eMedicine Specialties > Dermatology > Bacterial Infections

Trichomycosis Pubis

Author: Vladimir O Osipov, MD, Assistant Professor, Department of Pathology, Section of Bone and Soft Tissue Pathology, Section of Gastrointestinal Pathology, Medical College of Wisconsin
Coauthor(s): Scott M Acker, MD, Associate Professor, Director of Dermatopathology, Departments of Dermatology and Pathology, University of Alabama at Birmingham; Peter Langenstroer, MD, Associate Professor, Department of Urology, Medical College of Wisconsin; Milton W Datta, MD, Assistant Professor, Departments of Pathology, Urology, and Hematology-Oncology, Emory University School of Medicine
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Updated: Mar 26, 2009

Introduction

Background

Trichomycosis is a bacterial infection of the hair shaft found in sweat gland–bearing areas; it has been described most commonly in the axillary region. While initially believed to be uncommon in the inguinal region, a series of papers have described trichomycosis particular to the inguinal area and have suggested that this disease is underestimated in the general population.

Pathophysiology

This discussion of trichomycosis, a disease specific to the hair and sweat gland–bearing regions of the body, concentrates on the involvement of the pubic region in men (trichomycosis pubis). First described in the axillary region by Paxton in 1869, the causative role of multiple bacterial Corynebacterium species was established by Freeman et al in 1969.^1,2,3,4,5 Use of the term trichomycosis, and the implied causative role of fungi, has been maintained. The color differences noted at presentation of the condition, their association with particular corynebacteria, or the possible role of associated cocci have not been clarified.

The causative organism associated with most cases is Corynebacterium tenuis, which prefers the moist microenvironment of the inguinal regions. While as many as 33% of adults have colonization by bacteria in the inguinal or axillary regions, factors such as hyperhidrosis initiate more extensive growth and clinical manifestation. The exact origin of the cement substance that creates the grossly visible nodules is debated. Electron microscopy studies favor origin from the causative agents, while others have favored elaboration from apocrine sweat.^6,7 The actual nidus may be through the modification of apocrine sweat by elaborated cement substance to create the insoluble material that holds bacteria to the hair shaft.

Rho et al describe a so-called "corynebacterial triad" that includes erythrasma and trichomycosis axillaris in soldiers with pitted keratolysis.⁸

Frequency

United States

Detailed examination of racial, age, or geographic incidence has not been performed, and examinations in the United States are limited to case reports. A more detailed examination (but still limited) has been performed outside the United States.

International

Studies in Panama and the United Arab Emirates revealed rates as high as 39% in patients attending a dermatology clinic.^9,10 These results correlated with the notably higher incidence in areas of high humidity, warmth, and poor hygiene. The only other study to mention incidence noted the presence of trichomycosis pubis when examining institutionalized mentally retarded patients for trichomycosis axillaris in Edinburgh, Scotland, and noted that of 609 men examined, 16 (2.6%) had pubic disease, of which 3 of the cases (0.5%) were not associated with axillary involvement. Ages of the males affected were 18 and 21 (3 patients) and can be culled only from case reports.

Mortality/Morbidity

Morbidity is low, with most patients unaware of the colonization. When presenting, the most common complaint is a foul odor, and this may continue to cause problems, since trichomycosis often recurs.

Clinical

History

While many patients are asymptomatic, patients have presented because of pubic rash, foul odor, or growths on the pubic hair. Presenting complaints of colored sweat also have been recorded, resulting in a consideration of chromhidrosis.

Physical

Patients typically present with yellow or red nodules on the hair shafts; yellow is most common. Sweat in the region tends to be colored similarly. Lesions present in the inguinal region, often on the scrotum but occasionally on the base of the shaft of the penis. Lesions can be associated with erythema and itching, and superinfection with dermatophytes has been noted.

Causes

Risk factors appear to be geographic, with the highest incidence in tropic areas. In addition, poor hygiene often is present.

Other diagnostic considerations

Clinical separation from other organisms often is not performed, and treatment focuses on the empirical use of drying agents and topical antibiotics. Thus, the use of topical powders can be a confounding factor in diagnosis. True fungal infections (piedra) also may confound the diagnosis but may be present as superinfection. Piedra presents with nodularity of the hair shafts that is either tan to white (white piedra) or black (black piedra), as opposed to the yellow or red nodules of trichomycosis. White piedra may have a gelatinous appearance.

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