Pityriasis rosea

Question 1

What is pityriasis rosea (PR)?

Answer 1

• It is a viral rash characterised by a hearald patch followed by similar, smaller red patches that are locaed mainly on the chest and back
• It lasts 6-12 weeks

Question 2

Who gets it?

Answer 2

• It often affects teenagers nd young adults
• Anybody can get it

Question 3

What are the clinical features of PR?

Answer 3

• The rash sometimes follows a few days of URTI
• The herald patch is a single palque that appears 1-20 days before the generalised rash. It is an oval pin to red rash
• Secondary rash is characterised by more scaly patches or palques on the chest and back.
• they are smaller than the herald patch
• It has a fir tree appearance as it follows the cleavage (Langers lines)
• It spares the face, scalp, palms or soles
• It can sometimes be atypical in morphology with unusual distribution, only a hearald patch and involvement of the mucosal sites
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Question 4

What causes PR?

Answer 4

• It is likely caused by reactivation of the herpes virus 6 and 7
• It can also be drug induced with medications such as ACEI, HCT, metronidazole, atypical psychotics and terbinafine

Question 5

How long does it last?

Answer 5

• Usually lasts 6-12 weeks
• Eventually the skin returns to normal

Question 6

Does it cause any complications?

Answer 6

• It can cause miscarriage, premature delivery and perinatal problems in pregnancy

Question 7

How is it diagnosed?

Answer 7

• It is a clinical diagnosis
• Rarely biopsy is needed

Question 8

How to treat PR?

Answer 8

• Bathe or shower with plain water and soap substitute
• Moisturise dry skin
• Expose skin to sunlight cautiously
• A 2 week course of erythromycin or 7 day course of acyclovir has been reported to help
• topical steroids help to reduce itch
• Extensive or persistent cases can be treated with phototherapy