When the skin becomes lighter despite tanning

What is pityriasis versicolor?

Pityriasis versicolor (Pityriasis versicolor) is a harmless skin condition caused by an excessive growth of yeasts of the genus Malassezia. These yeasts normally inhabit the skin, especially the hair follicles and adjacent areas, particularly on the scalp, and are usually harmless. However, when they multiply extensively, skin changes occur that appear as patches with varying pigmentation.

Characteristic for the condition are flaky shedding of the outermost skin layers, resembling bran. This appearance is the reason for the common name. The fungal infection mainly affects the chest and back, but it is not contagious. Although the skin changes respond well to treatment, they can recur over time.

How does pityriasis versicolor present?

Pityriasis versicolor usually begins with small, round or oval skin spots. Over time these can merge to form larger, irregularly shaped patches. The changes preferentially occur on the back, chest, neck and arms. In children the face can also be affected. 

The patches vary in colour and, depending on skin type, appear yellowish, brownish, reddish or pink. On darker or tanned skin they usually stand out as lighter spots, while on very fair skin they often appear darker.

The affected areas are marked by slight scaling. Itching is uncommon and, if present, is usually mild. Unlike healthy skin, the affected areas react little to sunlight because the yeasts inhibit melanin production. As a result these skin areas do not darken or lighten with tanning in the same way as surrounding skin, making the difference clearly visible.

What causes pityriasis versicolor?

The development of pityriasis versicolor is closely linked to the yeast Malasseziafurfur, which naturally occurs on the skin. It is part of the normal skin flora in most adults. Normally this yeast does not cause health problems, but under certain conditions it can overgrow and cause the characteristic skin changes. Areas of skin with increased sebum production, such as the face, scalp or torso, provide ideal conditions for the yeast because it relies on skin fatty acids.

Various factors promote yeast growth and thereby the development of the condition. An important role is played by a warm and humid climate, which is why pityriasis versicolor is more common in tropical and subtropical regions. Increased sweating also keeps the skin moist and supports yeast proliferation – hence the pathogen is sometimes referred to as a "sweat fungus".

People with oily skin also have a higher risk, as the larger amount of sebum provides the yeast with an additional source of nutrients. A weakened immune system – for example due to illness, stress or certain medications – reduces the body's defence against fungal growth, making infection more likely.

Changes in hormonal balance, such as those occurring during puberty, pregnancy or with the use of hormonal contraceptives, can also affect skin condition and favour the development of pityriasis versicolor. It is important to know that poor hygiene does not influence the occurrence of the condition.

Is pityriasis versicolor dangerous?

Pityriasis versicolor is essentially a harmless skin condition that does not cause health complications. For healthy individuals it represents primarily a cosmetic problem because it alters the appearance of the skin but causes no significant physical symptoms. Nevertheless, the condition can be psychologically distressing because it often persists and the visible skin changes may affect self-esteem.

In people with weakened immune systems, pityriasis versicolor can sometimes lead to secondary inflammation. In such cases hair follicles may become inflamed and small, pus-filled nodules that can be painful may form.

How is it treated?

Treatment of pityriasis versicolor depends primarily on the extent of the condition and the individual's predisposition. In most cases topical antifungal agents are used first to inhibit the yeast's growth or kill the organisms. 

Creams, lotions or shampoos containing active ingredients such as clotrimazole, bifonazole or ketoconazole are commonly used. These products are applied to the affected skin areas as well as the scalp, since the yeast often persists there as a reservoir and can promote reinfection. The contact time for the medications varies depending on the product and recommendation.

If topical treatment is insufficient, for example with extensive involvement, recurrent infections or inadequate therapeutic response, systemic therapy may be necessary. In that case antifungal tablets such as itraconazole or fluconazole are taken for several days. 

Although medications treat the infection, the skin often needs more time for the discolourations to disappear completely and for pigmentation to normalise. In some cases it is advisable to continue using antifungal agents for several weeks after symptoms subside to prevent relapses. 

How to prevent pityriasis versicolor: useful tips

• Avoid body-care products that heavily grease the skin. Especially in warmer months, oil-rich creams or certain sunscreens can increase sebum production, which in turn favours yeast growth.
• Use mild soaps or shower gels for daily cleansing that respect your skin's natural pH of around 5.5. This supports the skin's acid mantle, which provides a natural defence against fungal infections.
• Maintain balanced skin hydration: skin that is too dry is not ideal, but excessive moisture from sweating or heavy moisturisers can promote yeast growth.
• If you already suffer from pityriasis versicolor or are prone to relapses, discuss with your doctor the long-term preventive use of antifungal shampoos.
• Shower promptly after physical exertion or on hot days to thoroughly remove sweat. Since the yeast prefers a warm, moist environment, quick removal of sweat helps limit its multiplication.
• Clothing matters: favour loose, breathable cotton fabrics. Tight clothing made from synthetic materials promotes excessive sweating and creates a humid environment in which the yeast can thrive. Cotton absorbs sweat well and promotes air circulation on the skin.
• Also change tight clothing and towels daily to prevent recolonisation of the skin by yeasts. Wash these preferably at 90 °C.
• Pay attention to a comfortable indoor temperature and adequate ventilation to avoid heat build-up and excessive sweating. A cooler, drier indoor climate can reduce yeast growth on the skin.

With the right knowledge and appropriate care, pityriasis versicolor need not hold you back. Preventive measures help keep the skin protected and in balance.