What is Pityriasis rosea?
Pityriasis Rosea refers to rash thought to be caused by the Herpes virus type 7
The earliest manifestation of Pityriasis Rosea is a herald patch - an oval patch with scaling on the outside and clearing on the inside. The herald patch is often mistaken for a fungal infection (ringworm).
An interval of a few days follows the herald patch, with no additional rash.
Following this interval, a generalised eruption develops, with crops appearing every two to three days for about 10 days. The eruption is made up small ovals which align themselves in the pattern of a Christmas tree. This pattern is most pronounced on the back but is often evident on the chest and abdomen as well. The upper third of the limbs are frequently involved. The rash is unusual on the face and hands.
The rash of Pityriasis Rosea lasts about 6 - 8 weeks and usually disappears without trace. In pigmented individuals, some degree of darkening may be seen where the rash was present. This fades over time.
What other conditions can look like Pityriasis Rosea?
Ringworm (fungal infection)
Allergic reaction to medicines
Moisturisers with method (eg. Vitasure Skincalming Cream)
Antihistamines for the itch
For severe cases, systemic steroids may be administered
Narrow band UVB light helps in the resolution of the rash (see below).
Pityriasis Rosea treated with narrow band UVB. © Dr N Raboobee
17 year old male with Pityriasis rosea (PR) treated at Westville Hospital with narrow band UVB 3 times a week for two weeks (total of 7 treatments - with a dramatic result.
This treatment is being offered following a publication by Jairath and coauthors in the Indian Dermatology Online Journal in which 100 patients with PR were divided into two groups. One received NBUVB and the other no treatment. The results were then compared in the two groups.
The authors concluded that narrow band UVB markedly improved the severity of symptoms in PR.
To read the full article, please click here.