Pityriasis rosea
Pityriasis rosea (also known as pityriasis rosea Gibert[1]) is a skin rash. It is non-dangerous but may inflict substantial discomfort on some people.[2] Classically, it begins with a single "herald patch" lesion, followed in 1 or 2 weeks by a generalized body rash lasting about 6 weeks.[3][4][5]
Signs and symptoms
The symptoms of this condition include:
- An upper respiratory tract infection may precede all other symptoms in as many as 69% of patients[6]
- A single, 2- to 10-cm oval red "herald" patch appears, classically on the abdomen.[7][5] Occasionally, the "herald" patch may occur in a 'hidden' position (in the armpit, for example) and not be noticed immediately. The "herald" patch may also appear as a cluster of smaller oval spots, and be mistaken for acne. Rarely, it does not become present at all.[7]
- 7-14 days after the herald patch, large patches of pink or red, flaky, oval-shaped rash appear on the torso.[7] In 6% of cases an inverse distribution may occur, with rash mostly on the extremities.[8] The more numerous oval patches generally spread widely across the chest first, following the rib-line in a characteristic "christmas-tree" distribution.[7] Small, circular patches may appear on the back and neck several days later. It is unusual for lesions to form on the face, but they may appear on the cheeks or at the hairline.
- About one-in-four people with PR suffer from mild to severe symptomatic itching. (Moderate itching due to skin over-dryness is much more common, especially if soap is used to cleanse the affected areas.) The itching is often non-specific, and worsens if scratched. This tends to fade as the rash develops and does not usually last through the entire course of the disease.[7]
- The rash may be accompanied by low-grade fever, headache, nausea and fatigue. Over-the-counter medications can help manage these.[7]
Causes
The cause of pityriasis rosea is not certain, but its clinical presentation and immunologic reactions suggest a viral infection as a cause.[9][10] Also, HHV-7 is frequently found in healthy individuals, so its etiologic role is controversial.[9]
Diagnosis
Experienced practitioners may make the diagnosis clinically.[5] If the diagnosis is in doubt, tests may be performed to rule out similar conditions such as ringworm, guttate psoriasis, nummular or discoid eczema, drug eruptions, other viral exanthems,[5] and especially secondary syphilis.[11] A biopsy of the lesions will show extravasated erythrocytes within dermal papillae and dyskeratotic cells within the dermis.[5]
Treatment
No treatment is usually required.
Oral antihistamines or topical steroids may be used to decrease itching.[5] Steroids do provide relief from itching, and improve the appearance of the rash, but they also cause the new skin that forms (after the rash subsides) to take longer to match the surrounding skin color. While no scarring has been found to be associated with the rash, itching and scratching should be avoided. It's possible that scratching can make itching worse and an itch-scratch cycle may develop with regular scratching (that is, you itch more because you scratch, so you scratch more because you itch, and so on). Irritants such as soaps with fragrances, hot water, wool, and synthetic fabrics should be avoided; a soap containing moisturizers (such as goat's milk) may be used, however, and any generic moisturizer can help to manage over-dryness. Calamine lotion may be soothing to the skin and reduce itching. Emulsifiers should be used instead of soaps, as emulsifiers are gentler on the skin and include cleansers, eliminating the need for soap.
Direct sunlight makes the lesions resolve more quickly.[5] According to this principle, medical treatment with ultraviolet light has been used to hasten resolution,[12] though studies disagree whether it decreases itching[12] or not.[13] UV therapy is most beneficial in the first week of the eruption.[12]
Prognosis
In most patients, the condition lasts only a matter of weeks; in some cases it can last longer (up to six months). The disease resolves completely without long-term effects. Two percent of patients have recurrence.[14][15]
Epidemiology
The overall prevalence of PR in the United States has been estimated to be 0.13% in men and 0.14% in women. It most commonly occurs between the ages of 10 and 35.[5] It is more common in spring.[5]
PR is not viewed as contagious,[16][2] though there have been reports of small epidemics in fraternity houses and military bases, schools and gyms.[5]
See also
References
- ^ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN 1-4160-2999-0.
- ^ a b "Pityriasis rosea". American Osteopathic College of Dermatology. http://www.aocd.org/skin/dermatologic_diseases/pityriasis_rosea.html. Retrieved 26 Jan 2010.
- ^ Freedberg; et al (2003). Fitzpatrick's Dermatology in General Medicine (6th ed.). McGraw-Hill. p. 445. ISBN 0071380760
- ^ James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology (10th ed.). Saunders. pp. 208–9. ISBN 0721629210.
- ^ a b c d e f g h i j Habif, Thomas P (2004). Clinical Dermatology: A Clinical Guide to Diagnosis and Therapy (4th ed.). Mosby. pp. 246–8. ISBN 0-323-01319-8
- ^ Sharma, P (2000). J Am Acad Dermatol 42 (2 pt 1): 241.
- ^ a b c d e f "Pityriasis rosea". American Academy of Dermatology. 2000, 2003. http://www.aad.org/public/publications/pamphlets/common_pityriasis.html. Retrieved 2009-06-04.
- ^ Tay, Y; Goh, C (1999). "One-year review of pityriasis rosea at the National Skin Centre, Singapore". Ann Acad Med Singapore 28 (6).
- ^ a b Medscape > Pityriasis Rosea Author: Robert A Allen, MD; Chief Editor: Dirk M Elston, MD. Updated: Feb 13, 2009
- ^ Cynthia M. Magro; A. Neil Crowson; Martin C. Mihm (2007). The Cutaneous Lymphoid Proliferations: A Comprehensive Textbook of Lymphocytic Infiltrates of the Skin. John Wiley and Sons. pp. 36–. ISBN 9780471695981. http://books.google.com/books?id=ueYXEbM8AE8C&pg=PA36. Retrieved 10 November 2010.
- ^ Horn T, Kazakis A (1987). "Pityriasis rosea and the need for a serologic test for syphilis". Cutis 39 (1): 81–2. PMID 3802914.
- ^ a b c Arndt, KA; Paul, BS; Stern, RS; Parrish, JA (1983). "Treatment of pityriasis rosea with UV radiation". Arch Dermatol 119 (5): 381–2. doi:10.1001/archderm.119.5.381. PMID 6847217.
- ^ Leenutaphong V, Jiamton S (1995). "UVB phototherapy for pityriasis rosea: a bilateral compatison study". J Am Acad Dermatol 33 (6): 996–9. doi:10.1016/0190-9622(95)90293-7. PMID 7490372.
- ^ Kempf, W; et al, V; Kleinhans, M; Burg, G; Panizzon, RG; Campadelli-Fiume, G; Nestle, FO (1999). "Pityriasis rosea is not associated with Human herpesvirus 7". Arch Dermatol 135 (9): 1070–2. doi:10.1001/archderm.135.9.1070. PMID 10490111.
- ^ Chuang, T-Y; et al (1982). "Pityriasis rosea in Rochester, Minnesota, 1969 to 1978: a 10-year epidemiologic study". J Am Acad Dermatol 7: 80.
- ^ "Pityriasis rosea". DERMAdoctor.com. http://www.dermadoctor.com/article_Pityriasis-Rosea_60.html. Retrieved 26 Jan 2010.
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