Causes of pityriasis rosea. By Dr Ananya Mandal, MDPityriasis rosea is a common skin condition that affects 0. The condition often occurs in older children and young adults between ages 1. The condition has been described for more than two centuries and has a characteristic rash that begins with a small patch called the “herald patch”. This is followed by spread of a red, scaly, itchy rash to the chest, back, arms and legs. Women are at a slightly higher risk of this condition. Is pityriasis rosea an infection? The exact cause of this condition is still unknown. There are certain factors that lead to the belief that this may be caused by a viral infection. Pityriasis rosea (PR) is a benign. On the back, this eruption. Plantar herald patch in pityriasis rosea. Herald Patch in Pityriasis Rosea. The rash often begins with a herald patch-a single, round-to-oval, pink patch that is scaly with a raised border. Patches on the back are often vertical and angled to form a 'Christmas tree' or. Pityriasis Alba; Ringworm of. Pityriasis rosea; Herald patch in pityriasis. Pityriasis rosea; Herald patch in pityriasis. Patches on the back are often vertical and angled to form a 'Christmas tree' or. Pityriasis Alba; Ringworm of. Pityriasis rosea on human back and front. A herald patch of pityriasis rosea which started before the rest of the lesion and was initially. Pityriasis rosea is a self. Pityriasis is not usually. A 'herald patch' usually. Pityriasis rosea is a. These patches often form a pattern over the back resembling the. The reasons for this belief is that pityriasis rosea tends to occurs in epidemics and affects large groups of persons together in a community especially during spring and autumn seasons. This could mean an infectious agent is responsible for the condition. In addition, recurrence is rare and this means that persons getting the rash may develop long lasting immunity to the infectious agent responsible for the condition. Another significant sign that there could be an infectious agent behind pityriasis rosea is that more than 5. This precedence of rash with general feeling of being unwell (termed prodromal symptoms) is common in cases of other viral infections. The course of the disease is also well defined and similar for most affected persons and follows a pattern much like other viral infections like measles or chicken pox. In addition, some patients also show an increase in B lymphocytes and a decrease in T lymphocytes along with increase in Erythrocyte sedimentation rate (ESR). Lymphocytes are white blood cells that fight against infections so their rise is also significant. In addition, many infections show a rise in the ESR. What may be causing pityriasis rosea? Some studies have suggested that a virus may be causing pityriasis rosea. When seen under an electron microscope viral changes and virus particles have been noticed. However ,blood tests for antibodies against the viruses or special tests like polymerase chain reaction for viruses have not been positive to pinpoint a specific virus causing the condition. Some studies have implicated Human Herpes Virus 6 and 7 in causation of pityriasis rosea. Other infections that need to be considered as causative agents of this condition include Legionella pneumoniae, Chlamydia pneumoniae and Mycoplasma pneumonia. However, these have not been proved. Studies have suggested that some drugs may lead to drug- induced pityriasis rosea. These include: barbiturates (sedatives)bismuthcaptopril (used in high blood pressure)gold (used in rheumatoid arthritis)metronidazole (antibiotic)D- penicillamine (chelating agent used in certain poisonings)isotretinoin (anti- aging skin preparation) Despite these speculations, and occurrence of the rash in more than one person in a household at a time and more than one person in the community at a time, the disease is not contagious and does not spread from one person to another by touching. Reviewed by April Cashin- Garbutt, BA Hons (Cantab)Further Reading.
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