White patches on the skin are a sign of the condition known by dermatologists as pityriasis. Specifically, pityriasis versicolor appears more when one is suntanned. However, it is not produced by the sun, but rather by a fungus that lives on healthy skin.
Why do white spots appear on the skin?
Pityriasis versicolor is a superficial skin condition caused by the high presence of a fungus, but it is not considered an infectious illness. The cause of the condition is a gene of fungus, called Malassezia, which is normally present in human skin. It is naturally found on the skin of both humans and animals. When significant pityriasis occurs, it means that too much of this fungus is being produced.
What does pityriasis look like?
Pityriasis is characterised by the appearance of white marks on the skin, appearing on the upper part of the torso, neck and tops of the arms. They are irregular, and can initially appear slightly brown in colour with light peeling on the surface.
Pityriasis is not produced by the sun, although this is often a cause of confusion because patients see it more in summer. This is simply because when the patient is tanned it is more visible. Furthermore, this fungus particularly likes warm, humid environments, so it is more commonly seen in the summertime.
How is pityriasis diagnosed?
Diagnosis is clinical and can be carried out by an experienced dermatologist. A skin scraping under a microscope can show flakes, or it may be possible to verify using lab cultures.
What is the treatment for skin fungus?
Treatment involves applying a topical anti-fungal substance for a period of 2 to 4 weeks. In patients with frequent outbreaks, or where the topical treatment is not working, oral treatment may be prescribed. However, the treatment does not make the marks disappear immediately. The marks on the skin will improve over a period of months once the level of the fungus has been reduced.
Pityriasis alba, another type of mark on the skin
What is pityriasis alba?
This condition appears as white marks on the skin with no clearly defined borders and in various sizes, usually located on the arms, legs and face. Its cause is not known and it is usually more visible when the patient initially becomes tanned. It is normally associated more with patients who have atopic dermatitis, and young patients. It is connected to skin dryness and irritation, and a lack of even pigmentation as a result of sun exposure.
When treating pityriasis alba it is vital to keep the skin hydrated and protect it from the sun. It is also advisable to use detergent-free soaps.