Ihottumaläiskät

Ihottumaläiskät, also known as pityriasis rosea, is a common, self-limiting skin condition that typically affects young adults. It begins with a single, larger, oval-shaped patch called a herald patch, which often appears on the trunk or upper arms. This herald patch can vary in size and may be mistaken for ringworm.

Within one to two weeks after the appearance of the herald patch, a widespread rash develops. This secondary rash consists of numerous smaller, oval-shaped patches that usually follow the lines of cleavage on the back, creating a characteristic "Christmas tree" pattern. The individual patches are typically pink or tan, with fine scaling at the edges. The rash can be itchy, though some individuals experience no itching at all.

The exact cause of pityriasis rosea is unknown, but it is believed to be triggered by a viral infection, possibly a human herpesvirus (HHV-6 or HHV-7). It is not contagious and does not spread from person to person. The condition usually resolves on its own within six to eight weeks, although some cases can last longer. Treatment is generally not required, as the rash disappears spontaneously. For symptomatic relief of itching, over-the-counter antihistamines or topical corticosteroids may be recommended by a healthcare professional.