Pityriasis rosea
Pityriasis rosea is a skin disorder characterized by a distinct rash, primarily affecting children and young adults, especially females. The condition often begins with a single, larger lesion known as the herald or mother patch, which is typically scaly, pink, and slightly raised. This patch is followed by the emergence of smaller, oval lesions on the trunk, which can create a pattern resembling a Christmas tree. Symptoms may include mild itchiness and occasional fatigue, but the rash generally resolves on its own within four to six weeks without specific treatment. The exact cause remains unclear, though it is believed to be linked to viral infections. While pityriasis rosea is not considered highly contagious, it often appears in clusters among close contacts, particularly in the spring and fall. Treatment focuses on alleviating symptoms, and options may include antihistamines, calamine lotion, or topical steroids if itching is severe. It is important to differentiate pityriasis rosea from other skin conditions such as ringworm and to consider a blood test for syphilis for accurate diagnosis.
Pityriasis rosea
ANATOMY OR SYSTEM AFFECTED: Back, chest, skin
DEFINITION: A skin disorder that manifests with a characteristic rash
CAUSES: Unknown; possibly exposures to viruses
SYMPTOMS: Herald or mother patch, smaller scaly pink lesions on trunk; usually itchy
DURATION: Four to six weeks
TREATMENTS: Self-resolving; alleviation of symptoms may include antihistamines, calamine lotion, steroids, ultraviolet B radiation
Causes and Symptoms
Pityriasis rosea is primarily a skin disease of children and young adults, with females being more commonly affected than males. The initial is a characteristic eruption seen on the called the herald or mother patch, as it signals the onset of lesions to come. This is a scaly pink which is around one to two centimeters in diameter, slightly raised above the surface, with central salmon-colored wrinkles. This lesion should be differentiated from that of and ringworm.
The herald patch is followed in about two weeks by a crop of similar but smaller lesions all over the trunk. The pink scaly oval papules are distributed along the skin tension lines in the trunk and result in a so-called Christmas tree distribution. The lesions may be mild to moderately pruritic (itchy) and will resolve spontaneously in four to six weeks, without any specific treatment. Other symptoms may involve mild aches and fatigue.
The exact cause of this exanthem (eruptive disease) is not known, but it is believed to result from exposure to various viruses. Most patients appear to have a positive recent history of or an upper respiratory tract infection. The eruption typically appears in spring and fall and appears to cluster among close contacts; however, it is not believed to be highly contagious.
Treatment and Therapy
There is no specific treatment for pityriasis rosea, and usually none is required, as the disease is self-limited and resolves without treatment in four to six weeks. Pruritus is usually mild and can be treated with and calamine lotion. If is severe, then topical and a short, tapered dose of steroids may be administered. Ultraviolet B (UVB) radiation is another treatment option. Patients are also advised to avoid hot showers and strenuous activity, as sweat and water appear to exacerbate the rash.
Perspective and Prospects
The term pityriasis is derived from the Greek pityron, meaning “scales.” The term, initially applied to include all those skin disorders that were characterized by fine scales, is presently used only with modifiers such as rosea, alba, or versicolor. Rosea means “pink,” and therefore pityriasis rosea describes pink-colored, fine, scaly lesions.
It is important clinically to distinguish the herald patch from other skin conditions. Therefore, a blood test for syphilis should be included for differential diagnosis. Also, ringworm, which requires treatment with antifungal agents, should be ruled out.
About 3 percent of the patients with pityriasis rosea experience recurrences, and no systemic manifestations have been demonstrated.
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