However, it can affect males and females of any age. Many people with pityriasis rosea have no other symptoms, but the rash sometimes follows a few days after an upper respiratory viral infection cough, cold, sore throat or similar. The herald patch is a single plaque that appears 1—20 days before the generalised rash of pityriasis rosea. It is an oval pink or red plaque 2—5 cm in diameter, with a scale trailing just inside the edge of the lesion like a collaret. Pityriasis rosea: herald patch Pityriasis rosea.
A few days after the appearance of the herald patch, more scaly patches flat lesions or plaques thickened lesions appear on the chest and back. A few plaques may also appear on the thighs, upper arms and neck but are uncommon on the face or scalp. These secondary lesions of pityriasis rosea tend to be smaller than the herald patch. They are also oval in shape with a dry surface. Like the herald patch, they may have an inner collaret of scaling. Some plaques may be annular ring-shaped.
Pityriasis rosea plaques usually follow the relaxed skin tension lines or cleavage lines Langer lines on both sides of the upper trunk. The rash has been described as looking like a fir tree. It does not involve the face, scalp, palms or soles. Pityriasis rosea: secondary rash Pityriasis rosea. Pityriasis rosea is said to be atypical when diagnosis has been difficult. Atypical pityriasis rosea may be diagnosed when the rash has features such as:.
Pityriasis rosea is associated with reactivation of herpesviruses 6 and 7, which cause the primary rash roseola in infants. Influenza viruses and vaccines have triggered pityriasis rosea in some cases. Pityriasis rosea or atypical, pityriasis rosea-like rashes can rarely arise as an adverse reaction to a medicine. Patches on the back are often vertical and angled to form a "Christmas tree" or "fir tree" appearance. Mild itching is a problem for about half of the people who get the rash. The rash usually lasts 6 to 8 weeks, but it can last up to several months.
How is pityriasis rosea diagnosed? How is it treated? If the rash lasts more than 3 months, contact your doctor. To relieve itching at home: Try to stay cool. Getting too warm and sweaty can make the rash and itching worse. Avoid taking hot showers or baths. Keep the water as cool as you can tolerate. Add a handful of oatmeal ground to a powder to your bath. Or you can try an oatmeal bath product, such as Aveeno.
Use the cream very sparingly on the face or genitals. Note: Do not use the cream on children younger than age 2 unless your doctor tells you to. Do not use in the rectal or vaginal area in children younger than age 12 unless your doctor tells you to. Try an over-the-counter antihistamine , such as a nondrowsy one like loratadine Claritin or one that might make you sleepy like diphenhydramine Benadryl.
Don't give antihistamines to your child unless you've checked with the doctor first. Apply a moisturizer or calamine lotion to the skin while it is damp. Use as little soap as possible. Use gentle soaps, such as Basis, Cetaphil, or Dove.
Avoid deodorant soaps when you have a rash. Other papulosquamous dermatoses. In JC Hall, ed. Philadelphia: Lippincott Williams and Wilkins. Muncaster A Pityriasis rosea. In MG Lebwohl et al.
Edinburgh: Saunders Elsevier. If the GP is uncertain, they may refer you to a skin specialist dermatologist. Pityriasis rosea usually gets better without treatment within 12 weeks.
Treatment is not needed unless you experience discomfort and itching. It's not known what causes pityriasis rosea. One theory is that the rash may be caused by a viral infection. Pityriasis rosea is not contagious and cannot be spread to other people through physical contact.
Pityriasis versicolor is another common skin condition that can be confused with pityriasis rosea, as the rash may look similar. But there are important differences between these 2 conditions.
Pityriasis versicolor is caused by a yeast infection and can be treated with antifungal medicines , including antifungal creams and antifungal shampoos.
Page last reviewed: 13 March Next review due: 13 March
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