Malassezia Infection - Specialists and Information

Malassezia yeasts are found in the skin flora of humans and some warm-blooded animals. They feed primarily on long-chain fatty acids. The only exception here is the species M. pachydermatis.

Because they require a supply of long-chain fatty acids, Malassezia yeasts are very commonly found in sebum-rich areas of the skin.

Examples include:

• Scalp
• Face
• Front and back sweat grooves

According to current research, Malassezia yeasts are classified into twelve species.

The prevalence of these yeasts on the skin of a healthy person is primarily related to the person’s age. This is because sebaceous gland activity does not increase until puberty. From this point on, the skin becomes a favorable environment for colonization by Malassezia yeasts. It is only with age and the associated decrease in sebum production that the colonization density declines again.

Pityriasis versicolor (tinea versicolor) is the most common disease caused by a fungal pathogen of the genus Malassezia. The yeast responsible is Malassezia furfur.

In tropical regions, it is estimated that one in two people is affected. In temperate regions such as Germany, Austria, and Switzerland, however, only 1 percent of the population is affected.

Malassezia infection with pityriasis versicolor occurs in two different forms. Experts distinguish between:

• Pityriasis versicolor chromians and
• Pityriasis versicolor alba

Symptoms and Appearance of Pityriasis versicolor

Pityriasis versicolor chromians presents as a hyperpigmented form. The hyperpigmentation usually appears in a rounded shape. The patches occur particularly in sebaceous areas of the skin. However, the condition can also affect other parts of the body, such as the abdomen and arms.

A distinctive feature is the variety of colors in the patches or areas of hyperpigmentation. They are usually covered by scaling. However, under long-wave UV light, they exhibit a yellow-green fluorescence.

Pityriasis versicolor is a skin condition in which a harmless skin fungus suddenly multiplies rapidly @ buraratn_100 /AdobeStock

If long-lasting depigmentation remains after the hyperpigmented patches have healed, experts refer to this as pityriasis versicolor alba.

This form of Malassezia infection primarily affects adults. It is difficult to treat. Improvement in the infection occurs only slowly. In any case, professional help is needed.

It is not entirely clear how such an infection occurs.

Medical professionals often believe it is an allergic reaction caused by an increased concentration of Malassezia yeasts.

Other medical professionals, however, believe that these yeasts usually have a pathological effect only on certain at-risk groups. At-risk groups include pregnant women and immunocompromised individuals.

Still other medical professionals suspect a link between these risk groups and an allergic reaction.

Therefore, it can be said that virtually no one is safe from a Malassezia infection. However, if you belong to one of the risk groups, you are more likely to develop the condition.

Pityriasis versicolor is generally only a cosmetic problem. The hyperpigmented patches are long-lasting and spread over large areas of the skin.

A superficial fungal infection is not dangerous and is not life-threatening. However, you should not take the condition lightly and should have it examined by a specialist.

In some cases, a superficial fungal infection can progress to a systemic fungal infection. This occurs when the skin is severely compromised and pathogens enter the body. A systemic fungal infection affects the body’s internal organs, which can lead to death.

The diagnosis is initially made through a physical examination. During this examination, the doctor closely examines the affected area and then takes a sample.

They usually scrape off a few skin flakes, which they then examine under a microscope. Using a so-called KOH preparation, the doctor can determine with certainty whether a Malassezia infection is present.

If the doctor finds “spaghetti and meatballs”-like clusters of round budding cells and hyphae, a definitive diagnosis is confirmed.

Treatment usually involves topical therapy. Doctors use external applications to contain and destroy the pathogen. 

This usually involves ointments, gels, special shampoos, or creams. Patients apply these substances to the affected skin at regular intervals.

It is recommended to apply the ointments before bedtime to allow for a longer exposure time @ Olga Ternavskaya /AdobeStock

This is important because pathogens may also be present around the site of infection. You should make sure to thoroughly disinfect any clothing that has come into contact with the fungal infection. This is the only way to ensure that topical therapy is successful.

To ensure that topical therapy is effective, doctors also use solutions that patients apply to their entire body.

This is primarily used when the lesions cover a large area.

Topical therapy involves the use of so-called antifungal agents. Antifungals from the azole group, ciclopirox olamine, and terbinafine are used. These have been proven effective in studies.

• Malassezia folliculitis

This condition is also caused by Malassezia yeasts. However, it is not very common. Those affected find it particularly bothersome that the patches itch and pustules form. 

Doctors also treat Malassezia infections with antifungal medications, which usually provide rapid relief from symptoms.

• Malassezia dermatitis in animals

This condition can occur not only in humans but also in animals. It is particularly common in dogs. 

In animals, this condition is called Malassezia dermatitis. In dogs, it is often diagnosed late because most owners do not notice the symptoms. They assume it is fleas. The thick coat also makes it harder for owners to visually detect the condition.

Animals also experience hyperpigmentation, which usually affects a large area. Thickening of the skin is also not uncommon. Dogs particularly often struggle with infections affecting their paws and claws. 

Frequent licking of the paws is a typical warning sign. Inflammation of the nail beds or discoloration of the nails can also be signs of a fungal infection. 

If your dog experiences severe itching and redness, you should see a veterinarian immediately, as dogs often scratch themselves until they bleed. Scratching can allow pathogens to enter the body and lead to more serious complications. It also prolongs the healing process and increases the animal’s pain.

The ears, underside of the neck, paws, and armpits are particularly commonly affected @ weerachaiphoto /AdobeStock

Both humans and animals should see a healthcare professional if they experience flaking or redness and have it treated. Treatment is especially important if the affected areas are extensive. Even though Malassezia fungi are generally harmless, they can lead to serious consequences in some rare cases.