Pityriasis rosea

Initial medallion

1

Details of macules of the secondary eruption, showing fine desquamation, pityriasiform.

D.Wallach, MD - Club dermaweb

D.Wallach, MD - Club dermaweb

D.Wallach, MD - Club dermaweb

14.08.2010 © Club Dermaweb ı http://www.clubdermaweb.com

D.Wallach, MD - Club dermaweb

D.Wallach, MD - Club dermaweb

What needs to be known!

Pityriasis rosea, described by Gibert in 1860, is a frequent dermatosis that is benine, transient and affects mainly young adults. Its etiology is unknown. It is possibly due to a viral infection, but this suggestion is debatable.Pityriasis rosea seems to be more frequent in spring and autumn. Its heals spontaneously without sequelae and only rarely reccurs. There are no known complications.

What needs to be done!

Establish the diagnosis, by a simple clinical examination

Pityrisasis rosea includes two types of lesions:

- The initial medallion, on the trunk and top of one limb. This annular pink plaque of 4 to 6 cm in diameter, is shaped as a ring and is finely squamous.

- A disseminated eruption that appears a few days later. It affects mainly the trunk and tops of the limbs, sometimes the neck and more rarely the face or extremity of the limbs. It consists of small pink macules, that are sometimes finely squamous, sometimes annular.

There is no pruritus (or very moderate pruritus), and no other manifestation and no fever.

It must not be mistaken for a mycosis

When the medallion and the secondary eruption are present, the diagnosis is easy. Atypical forms can require discussion:

- In the case of an isolated medallion, dermatophytosis;- In the case of an infiltrated secondary eruption, with no

initially identifiable medallion, secondary syphilis; - Sometimes eczematides, psoriasis or small plaque

psoriasis.

In practice, the main risk for the patient is a false diagnosis of mycosis, followed by an unnecessary and inefficient treatment. As a reminder, an anti-fungal treatment, especially oral, must not be initiated if the presence of a fungus has not been detected.

Dermatology practical sheets

214.08.2010 © Club Dermaweb ı http://www.clubdermaweb.com

What needs to be said!

This will heal on its own, no treatment is necessary. Indeed, there is no efficient treatment. In the case of pruritus or if the patient finds the presence of the lesions difficult to cope with, low dose local corticosteroid therapy (level II or III) can reduce the symptoms.

D.Wallach, MD - Club dermaweb

Second eruption, florid.

D.Wallach, MD - Club dermaweb