Pityriasis rosea refers to a rosy rash most commonly seen in young adults. Although it is unsightly, the rash is is not painful and causes mild to severe itching in only 25 percent of patients. It disappears within eight to 12 weeks without treatment. There is no evidence that quercetin has any benefit in treating this condition. While quercetin may confer various medical benefits, none are related to pityriasis rosea.
Quercetin
Quercetin is a polyphenol found in many fruits and vegetables. The USDA Database for the Flavonoid Content of Selected Foods states that there are 3.11 mg quercetin in 100 g fresh blueberries, 1.30 mg in 100 mg green beans, 2.55 mg in a 100 mg apricot and 4.42 mg in a 100 g apple with skin. The value of these numbers is unclear because there is no recommended daily allowance for quercetin.
Quercetin Benefits
The American Cancer Society talks about quercetin with cautious optimism. It notes that while early lab results point to anti-inflammatory, antioxidant and antihistamine properties, there is no reliable evidence that any of these benefits can be used to prevent or treat cancer in humans. This attitude applies to using quercetin to treat other disorders as well. As of 2011, the few human studies that have been performed focus on the more general role of flavonoids in the diet, instead of quercetin in particular. Clinical trials are necessary to better define the particular effects of quercetin.
Clinical Presentation
Pityriasis rosea often begins with what is called a "herald patch," which appears as a large 2 to 10 cm lesion on the trunk. This lesion is oval, slightly raised and has a white scaly ring around it called a collarette. Smaller lesions follow, most often on the patient's front and back. These are the same color and shape as the herald patch, with the same collarette.
Treatment
Unless the patient complains about itching, pityriasis rosea often goes untreated. If itching is a problem, doctors may suggest calamine lotion, oral antihistamines, and topical or oral steroids such as prednisone. Quercetin is neither a conventional nor a complementary treatment for this condition. According to a January 2004 article in the journal "American Family Physician," if the rash does not go away after three months, a doctor should reconsider the diagnosis.
