Tinea versicolor, also known as pityriasis versicolor, is a common fungal infection affecting the top layer of the skin. It causes small, discolored patches that stand out from the surrounding skin tone. The name “versicolor” means “of various colors,” which aptly describes the condition, as the patches can be hypopigmented (lighter than the skin), hyperpigmented (darker than the skin, often pinkish or tan-brown), or reddish.

The condition is caused by an overgrowth of a type of yeast (a single-celled fungus) from the genus Malassezia. It is crucial to understand that Malassezia is a normal part of the skin’s microbiome, meaning it is a microorganism that lives harmlessly on the skin of most adults without causing any problems.

To understand why it sometimes causes a rash, it is helpful to use an analogy. Think of your skin’s surface as a diverse garden with many different types of microscopic “plants” (yeasts and bacteria) all living in a natural balance. The Malassezia yeast is like a normal, well-behaved succulent in this garden. In most conditions, it’s a quiet resident. In tinea versicolor, certain environmental factors, primarily heat, humidity, and oily skin act like a potent, specialized fertilizer for this particular succulent. It begins to overgrow and change its form, spreading out of control and disrupting the appearance of the ‘lawn’ (your skin’s pigment), creating the characteristic discolored patches.

In my clinic, I often see patients worry they have vitiligo or eczema when it’s actually tinea versicolor. The key clue is that the patches are usually faintly scaly and show up more in hot, humid months.

Tinea versicolor is caused by the proliferation and transformation of the Malassezia yeast on the skin’s surface. This overgrowth disrupts the function of the melanocytes, the cells in our epidermis that are responsible for producing melanin, the pigment that gives our skin its color.

The color change mechanism is fascinating. The overgrown Malassezia yeast produces a substance called azelaic acid. This chemical has a bleaching effect; it interferes with the normal production of melanin by the melanocytes.

• In individuals with tanned or naturally dark skin, this blockage of melanin production results in patches that are lighter than the surrounding skin (hypopigmentation). This is why the condition often becomes much more noticeable in the summer months after sun exposure, the surrounding skin tans, while the affected patches do not, making them stand out.
• In individuals with pale skin, the inflammation caused by the yeast overgrowth can sometimes lead to patches that are pinkish or tan-brown (hyperpigmentation).

This dual ability to either lighten or darken the skin is what gives tinea versicolor its name.

I often tell patients that tinea versicolor is like a garden weed, it’s always there in small amounts but can flourish when conditions are just right, like during summer or after intense workouts.

You don’t catch tinea versicolor from someone else, it’s an endogenous condition, meaning it originates from within your own skin flora. The Malassezia yeast that causes the condition is already present on nearly all human skin.

A person develops the visible rash of tinea versicolor not from acquiring the fungus, but when the conditions on their own skin change in a way that encourages the normally harmless yeast to overgrow and flourish. The factors causing this overgrowth are very common.

The primary risk factors and triggers include:

• A Hot, Humid Climate: This is the biggest factor. The yeast thrives in warm, moist environments.
• Excessive Sweating (Hyperhidrosis): People who sweat heavily, whether from physical activity or their natural disposition, are more prone to the condition.
• Oily Skin: Malassezia feeds on the lipids (oils) in human sebum, so oily skin provides an ideal nutrient source for its overgrowth.
• Hormonal Changes: The condition often first appears during adolescence, when hormonal changes can increase oil production in the skin.
• A Weakened Immune System: Individuals with a compromised immune system, either from a medical condition like diabetes or from taking immunosuppressant medications like corticosteroids, may be more susceptible.

Many patients are surprised to hear this is a yeast we all have. I explain that it’s not about catching something, it’s about your skin reacting to changes like sweat, oil, and heat.

The primary and often only symptom of tinea versicolor is the appearance of the characteristic skin patches.

The key features of the rash include:

• Appearance: The condition presents as multiple small, oval, well-demarcated macules (flat spots) or patches.
• Color: As the name “versicolor” implies, the color is variable. The patches can be white, pink, tan, or reddish-brown.
• Location: The rash is most commonly found on the oily areas of the body, particularly the upper trunk (chest and back), upper arms, and neck. It can occasionally affect the face, especially in children.
• Scaling: The patches often have a very fine, dust-like scale. This scaling may not be immediately obvious but can often be seen by gently scratching the surface of a patch (a finding known as the “scrape sign”).
• Merging: The small individual spots often merge together to form larger, more noticeable patches.

Typically, the rash of tinea versicolor is asymptomatic or causes only mild itching. The main concern for most people is the cosmetic appearance of the discolored skin. A key feature is that the affected patches do not tan. This means that after sun exposure, the patches often appear much lighter than the surrounding tanned skin, which is when many people first seek medical attention.

What I’ve often seen is that patients don’t notice the patches until the tanning season. The contrast between affected and normal skin becomes especially apparent after sun exposure.

Most cases are clinically diagnosed by skin appearance. Additional tests may be done to confirm the diagnosis if the presentation is unclear.

• Clinical Examination: The characteristic pattern of small, discolored, slightly scaly patches in the typical locations (chest, back, and upper arms) is often enough for a confident clinical diagnosis.
• Wood’s Lamp Examination: In some cases, a doctor may use a Wood’s lamp to help confirm the diagnosis. This is a special handheld device that emits ultraviolet (UVA) light. When shone on the affected skin in a dark room, the Malassezia yeast often gives off a distinctive yellowish-green fluorescence.
• KOH Preparation: The definitive diagnosis can be made with a simple, painless, in-office test called a KOH preparation. A doctor will use a scalpel blade or a glass slide to gently scrape a small sample of the fine scale from an affected patch. This sample is placed on a microscope slide, and a drop of potassium hydroxide (KOH) solution is added to dissolve the skin cells. When the sample is viewed under the microscope, the Malassezia fungus reveals a classic and unmistakable pattern described as “spaghetti and meatballs,” which represents the combination of the long, filamentous hyphae (the “spaghetti”) and the round yeast forms (the “meatballs”). This finding confirms the diagnosis of tinea versicolor.

A Wood’s lamp can be a game-changer, it highlights affected areas in seconds. I often use it when the discoloration is subtle or when patients worry it’s something more serious.

Treatment focuses on reducing the yeast overgrowth and preventing recurrence.

A crucial point for patients to understand: Even after the fungus has been successfully killed, the discolored patches will remain. It can take several weeks to months for the skin’s melanocytes to recover and for the skin tone to return to normal.

1. Topical Treatments (First-Line Therapy)

For most tinea versicolor cases, treatment consists of topical antifungal medications that are applied directly to the skin.

• Medicated Shampoos: This is the most common and effective treatment. Over-the-counter or prescription shampoos containing selenium sulfide or ketoconazole are the mainstay of therapy. The typical method is to apply the shampoo to all affected areas of the body, let it sit on the skin for 5 to 10 minutes, and then rinse it off thoroughly. This is usually repeated daily for 1 to 2 weeks.
• Antifungal Creams and Lotions: Other topical antifungal creams, such as those containing clotrimazole or miconazole, can also be used, but they can be more difficult to apply to large areas of the back and chest.

2. Oral Medications

For cases that are very widespread, severe, or that frequently recur despite proper topical therapy, a doctor may prescribe a short course of oral antifungal pills.

• Fluconazole or itraconazole are the most commonly used oral medications. They are highly effective but carry a greater risk of side effects than topical treatments and require a prescription and monitoring by a doctor.

3. Preventing Recurrence (Maintenance Therapy)

Tinea versicolor has a very high rate of recurrence, especially for individuals who live in hot, humid climates. Once the initial infection has been cleared, a maintenance plan is often required to prevent the yeast from overgrowing again.

• The most common maintenance strategy is to use the medicated antifungal shampoo (selenium sulfide or ketoconazole) once or twice a month, particularly during the warmer, more humid seasons. This helps keep the yeast population on the skin in check.
• Other preventative measures include wearing loose, breathable clothing and showering promptly after sweating or exercising.

Patients often worry the treatment isn’t working because the color takes time to return. I reassure them that once the yeast is gone, the pigment will slowly recover, it’s just a waiting game.

Tinea versicolor is a very common, harmless, and non-contagious skin condition caused by an overgrowth of the normal skin yeast Malassezia. Triggered by heat, humidity, and oily skin, it results in discolored patches on the trunk and upper arms that are primarily a cosmetic concern. While the appearance of the patches can be a source of anxiety, it is important to remember that the condition is easily diagnosed by a doctor and responds very well to simple and effective treatments, most commonly over-the-counter or prescription antifungal shampoos. Recurrences are common, but they can be managed with a simple, periodic maintenance routine.

American Academy of Dermatology (AAD). (n.d.). Tinea versicolor: Overview. Retrieved from https://www.aad.org/public/diseases/a-z/tinea-versicolor-overview

Mayo Clinic. (2022). Tinea versicolor. Retrieved from https://www.mayoclinic.org/diseases-conditions/tinea-versicolor/symptoms-causes/syc-20378385

DermNet NZ. (n.d.). Pityriasis versicolor. Retrieved from https://dermnetnz.org/topics/pityriasis-versicolor