Pityriasis rosea starts with a single herald patch somewhere on the body followed 1-2 weeks later with a generalized eruption of itchy scaly skin rash in a typical distribution over the whole body. Pityriasis rosea has a self limiting course and no active treatment is usually required.
Pityriasis rosea is seen in the age group of 10 -45 years, though it can occur in younger children and old persons. Pityriasis rosea commonly occurs in the spring and the fall.
Cause of Pityriasis Rosea
Herpes virus type 7 is suspected as the cause for pityriasis rosea. The herald patch could be the initial skin reaction caused by the virus. Later generalized eruption is thought to be a hypersensitivity reaction to the viral antigen, though no proof has yet been elucidated.
Signs and Symptoms of Pityriasis Rosea
- Herald patch. A single herald patch precedes the body rashes by 10- 14 days. The herald patch, also known as the mother patch, is present in 80% of cases. It is round or oval in shape, slightly raised patch, 2-5 cm in size, salmon red or grayish in color, with a fine scale in the periphery of the patch.
- Skin Rashes. These start as small scaly patches and gradually enlarge to form the typical round or oval patches with a collaret of scales in the periphery. The color is similar to the herald patch. The scales in the periphery are attached towards the outside and open towards the center. This characteristic is a diagnostic feature of pityriasis rosea. Another characteristic is the typical fir tree or Christmas tree distribution of the rashes on the body along the lines of cleavage. These rashes are usually confined to the trunk and proximal limbs.
- Itching. Itchy skin rashes are present in 75% of cases of pityriasis rosea. Itching is severe in 25% of cases and mild or negligent in 50% cases.
- Even without treatment, spontaneous remission occurs in pityriasis rosea in 4-14 weeks.
Clinical Variants of Pityriasis Rosea
- Inverse pityriasis rosea. The skin rashes are on the face and distal limbs, which are the areas spared in classical pityriasis rosea.
- Papular pityriasis rosea. Small bumps more than scaly patches.
- Vesicular pityriasis rosea. Minute vesicles predominant
- Purpuric pityriasis rosea. Salmon red spots and rashes.
- Erythema multiforme like pityriasis rosea. Central vesicle with surrounding red rash.
- Eczematous pityriasis rosea. The skin becomes erythematous and irritated.
Diseases Resembling Pityriasis Rosea
- Ring worm or tinea corporis
- Secondary Syphilis
- Generalized Lichen Planus
- Drug reaction
- Pityriasis versicolor
- Guttate psoriasis
- Viral rashes
Treatment of Pityriasis Rosea
- Oral antihistamines. Benadryl 1 or Cetrizine 10 mg 1 at night will relieve itching.
- Topical emollients or moisturizing lotions are sufficient topically in most cases.
- In severe inflamed pityriasis rosea, topical or oral steroids may be indicated.
- Some cases respond well to Erythromycin 250 mg 4 times daily for 2 weeks.
Though viral origin is suspected, antiviral medications are not effective in pityriasis rosea. This could be because the disease is only a hypersensitivity response of the skin to the viral antigen and not really an infectious disease.
Reference
Disclaimer
The information given in this article is for educational purpose only so that patients are aware of the options available. No diagnosis should be made or treatment undertaken without first consulting your doctor. If you do so, the author or suite101 will not be responsible for any consequences. The images provided are for illustration purpose only.
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