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Microbiology · Yeasts and yeast-like fungi

Malassezia !

  • Fungus
  • For completeness

A yeast that normally lives on oily skin; with heat and sweat it overgrows and causes pale or dark patches with fine scale on the trunk and arms.

Updated 2026-11-01

Also called: Malassezia furfur, Malassezia globosa, pityriasis versicolor, tinea versicolor

At a glance

Shape
Clusters of round yeasts next to short filaments
Family
Malasseziaceae (Malasseziales, basidiomycete)
Type
Lipophilic skin yeast (in lesions: yeasts and short filaments)
Stain
KOH or tape strip with methylene blue; PAS on biopsy
Size
Yeasts of about 2–8 µm

Morphology

  • In scale: clusters of round yeasts mixed with short curved filaments
  • Needs lipids to grow: oil is added to culture media
  • Yellow-green fluorescence under Wood's lamp in some lesions

Transmission

  • Endogenous: part of normal skin flora
  • Not contagious
  • Heat, humidity, sweat and oily skin favour disease

Reservoir: Human skin with sebaceous glands

Isolation precautions

What the care team adds to standard precautions.

  • Standard

Virulence factors

  • Uses skin lipids as food
  • Azelaic acid and other products that disturb melanin production: pale patches
  • Switch from yeast to filament in the lesion

Diseases it causes

Clinical picture

  • Patches that do not tan and stand out after sun exposure
  • Fine scale that appears on scraping
  • Also linked to seborrheic dermatitis and folliculitis
  • Fungemia in newborns on lipid-rich parenteral nutrition (M. furfur)

Diagnosis

  • Clinical, supported by KOH or tape strip: round yeasts with short filaments
  • Wood's lamp
  • Biopsy with PAS if in doubt

Treatment

Topical antifungals (azoles such as ketoconazole shampoo or cream, selenium sulfide); oral azoles for extensive or recurrent disease. Relapses are common and the skin takes time to regain its colour.

Drug class only; doses and regimens are set by the clinician from the current guideline.

In Pharmacology:

Prevention

  • Topical maintenance in hot seasons for people who relapse
  • Reducing excess sweat and oils on the skin

Test yourself

Think of the answer, then tap the question to see it.

What does KOH show in a pityriasis versicolor lesion?

Clusters of round yeasts mixed with short filaments.

Why does Malassezia need oil in its culture medium?

It is lipophilic: it relies on outside lipids to grow, like those of oily skin.

Which serious infection can Malassezia furfur cause in newborns?

Fungemia linked to catheters delivering lipid-rich parenteral nutrition.

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← Back to the group: Yeasts and yeast-like fungi

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: Tinea versicolor: MedlinePlus Medical Encyclopedia (MedlinePlus (NLM), 2024); Tinea versicolor: Overview (American Academy of Dermatology, 2024).

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Representative model, for educational purposes only.