Pityriasis rosea

Pityriasis rosea

1. Pityriasis rosea Done by.. Dr.Manar AlSanaa Ali

2. An acute, self-limited, exanthematous skin disease characterized by the appearance of slightly inflammatory, oval, papulosquamous lesions on the trunk and proximal areas of the extremities. Incidence is 170 cases per 100,000 persons per year.

3. Etiology A viral etiology for pityriasis rosea (PR) has been hypothesized based upon the following observations: ●PR is sometimes preceded by a prodrome . ●It occasionally occurs in small case clusters. ●It has not been shown to be associated with bacterial or fungal organisms. reinforced by the finding of viral-like particles in PR biopsy specimens examined with the electron microscope. The most common viruses linked are human herpesvirus-6 and - 7.

4. Clinical Presentation Diagnosis of pityriasis rosea is based on clinical and physical examination findings.

5. S tarts with a herald patch on the trunk in up to 90% of cases. The patch is erythematous with slightly elevated scaling borders and a lighter depressed center. It can measure 3 cm or more in diameter and may be the only skin manifestation for approximately two weeks.

6. Prodromal symptoms (e.g., general malaise, fatigue, nausea, headaches, joint pain, enlarged lymph nodes, fever, sore throat) present before or during the course of the rash in 69% of patients.

7. The generalized rash, also known as the secondary eruption, presents on the trunk along the Langer lines. M ay extend to the upper arms and upper thighs. These lesions are smaller than the herald patch and can continue to appear up to six weeks after the initial eruption.

8. A rash on the back may have a “Christmas tree” pattern.

9. A rash on the upper chest may have a v-shaped pattern. The mean duration of the rash is 45 days; however, it can last up to 12 weeks. Moderate to severe pruritus occurs in 50% of patients.

10. RELAPSES Relapse rate low, between 1.8% and 3.7 %. Typically occurs within five to 18 months of the initial episode. Lacks a herald patch. lesions usually smaller or fewer than in the initial episode.

11. SPECIAL POPULATIONS Children: presents similarly to that in adults . Pruritus more often. Black children have more facial (30%) and scalp involvement (8%), and postinflammatory pigmentary changes (62 %). Pregnancy: more susceptible to pityriasis rosea because of their altered immune response. Increase in overall rate of spontaneous abortion. The rate may reach to 57% in patients who developed pityriasis rosea in the first 15 weeks of gestation .

12. Differential Diagnosis Lichen planus 1- to 10-mm, sharply defined, flat-topped violaceous papules typically on wrists, lumbar region, shins, scalp, glans penis, and mouth; lesions may be asymptomatic

13. Tinea corporis Scaling, sharply marginated plaques of various sizes with or without pustules or vesicles along the margins. lesions present with peripheral enlargement and central clearing, producing an annular configuration with concentric rings or arcuate lesions.

14. Tinea versicolor presents with hypopigmented or hyperpigmented macules that are most commonly located on the neck and trunk. Unlike in PR, erythema is absent or minimal. The scale in tinea versicolor is fine, and lesions lack the peripheral rim of scale that is often seen in PR.

15. Nummular eczema presents with intensely pruritic, coin-shaped plaques that may range in size from 2 to 10 cm. Grouped small vesicles and papules 4 to 5 cm in diameter; round or coin-shaped lesions with an erythematous base and distinct borders. Involvement of the extremities is more common. Serous exudate may be visible in acute lesions.

16. Guttate psoriasis is a variant of psoriasis that most frequently affects children and young adults . Small, erythematous, scaly plaques are distributed primarily on the trunk. The scale tends to be coarser than the scale associated with PR , a herald patch does not precede the eruption. frequently is associated with a preceding streptococcal infection.

17. Seborrheic dermatitis Orange-red or gray-white skin with greasy or white dry scaling macules, papules, or patches ; diffuse scalp involvement with marked scaling; worsens in winter because of dry conditions ; pruritus increases with perspiration

18. Pityriasis lichenoides chronica Red-brown papules with central mica-like scales randomly arranged on trunk and proximal extremities with chronic, relapsing course hypo- or hyperpigmentation may be present after lesions resolve. may be asymptomatic or pruritic, and spontaneously regress over the course of weeks to months . Most commonly occurs in children and young adults. The disorder may persist for years.

19. Pityriasis rosea –like eruption associated with medications Adalimumab ( Humira ) Allopurinol Asenapine ( Saphris ) Arsenic compounds Atenolol Barbiturates Bismuth Bupropion (Wellbutrin ) Captopril Clonidine Clozapine ( Clozaril ) Ergotamine Etanercept (Enbrel ) Hepatitis B vaccine Imatinib ( Gleevec ) Influenza (H1N1) vaccine Interferon alfa-2a Isotretinoin Ketotifen ( Zaditor ) Lamotrigine ( Lamictal ) Lisinopril Nortriptyline ( Pamelor ) Omeprazole (Prilosec ) Pneumococcal polysaccharide vaccine ( Pneumovax ) Rituximab ( Rituxan ) Smallpox vaccine Terbinafine (Lamisil ) Yellow fever vaccine

20. Treatment Patient/parent education     information about clinical course, infectivity, and relapse. Reassure typically spontaneously resolves within two to three months, a low likelihood for transmission, and does not recur in most patients . Pruritus: topical corticosteroids in the medium potency. Topical antipruritic lotions. oral antihistamines.

21. Severe cases Acyclovir: a few small trials suggest that may accelerate resolution of the clinical manifestations. 400 to 800 mg, five times per day for one week . Improvement is expected within one to two weeks.

22. Phototherapy : T wo small studies found improvements in severity and symptoms in patients with pityriasis rosea who received ultraviolet B phototherapy multiple times per week for up to four weeks . Macrolid : The efficacy of oral erythromycin for PR is uncertain based upon conflicting efficacy data for erythromycin and the failure of randomized trials of other macrolides to find benefit in PR.