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AlexanderSalava

Pityriasis Rosea

Essentials

  • Pityriasis rosea is a self-limiting exanthematous disease.
  • Diagnosis is based on clinical presentation and the two-phase course of the disease.
  • Treatment is symptomatic.

Aetiology

  • In many cases caused by HHV6/HHV7 viral infection or reactivation
  • Triggering factors may include some other viral infections, drugs or vaccinations.

Course of the disease

  • The typical two-phase course is diagnostic.
  • A solitary initial patch “heralds" the eruption (picture 1), often on the trunk or the chest.
    • A well-demarcated, erythematous, oval lesion which later on develops a collarette of fine scale inside the border (pictures 2 3)
    • Occasionally the herald patch is absent.
  • A few weeks after the herald patch, several smaller (0.5-3 cm in diameter), oval-shaped, salmon-pink patches, the longitudinal axis of which mainly follow the tension lines (e.g. rib-lines), appear in a pox-like fashion on the trunk and proximal extremities (pictures 4 5).
  • Mild pruritus is sometimes present. The skin lesions can be irritated by external factors (e.g. washing, sauna etc.)
  • The condition is not contagious, and it may occur more frequently in spring and autumn.

Differential diagnosis

  • Drug eruptions (picture 6) may resemble widespread pityriasis rosea.
  • Guttate psoriasis Psoriasis is often associated with genetic predisposition, and scaling is generally more prominent (picture 7). It is often triggered by streptococcal tonsillitis.
  • Tinea versicolor (pictures 8 9) is lighter coloured and develops more slowly. The patches are usually not reddish and the rash is not preceded by a herald patch.
  • Tinea corporis may mimic the herald patch (picture 10); in some cases fungal samples are indicated (for microscopy and culture).
  • Secondary syphilis (picture 11) Syphilis is rare in industrialised countries. When clinically suspected, it can be excluded with an antibody assay (serum Treponema pallidum antibodies)

Treatment

  • In most cases, all that is needed is reassurance that the prognosis is good and the lesions are benign.
  • Usually resolves spontaneously within 6-8 weeks, but may persist longer. Recurrence is not common.
  • If required, pruritus may be alleviated with moderately potent to potent topical glucocorticoids or oral antihistamines.
  • The avoidance of exposure to irritant agents (e.g. sauna) may be beneficial.
  • In severe or prolonged cases aciclovir 400 mg 3 times daily Interventions for Pityriasis Rosea for a period of one week.

Specialist consultation

  • Prolonged disease may often require the intervention of a dermatologist. UVB light treatment, for example, may be used to manage the condition.

    References

    • Chuh A, Zawar V, Sciallis G, et al. A position statement on the management of patients with pityriasis rosea. J Eur Acad Dermatol Venereol 2016;30(10):1670-1681. [PubMed].
    • Monastirli A, Pasmatzi E, Badavanis G, et al. Gestational Pityriasis Rosea: Suggestions for Approaching Affected Pregnant Women. Acta Dermatovenerol Croat 2016;24(4):312-313. [PubMed]
    • Eisman S, Sinclair R. Pityriasis rosea. BMJ 2015;351:h5233. [PubMed]
    • Drago F, Ciccarese G, Rebora A, et al. Pityriasis rosea and pityriasis rosea-like eruption: can they be distinguished? J Dermatol 2014;41(9):864-5. [PubMed]
    • Drago F, Broccolo F, Agnoletti A, et al. Pityriasis rosea and pityriasis rosea-like eruptions. J Am Acad Dermatol 2014;70(1):196. [PubMed]