Pityriasis Rosea

Question 1

What is pityriasis rosea?

Answer 1

Acute, self-limiting rash that tends to affect young adults.

Question 2

What is the cause of pityriasis rosea?

Answer 2

Herpes hominis virus 7 (HHV-7) may play a role.

Question 3

What are the features of pityriasis rosea?

Answer 3

Some may give history of recent viral infection

Herald patch (usually trunk)

Erythmatous, oval, scaly patches following characteristic distribution with the longitudinal diameters of the oval lesions running parallel to the line of Langer (fir-tree appearance)

Question 4

What is the management of Pityriasis rosea?

Answer 4

Self-limiting - usually disappears after 6-12 weeks.

Question 5

What condition can be mistaken for Pityriasis rosea?

Answer 5

Guttate psoriasis

Question 6

How does the prodrome for Pityriasis rosea differ from Guttate psoriasis?

Answer 6

PR - May have RT infection but uncommon

GP - Preceded by a streptocococcal sore throat 2-4 weeks.

Question 7

How does the appearance of Pityriasis rosea differ from Guttate psoriasis?

Answer 7

PR - Herald patch followed 1-2 weeks later by fir-tree rash.

GP - ‘Tear drop’, scaly papules on the trunk and limbs

Question 8

How does the treatment of Pityriasis rosea differ from Guttate psoriasis?

Answer 8

PR - Self-limiting, resolves after around 6 weeks.

GP - Most cases resolve within 2-3 months, topical agents as per psoriasis. UVB phototherapy.