eMedicine Specialties > Dermatology > Bacterial Infections

Trichomycosis Axillaris

Author: Zeina Nehme Ghorayeb, MD, Lecturer, University of Balamand School of Medicine
Coauthor(s): Mona Matta-Muallem, MD, Associate Professor, Department of Dermatology, American University of Beirut, Lebanon
Contributor Information and Disclosures

Updated: Nov 13, 2009

Introduction

Background

Trichomycosis axillaris is a relatively common superficial bacterial colonization of the axillary hair shafts. Granular concretions, which are yellow, black, or red, adhere to the hair shaft and clinically characterize trichomycosis axillaris.

Pathophysiology

Trichomycosis axillaris results from corynebacterial overgrowth on hair shafts in moist regions of the body and predominantly affects axillary hair, and to a lesser extent, pubic hair (trichomycosis pubis).1 Shelley and Shelley noted the coexistence of erythrasma, trichomycosis axillaris, and pitted keratolysis and termed it the corynebacterial triad.2 Rho and Kim reported the corynebacterial triad in 13% of 842 Korean soldiers.3

Frequency

United States

No studies have assessed the frequency of trichomycosis axillaris in the United States.

International

In one study from the United Kingdom, trichomycosis axillaris was present in 27% of adult male students, and in the general population, 42% of male patients and 7% of female patients.

Mortality/Morbidity

Trichomycosis axillaris is a benign disease with no associated mortality or complications.

Race

No racial predilection is reported for trichomycosis axillaris.

Sex

Both sexes may be affected; however, trichomycosis axillaris appears to affect males more commonly, since most women shave their axillary hair.

Age

Trichomycosis axillaris can affect any age group from puberty through adulthood.

Clinical

History

  • Trichomycosis axillaris typically is asymptomatic; however, patients may report malodorous sweat.
  • Trichomycosis axillaris may be associated with similar findings of hair concretions in the pubic area (trichomycosis pubis).

Physical

  • Concretions encircle the hair shaft, making it appear beaded or thicker. Concretions are most common on the central portion of axillary hair.
  • Concretions consist of 1- to 2-mm red, black, or yellow nodules that adhere firmly to the hair shaft. The insoluble cement substance elaborated by the bacteria adheres to the hair shaft and, occasionally, invades and destroys cuticular and cortical keratin. The yellow color is observed most commonly (see Media File 1) and may stain clothes yellow. Black and red are seen most commonly in tropical climates.
  • The hair shaft may become brittle and thus, more easily broken, but this is rare. Typically, since the hair shaft is not weakened, alopecia is not seen.
  • The underlying skin usually is normal, although hyperhidrosis of the affected regions is common.
Yellow concretions are seen over axillary hairs.

Yellow concretions are seen over axillary hairs.

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Yellow concretions are seen over axillary hairs.

Yellow concretions are seen over axillary hairs.


Close-up view of axillary hairs.

Close-up view of axillary hairs.

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Close-up view of axillary hairs.

Close-up view of axillary hairs.


Causes

Trichomycosis axillaris is caused by several species of the gram-positive diphtheroid Corynebacterium,4 not by a fungus as the name may imply.

More on Trichomycosis Axillaris

Overview: Trichomycosis Axillaris
Differential Diagnoses & Workup: Trichomycosis Axillaris
Treatment & Medication: Trichomycosis Axillaris
Follow-up: Trichomycosis Axillaris
Multimedia: Trichomycosis Axillaris
References
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References

  1. Freeman RG, McBride ME, Knox JM. Pathogenesis of trichomycosis axillaris. Arch Dermatol. Jul 1969;100(1):90-5. [Medline].

  2. Shelley WB, Shelley ED. Coexistent erythrasma, trichomycosis axillaris, and pitted keratolysis: an overlooked corynebacterial triad?. J Am Acad Dermatol. Dec 1982;7(6):752-7. [Medline].

  3. Rho NK, Kim BJ. A corynebacterial triad: Prevalence of erythrasma and trichomycosis axillaris in soldiers with pitted keratolysis. J Am Acad Dermatol. Feb 2008;58(2 Suppl):S57-8. [Medline].

  4. Savin JA, Somerville A, Noble WC. The bacterial flora of trichomycosis axillaris. J Med Microbiol. May 1970;3(2):352-6. [Medline].

  5. Shelley WB, Miller MA. Electron microscopy, histochemistry, and microbiology of bacterial adhesion in trichomycosis axillaris. J Am Acad Dermatol. Jun 1984;10(6):1005-14. [Medline].

  6. Korting GW. Practical Dermatology of the Genital Region. Philadelphia, Pa: WB Saunders; 1980:59.

  7. Levit F. Trichomycosis axillaris. J Am Acad Dermatol. May 1990;22(5 Pt 1):858-9. [Medline].

  8. Levit F. Trichomycosis axillaris: a different view. J Am Acad Dermatol. Apr 1988;18(4 Pt 1):778-9. [Medline].

  9. McBride ME, Duncan WC. Trichomycosis axillaris. Arch Dermatol. Mar 1972;105(3):459. [Medline].

  10. Wilson C, Dawber R. Trichomycosis axillaris: a different view. J Am Acad Dermatol. Aug 1989;21(2 Pt 1):325-6. [Medline].

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Further Reading

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Keywords

trichomycosis axillaris, trichomycosis nodosa, lepothrix

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Contributor Information and Disclosures

Author

Zeina Nehme Ghorayeb, MD, Lecturer, University of Balamand School of Medicine
Zeina Nehme Ghorayeb, MD is a member of the following medical societies: Alpha Omega Alpha
Disclosure: Nothing to disclose.

Coauthor(s)

Mona Matta-Muallem, MD, Associate Professor, Department of Dermatology, American University of Beirut, Lebanon
Mona Matta-Muallem, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

Medical Editor

Susan M Swetter, MD, Director, Pigmented Lesion and Cutaneous Melanoma Clinic, Associate Professor, Department of Dermatology, Stanford University Medical Center, Veterans Affairs Palo Alto Health Care System
Susan M Swetter, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Association, American Society of Clinical Oncology, Eastern Cooperative Oncology Group, Pacific Dermatologic Association, Society for Investigative Dermatology, Society for Melanoma Research, and Women's Dermatologic Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University School of Medicine; Consulting Staff, Mountain View Dermatology, PA
Richard P Vinson, MD is a member of the following medical societies: American Academy of Dermatology, Association of Military Dermatologists, Texas Dermatological Society, and Texas Medical Association
Disclosure: Nothing to disclose.

Managing Editor

Jeffrey J Miller, MD, Associate Professor of Dermatology, Penn State University College of Medicine; Staff Dermatologist, Penn State Milton S Hershey Medical Center
Jeffrey J Miller, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Association of Professors of Dermatology, North American Hair Research Society, and Society for Investigative Dermatology
Disclosure: Nothing to disclose.

CME Editor

Joel M Gelfand, MD, MSCE, Medical Director, Clinical Studies Unit, Assistant Professor, Department of Dermatology, Associate Scholar, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania
Joel M Gelfand, MD, MSCE is a member of the following medical societies: Society for Investigative Dermatology
Disclosure: AMGEN Consulting fee Consulting; AMGEN Grant/research funds None; Genentech Consulting fee Consulting; Centocor Consulting fee Consulting; Centocor Grant/research funds None; Covance Consulting fee Consulting; Shire  Consulting

Chief Editor

Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

 
 
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