Pityriasis Rosea
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BMJ 2015;351:h5233 doi: 10.1136/bmj.h5233 (Published 29 October 2015) Page 1 of 6 Practice PRACTICE PRACTICE POINTER Pityriasis rosea Samantha Eisman consultant dermatologist, Rodney Sinclair professor in dermatology Sinclair Dermatology, Melbourne, VIC, 3002, Australia Pityriasis rosea is an acute exanthem that may cause patients great anxiety but is self limiting and resolves within one to three How does pityriasis rosea present? months.1 It is a distinctive erythematous oval scaly eruption of Pityriasis rosea begins in 40-76% of patients with a single herald the trunk and limbs, with minimal constitutional symptoms. patch—an asymptomatic thin oval scaly plaque often on the What causes pityriasis rosea? trunk (fig 1⇓).7 Multiple herald patches may also occur.8 The patch is usually well demarcated, 2-4 cm in diameter, The cause of pityriasis rosea is uncertain but epidemiological erythematous, salmon coloured, or hyperpigmented. A fine (seasonal variation and clustering in communities) and clinical collarette of scale is attached to the periphery of the plaque with features suggest an infective agent. Light and electron its free edge extending internally. Within days to three weeks microscopy findings suggest infection with human herpesviruses 2 the second phase begins—the appearance of numerous smaller 6 and 7 (HHV-6/7). These viral antigens have been detected lesions, which are similar in configuration but occur along the in skin lesions by immunohistochemistry and their DNA has lines of cleavage of the trunk (Christmas tree pattern; figs 2⇓ been isolated from non-lesional skin, peripheral blood 3 and 3⇓). The rash typically lasts five weeks; it resolves within mononuclear cells, serum, and saliva samples. HHV-6 and eight weeks in 80% of patients but can last for five months.8 HHV-7 may also interact with each other, explaining recurrences After recovery, the affected skin may be hyperpigmented or and atypical presentations. hypopigmented but will not scar. Drugs and pityriasis rosea Not all patients present with typical morphology and distribution; 20% present with atypical disease,9 in which A pityriasis rosea-like eruption has been attributed to several morphology, size, distribution, number, site, severity, and drugs (box 1), mostly in single case reports, as identified in our disease course are unusual. The more common atypical variants scan of the literature. In the drug induced form there is no herald include unilateral, inverse, lichenoid, vesicular, papular, patch, individual lesions tend to be violet-red in colour, pruritus purpuric, erythema multiforme-like, and urticarial types (fig is more severe, and eosinophilia may be present. It has been 4⇓).9 speculated that drugs can trigger HHV-6 or HHV-7. However Constitutional symptoms are usually absent but a recent case a small series of 12 cases found HHV-6 DNA in the plasma of series of 52 patients found prodromal symptoms (fever, one of 10 patients only, and all patients recovered within two 4 headache, arthralgia, cough, vomiting, or lymphadenopathy) in weeks of discontinuing the drug. 59.6%.10 Pruritus is variable in intensity and frequency and has If the rash lasts longer than two months consider whether been reported to affect 50% of patients.5 Topical treatments of medication may be responsible (box 1). If a drug is suspected all forms have been reported to exacerbate the pruritus.8 but is medically indicated, refer the patient to a dermatologist Relapse rates of 1.8-3.7% have been reported, but these are and, if appropriate, a relevant specialist (such as a neurologist probably underestimates.8 Multiple recurrences are about antiepileptic treatment) to help with decisions about uncommon—three or more episodes have been reported in only whether to stop the drug. eight patients, and the maximum number reported is five.11 Who gets pityriasis rosea? How do we diagnose pityriasis rosea? Pityriasis rosea mainly affects adolescents and young adults 5 Pityriasis rosea can be difficult to diagnose, especially at the aged 10-35 years. A meta-analysis showed an incidence of onset of symptoms. Other non-specific viral exanthems can be 0.68/100 dermatology patients in specialised settings and 6 mistaken for pityriasis rosea and the differential diagnosis is prevalence has been estimated at 1.3% people in the community. wide (table⇓). No non- invasive tests can confirm the diagnosis. Correspondence to: S Eisman [email protected] For personal use only: See rights and reprints http://www.bmj.com/permissions Subscribe: http://www.bmj.com/subscribe BMJ 2015;351:h5233 doi: 10.1136/bmj.h5233 (Published 29 October 2015) Page 2 of 6 PRACTICE Box 1: Medications reported to be implicated in pityriasis rosea-like eruptions (based on our scan of the literature) • Antibiotics/antifungals: metronidazole, pristinamycin, terbinafine • Antidepressants/anxiolytics: nortriptyline, barbiturates, bupropion • Antiepileptic: lamotrigine • Antihypertensives: angiotensin converting enzyme inhibitors (captopril), clonidine, hydrochlorothiazide, atenolol • Antipsychotics: asenapine, clozapine • Biological agents: adalimumab, rituximab • Metals: arsenic, bismuth, gold • Vaccines: hepatitis B, H1N1 influenza, yellow fever, BCG, diphtheria, smallpox, pneumococcus, human papillomavirus • Others: isotretinoin, non-steroidal anti-inflammatory drugs, omeprazole A Cochrane review noted that the diagnosis is clinical and that clinic may be necessary. Although evidence is contradictory, various investigators have used different inclusion and exclusion many dermatologists will consider a monitored trial of ultraviolet criteria in their studies, making systematic reviews and B phototherapy for more aggressive eruptions. meta-analyses difficult.5 For this reason, diagnostic criteria have 12 Patient distress or request for referral to a dermatologist should been proposed for typical and atypical pityriasis rosea (box 2). also be taken into account. Their reliability and applicability in all ethnic groups is as yet uncertain. Methods Skin biopsy is not advocated in typical pityriasis rosea; however, histological examination shows non-specific but similar changes We undertook a literature review using the search term in the herald patch and secondary lesions.10 “pityriasis rosea”. We searched Medline, PubMed, and the Cochrane Library. Because the diagnosis is clinical and Pityriasis rosea in children and pregnancy investigators have adopted different inclusion and exclusion criteria in their studies, meta-analysis of previous reports and Reports suggest that 6-10.5% of patients with pityriasis rosea studies is difficult and overall quality of evidence is weak. are under 10 years of age. Children may present with papular Where possible, randomised double blind placebo controlled lesions (33%), and in those with darker skin, residual studies were reviewed; however, owing to their paucity, case hyperpigmentation (48%) may persist.8 States of studies and case reports were also included but were referred immunosuppression can favour reactivation of HHV-6 or to as such in the text. HHV-7. Because the immune response is altered during pregnancy, there is a risk of viral reactivation. A series of 61 Contributors: All authors helped draft the article and have approved the patients found an increased rate of miscarriage in women who final version to be published. SE is guarantor. develop pityriasis rosea in the first 15 weeks’ gestation, so closer Competing interests: We have read and understood BMJ policy on 13 follow-up of these women is recommended. declaration of interests and declare: nil relevant. Provenance and peer review: Commissioned; externally peer reviewed. How can we treat it? Patient consent for fig 2 obtained. Explain to patients that pityriasis rosea is a self limiting 1 Chuh AA, Chan HH. Effect on quality of life in patients with pityriasis rosea: is it associated condition that is not contagious and usually resolves within one with rash severity? Int J Dermatol 2005;44:372-7. to three months. Treatment is usually symptomatic, and there 2 Chuh AA, Chiu SS, Peiris JS. Human herpesvirus 6 and 7 DNA in peripheral blood is currently no good evidence for one specific treatment. A 2007 leucocytes and plasma in patients with pityriasis rosea by polymerase chain reaction: a prospective case control study. Acta Derm Venereol 2001;81:289-90. Cochrane review retrieved four trials (three randomised 3 Watanabe T, Kawamura T, Jacob SE, et al. Pityriasis rosea is associated with systemic controlled trials and one partially randomised controlled trial) active infection with both human herpesvirus-7 and human herpesvirus-6. J Invest Dermatol 2002;119:793-7. and found no adequate evidence for or against the effectiveness 4 Drago F, Broccolo F, Agnoletti A, et al. Pityriasis rosea and pityriasis rosea-like eruptions. of erythromycin, systemic corticosteroids, systemic J Am Acad Dermatol 2014;70:196. 6 5 Chuh AA, Dofitas BL, Comisel GG, et al. Interventions for pityriasis rosea. Cochrane antihistamine, and intravenous glycyrrhizin. It recommended Database Syst Rev 2007;2:CD005068. further randomised control trials be conducted. Various other 6 Chuh AA, Zawar V, Law M, et al. Gianotti-Crosti syndrome, pityriasis rosea, asymmetrical periflexural exanthem, unilateral mediothoracic exanthem, eruptive pseudoangiomatosis, treatment modalities have been tried without evidence of and papular-purpuric gloves and socks syndrome: a brief review and arguments for effectiveness including natural sunlight, ultraviolet phototherapy,