pityriasis is not an allergic reaction, sign of an internal disease, or a bacterial or fungal infection. Currently, Pityriasis Rosea is thought to be most likely a viral associated rash due to the possible concurrence with mild flu-like symptoms and the fact that people tend to gain potential immunity after one outbreak…
How is Pityriasis Rosea diagnosed?
Pityriasis Rosea is usually diagnosed by the skin appearance, particularly the onset of the distinct, large “herald patch”, and the symmetrical, “Christmas tree” orientation of the following outbreaks. Also, the “herald patch” tends to have a unique, fine scale with a definite border. To rule out other types of skin disorders, a physician may scrape the skin and use a quick prep fungal test called potassium hydroxide or “KOH” to rule out fungus. Also, blood tests including Rapid Plasma Reagent “RPR” may be done to rule out secondary syphilis, which may mimic Pityriasis. In some cases, a skin biopsy may be required and performed to rule out fungus and other types of rashes.
Tests to rule out other causes of rashes that may mimic Pityriasis Rosea:
- Potassium hydroxide “KOH”- fungal prep of skin
- Blood test : Rapid Plasma Reagent “RPR”- to exclude secondary Syphilis
- Skin biopsy
What are some common misdiagnoses of Pityriasis Rosea?
The first “Herald patch” of Pityriasis Rosea may look very similar in appearance to ringworm (Tinea corporis). However, upon treatment with a topical antifungal, there will be no improvement. Pityriasis has also been mistaken with eczema and psoriasis, which can occur as similar scaly patches, but not in the same distribution as Pityriasis Rosea. A secondary reaction from syphilis also produces a similar rash, which can be ruled out by a blood test.
- Fungal infection “Tinea corporis”
- Secondary Syphilis
- Drug Eruption
- Fixed Drug Eruption
- Pityriasis Lichenoides Chronica
- HIV associated rash
How is Pityriasis Rosea treated?
Most cases of Pityriasis Rosea require no treatment and resolve spontaneously. Treatment is not necessary if the rash is completely without any symptoms. Typically, Pityriasis will usually clear on its own in six to eight weeks without medical intervention or therapy.
The most common symptom is itching, which can be treated with topical steroid creams and oral antihistamine. These will not shorten the duration of the rash, but will decrease the itching. Another treatment for itching is UVB light or sunlight. However, exposure to sun light increases the risk of skin cancer. Generally, the best treatment is to avoid being overheated by reducing exercise and avoiding hot showers and baths.
- Topical steroid creams (like hydrocortisone cream, clobetasol cream, etc.)
- Oral antihistamines (like diphenhydramine (Benadryl), loratidine (Claritin), etc.)
- Natural sunlight 10-15 minutes per day
- Avoid overheating
- Avoid hot showers
There has been some evidence of reduced duration of Pityriasis Rosea with the off- label use of the antibiotic erythromycin, or off-label use of antiviral medications such as acyclovir (Zovirax) or famciclovir (Famvir). However, neither of these medications has been proven to be uniformly effective in the treatment of Pityriasis Rosea, and is not usually necessary or required for treatment.
What home remedies can I use for Pityriasis Rosea?
Home remedies of Pityriasis Rosea include taking lukewarm baths or showers, avoiding drying soaps, wearing cotton or silk clothing to reduce heat, and taking oatmeal baths. Calamine or menthol lotions can also be helpful for itching.
- · Lukewarm baths
- · Lubricating with bland moisturizers
- · Oatmeal baths
- · Calamine or menthol lotions
- · Steroid creams ( hydrocortisone cream)
- · Diphenhydramine (Benadryl) oral pills or liquid for itching
- · Natural Sunlight exposure to body parts10-15 minutes per day
Can Pityriasis Rosea be prevented?
There is no definitive prevention for Pityriasis Rosea, as the cause is not yet fully known. As with most viral infections, helpful prevention tips may include good basic hygiene, hand washing, and avoidance of ill contacts and of aerosolized respiratory droplets from people coughing or sneezing.
What is the prognosis for Pityriasis Rosea?
The general prognosis for Pityriasis is excellent as most cases clear even without treatment by 6-8 weeks.
Pityriasis Rosea will in nearly all cases clear completely on its own, with or without medical treatment. It typically leaves no long-lasting scars, although some mild, temporary skin discoloration called post inflammatory hypopigmentation or hyperpigmentation can occur in people with darker skin. It has no known long-lasting side effects and has not been associated with any other diseases.
Symptoms may be reduced with topical treatment or taking extra precaution to prevent overheating, and the rash will usually clear on its own in 6-8 weeks. Once a person has Pityriasis Rosea, they generally have lifelong immunity.
Where can I find more information and facts about Pityriasis Rosea?
A good source of information is the American Academy of Dermatology: www.aad.org or a Board-Certified Dermatologist.
Pityriasis Rosea at a Glance
- Begins as a single, large, pink patch found on the trunk called the “herald patch”
- Followed 1-2 weeks later with smaller pink patches in a “Christmas tree” formation
- Generally asymptomatic except for the appearance
- Mildly itchy in 50% of cases
- Clears spontaneously in average of 6-8 weeks
- Sometimes accompanied by mild, flu-like symptoms
- May mimic fungal infections called ringworm (Tinea corporis)
- No long-lasting health effects
- Not directly contagious
- Lifelong immunity after one episode of Pityriasis Rosea
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