Images of Pityriasis Rosea (9)
Pityriasis rosea (PR) is a common, non-cancerous (benign) rash that mostly affects the back, chest, and abdomen. It starts fairly quickly, lasts about 6–8 weeks, and is usually not itchy.
The cause of pityriasis rosea is not known, though it may be due to infection with an unknown virus.
Who's At Risk?
Pityriasis rosea can occur in people of any age, any race, and either sex, but it is most common in teens and young adults (10–40 years old). Pityriasis rosea is uncommon in children younger than 5 years old.
Signs & Symptoms
The most common locations for pityriasis rosea include:
- Upper back
- Upper arms
In an uncommon type of pityriasis rosea, the rash may be concentrated in the armpits and groin or on the face, forearms, and shins.
Pityriasis rosea usually begins with a single patch of pink-to-red, scaly skin, from 2–5 cm in size. This “herald patch” is usually located on the trunk, neck, or upper arms. The herald patch is followed 1–3 weeks later by the development of a widespread rash, with smaller (0.5–2 cm) oval patches of pink-to-red, scaly skin on the trunk and upper arms. The second rash may form a “Christmas tree” pattern on the back.
Children sometimes have an unusual form of pityriasis rosea with lesions on the face, wrists, and legs rather than on the trunk.
Some children report feeling mildly ill (headache, stuffy nose, muscle aches) for 1–2 weeks before the herald patch forms. Additionally, some children have itching with pityriasis rosea. Becoming overheated by exercising or taking a hot shower may increase itching or make the rash more apparent.
Pityriasis rosea is a self-limited condition, meaning that it goes away on its own within 6–8 weeks even without treatment. However, the rash often leaves behind patches of lighter (hypopigmented) or darker (hyperpigmented) skin, which are more obvious in darker-skinned people and may take months to return to normal color.
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The herald patch of pityriasis rosea may be mistaken for ringworm (tinea corporis), but over-the-counter antifungal creams do not improve it. Similarly, the herald patch may look like eczema, but over-the-counter hydrocortisone creams do not affect it. The second, widespread rash of pityriasis rosea will always develop even if the herald patch is treated.
Itching with pityriasis rosea can sometimes be reduced by:
- Oatmeal baths
- Lukewarm (rather than hot) baths and showers
- Antihistamine pills
Other than relieving the itch, there are no self-care measures for pityriasis rosea. Although the rash should go away on its own within 6–8 weeks, see your child’s doctor for evaluation of any widespread rash.
Although most people have the classic form of pityriasis rosea, some individuals develop a form of pityriasis rosea with unusual (atypical) features. These atypical types of pityriasis rosea may be more difficult to diagnose and may require a skin biopsy.
The procedure involves:
- Numbing the skin with an injectable anesthetic.
- Sampling a small piece of skin by using a flexible razor blade, a scalpel, or a tiny cookie cutter (called a “punch biopsy”). If a punch biopsy is taken, a stitch (suture) or two may be placed and will need to be removed 6–14 days later.
- Having the skin sample examined under the microscope by a specially trained physician (dermatopathologist).
In addition, the doctor may want to do blood tests for other medical conditions.
Because pityriasis rosea is benign and self-limited, no treatment is required. However, some people with pityriasis rosea have mild-to-severe itching, and your physician may suggest:
- Moisturizing creams or lotions
- Oatmeal baths
- Topical menthol-phenol lotions
- Topical corticosteroid (cortisone) creams or lotions
- Oral antihistamine pills
- Ultraviolet light treatments
If your child develops a patch of pink, scaly skin that does not respond to over-the-counter antifungal creams or hydrocortisone cream, or if your child develops a widespread rash, see his or her doctor or a dermatologist for an evaluation.
Be prepared to discuss the following with the doctor:
- The course of the rash (when it started, whether or not there was a herald patch, etc).
- What treatments, if any, you have tried.
- Whether or not any friends or relatives have a similar rash.
- Your child’s medication history. (Make sure you know the names of any pills your child has taken within the last month.)
Bolognia, Jean L., ed. Dermatology, pp.158-160. New York: Mosby, 2003.
Freedberg, Irwin M., ed. Fitzpatrick’s Dermatology in General Medicine. 6th ed. pp.445-449. New York: McGraw-Hill, 2003.