Gibert’s pityriasis rosea:

a strange but very common exanthematous disease
What is it? It is one of the most common forms of dermatitis – a very particular exanthema that affects the majority of the population, usually between the ages of 10 and 35 years. 
What does it look like? It appears as a roundish or oval-shaped rash characterised by a slightly flaky border and a slightly reddened centre. This primary “herald” patch is followed by other similar but smaller patches after a few days.   Where does it appear? Particularly on the trunk, but sometimes also on the limbs; it is rarely seen on the face, hands or feet.   What does it feel like? It is not usually very bothersome; at most, there may be mild itching in the affected area.   What causes it? It has only recently been discovered that it is caused by a member of Herpes family of viruses, in particular Herpes virus VI/VII   Is it contagious? Strangely enough, this form of exanthema is not contagious. Are any precautions necessary? People affected by Gibert’s pityriasis rosea can lead a perfectly normal life, eat as usual, go to work, go out with friends, and so on. How long does it last? This is also strange: it may take one or more months (sometimes up to six) from the appearance of the first patch to the disappearance of them all. Does it leave any signs? After the disappearance of the patches, the skin returns to being perfectly normal. Can it recur? It usually only appears once, but it may recur a number of times in some people, even after a periods of years. Is it necessary to have a blood test? No changes in blood parameters occur during the disease, and so no tests are necessary. Is there any treatment? No. The dermatitis spontaneously disappears and there is no need to take any drugs. What can be done? During the period of the exanthema, the skin becomes very sensitive and so it is advisable to use a washing cream (Cleansing Cream); avoid direct sunlight or exposure to UV, and avoid wearing clothes made of wool or synthetic materials next to the skin. In the case of itching, use a Lenitive cream.