Editors

AlexanderSalava

Pityriasis Rosea

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.

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

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.

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)

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.

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

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]