Pityriasis Rosea: common skin disease

Pityriasis rosea - This common skin disease causes patches on the skin. Your dermatologist may call the large patch a mother patch. The smaller patches are daughter patches.

Pityriasis rosea (pit-uh-rahy-uh-sis row-zee-ah) is a common skin disease that causes a rash. This rash usually disappears on its own without treatment. You can expect to see the rash for about 6 to 8 weeks. Sometimes the rash lasts much longer.

Pityriasis is a common skin problem that causes a rash. Although it can occur at any age, it is seen most often in those between the ages of 10 and 35.

Pityriasis rosea is usually harmless. But it can cause serious problems in pregnant women.

What are the symptoms?
Pityriasis rosea causes a rash.

• The rash often begins with a single, round or oval, pink patch that is scaly with a raised border (herald patch). The size of the patch ranges from 2 cm (0.8 in.) to 10 cm (3.9 in.). The larger patches are more common. 
• Days to weeks later, salmon-colored, 1 cm (0.4 in.) to 2 cm (0.8 in.) oval patches appear in batches on the abdomen, chest, back, arms, and legs. Patches sometimes spread to the neck but rarely to the face.
• Patches on the back are often vertical and angled to form a "Christmas tree" or "fir tree" appearance.
• The rash does not cause itching in 25% of people who have pityriasis rosea. For 50% of people, the itch is mild to moderate. And for 25% of people, the itch is severe.1
• The rash usually lasts 6 to 8 weeks, but it can last up to several months.

Causes

The exact cause of pityriasis rosea is unclear, although there is some evidence that the rash may be triggered by a viral infection, particularly by certain strains of the herpes virus. Pityriasis rosea, however, isn't believed to be contagious.

Complications

Complications of pityriasis rosea aren't likely, but if they do occur, they may include:

• Severe itching
• Lasting brown spots after the rash has healed, on dark skin