There pityriasis rosea, first described in 1860 by dermatologist Camille-Melchior Gibert and initially called roseola anulata, is a benign skin disease that occurs suddenly and is characterized by the appearance of a reddish and scaly patch, oval in shape and 1 to 3 cm in diameter, called mother spot or Gibert medallion. After a few days, the mother spot it is followed by the appearance on the trunk of other similar but smaller spots, which take on a characteristic "Christmas tree" arrangement.
Pityriasis rosea it is a disease that usually does not cause disturbances (symptoms) and only in rare cases can it itch. Unlike other exanthematous diseases, it is not contagious. It most commonly affects children and young adults between the ages of 10 and 35 and occurs mainly in spring and autumn. There pityriasis rosea spontaneously heals within 40-60 days of onset without any treatment. It cannot be prevented and at times it can recur (relapse) even after many years but in a very mild form.
There pityriasis rosea it mainly affects children and young adults between 10 and 35 years of age, without distinction of sex, but it can also be found in older age. It manifests itself with the appearance, on the back, chest or abdomen, of a characteristic reddish, scaly and slightly raised spot, called mother spot, which can reach up to 10 cm in diameter. Before this happens, some people may experience general ailments such as headaches, fatigue, fever and joint pain.
A few days or weeks after the appearance of the mother spot, a more widespread "rash (rash)" (secondary rash) develops, which may continue to spread over the next 2-6 weeks. This type of rash is characterized by smaller scaly patches (0.5-1.5 cm in diameter) called daughter spots. They are arranged in a radial pattern in a symmetrical way, like the branches of a fir tree, and can appear on the chest, back, belly, neck, scalp and upper part of the limbs. The face is usually not affected. In dark-skinned people, the spots can also be gray, dark brown, or black.
Except in some cases where it can be itchy (especially in children suffering from atopic dermatitis), the disease generally does not cause appreciable disturbances and heals spontaneously within 2-12 weeks. It is advisable to consult your doctor to rule out other diseases with symptoms similar and when the rash is persistent.
The causes of the pityriasis rosea but recent studies suggest that reactivation of some herpes virus strains in particular herpes 6 which causes the sixth disease in infancy, may contribute to its development. The disease, however, is not considered contagious and only very few cases of spread within the family nucleus have been described. It is therefore possible to lead a normal life and not isolate yourself.
The diagnosis of pityriasis rosea is carried out by the doctor by observing the spots. However, the mother spot may look similar to that seen in some fungal skin infections such as tinea corporis (commonly called "ringworm"), or in "nummular eczema (a form of dermatitis) or in diseases such as psoriasis or lichen, which are characterized by long-lasting (chronic) inflammation of the skin.
In 20% of cases, atypical forms of pityriasis rosea which can make it less easy to identify. For example:
- mother patch absent or undetectable
- localized patches in the creases of the elbows and knees (reverse form)
- large patches on the scalp, genitals, oral mucosa and nails (giant form)
- patches similar to hives or with blisters and scabs
- intense itching or persistent rash for many months
In doubtful cases, the doctor can help the doctor tell the personal and family history of the sick person (anamnesis), the careful observation of the spots and the microscopic examination of the material obtained by scraping the skin (especially to exclude tinea corporis). Skin biopsy is generally not necessary.
There pityriasis rosea normally it does not require any pharmacological treatment as it is a disease that does not cause major disturbances, heals spontaneously within a maximum of 12 weeks, does not leave scars and can only rarely recur (relapse), in a mild form, after years.
Instead, it is necessary to treat itching in itchy forms, especially in children, with menthol talc and soaps / emollient creams or antihistamines, and not scratch the skin to avoid infections.
There pityriasis rosea it is a so-called disease self-limiting, that is to say that it heals on its own without leaving any traces. However, in some conditions, for example in pregnancy, it could lead to complications. The disease, in fact, is more frequent in pregnant women, probably due to alterations in the immune response, and if it appears in the first 15 weeks of gestation it can increase the risk of spontaneous abortion.
Drago F, Ciccarese G, Rebora A, Broccolo F, Parodi A. Pityriasis Rosea: A Comprehensive Classification. Dermatology. 2016; 232: 431-437
Bambino Gesù Children's Hospital. Gibert's Pityriasis rosea
Mayo Clinic. Pityriasis rosea (English)
NHS. Pityriasis rosea (English)