What are the risk factors for Malassezia (Pityrosporum) folliculitis?

Updated: Apr 03, 2020
  • Author: Sarah Sweeney Pinney, MD, FAAD; Chief Editor: William D James, MD  more...
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Systemic diseases and pharmacologic agents that encourage the growth of yeast, possibly because of alterations in immunity, include the following:

  • Diabetes mellitus

  • Cushing disease

  • Hodgkin disease [6]

  • Cancer treated with cetuximab (IMC-C225; marketed under the name Erbitux), a chimeric (mouse/human) monoclonal antibody epidermal growth factor receptor (EGFR) inhibitor for the treatment of metastatic colorectal cancer and head and neck cancer [7]

  • HIV infection

  • Corticosteroids and/or immunosuppressant therapy following organ transplantation [8, 9, 10]

  • Crohn disease treated with infliximab a monoclonal antibody against tumor necrosis factor alpha. [11]

An increase in sebum production, such as that in pregnancy, [12, 13] and high levels of androgens may potentiate the development of Pityrosporum folliculitis.

Antibiotics can alter normal skin flora, allowing the yeast to proliferate.

Pityrosporum folliculitis more frequently occurs in environments of high heat and humidity.

Occlusion of the skin and hair follicles with cosmetics, lotions, sunscreens, emollients, olive oil, or clothing creates favorable conditions for Pityrosporum folliculitis.

Anticonvulsant therapy and Down syndrome [14] are other conditions that are associated with Pityrosporum folliculitis.

Other related and coexisting conditions may include the following:

  • Seborrheic dermatitis

  • Confluent and reticulated papillomatosis

  • Systemic candidiasis [15]

Some individuals seem to have an innate propensity for Pityrosporum folliculitis. In one experiment, Malassezia yeasts were applied to occluded forearm skin in patients with Pityrosporum folliculitis. Flares of Pityrosporum folliculitis occurred at the application site. In the same experiment, Pityrosporum folliculitis did not develop in patients with no prior diagnosis of the condition.

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