Trichobacteriosis Pubis Presenting as Genital Bromhidrosis

Dear Editor, Trichobacteriosis, previously known as trichomycosis, is a bacterial infection of the hair shaft caused by Coryneform Diphtheroids. It is cosmopolitan in distribution, but more common in the tropics. Depending on the location of affected hairs, it is further classified as trichomycosis axillaris, pubis, and capitis.[1] Trichobacteriosis pubis is a rare presentation and needs to be differentiated from white piedra, pediculosis pubis, hair casts, and trichorrhexis nodosa. They can be differentiated easily using bedside tests, such as trichoscopy, Wood's lamp examination, and microscopy. In trichobacteriosis pubis, the associated genital bromhidrosis impairs a patient's quality of life by interfering with one's sexual life. A 30-year-old married man presented with a complaint of malodour from the pubic region for 6 months, resulting in reluctance of the partner to engage in sexual activities. It was not associated with hyperhidrosis or itching. The patient was not on any medication and denied the use of any local application or consumption of garlic or onion in excess. Cutaneous examination showed firmly adherent, 2- to 10-mm-long yellowish concretions along multiple hair shafts in the pubic region, including the scrotum, associated with an offensive smell [Figure 1], which showed faint grey–white fluorescence under Wood's lamp [Figure 2]. Examination of the axilla and the gluteal region did not reveal any abnormalities. In vivo polarized trichoscopy showed pale-yellow cotton-like waxy structures forming sheaths, nodules, and concretions along the hair shafts in addition to the presence of both skewer and plume signs [Figure 3]. Ex vivo trichoscopy using polarized light showed yellowish waxy irregular casts adhering to the affected hair shafts [Figure 4]. Direct microscopy showed irregular concretions along the hair shafts [Figure 5]. Gram staining of the concretions revealed numerous gram-positive coccobacilli and amorphous material [Figure 6]. Potassium hydroxide (KOH) mount did not reveal any fungal elements. Based on history, clinical, Wood's lamp, trichoscopic, and microscopic examination, the patient was diagnosed as a case of bromhidrosis secondary to trichobacteriosis pubis and was advised to trim the pubic hairs and prescribed topical clindamycin 1% solution for local application two times per day. The patient noticed immediate improvement in malodour following trimming of hair, which completely resolved within a week leading to improvement in his sexual relationship with his partner.Figure 1: Firmly adherent, 2- to 10-mm-long concretions (green arrows) along multiple hair shafts over the scrotumFigure 2: Grey–white fluorescence (yellow arrows) along multiple hair shafts under Wood's lampFigure 3: In vivo polarized trichoscopy showing pale-yellow cotton-like structures forming concretions and nodules along the hair shafts with skewer sign (green arrow) and plume sign (red circle) (Dermlite 4, polarised, 10x)Figure 4: Ex vivo polarized trichoscopy showing yellowish waxy irregular casts adhering to the affected hair shafts (x210)Figure 5: Direct microscopy showing (a) irregular concretions along the hair shafts (x100); (b) yellow amorphous material encasing the hair (x400)Figure 6: Gram staining of the concretions showing numerous gram-positive coccobacilli and amorphous material (x400)Trichobacteriosis is a superficial bacterial infection of the hair shaft, especially of apocrine gland bearing sites, such as the axilla and the perineum. Rarely, scalp, eyebrows, and intergluteal sites can also get infected. The majority of the patients are male (94.6%) with a mean age of 32.5 years. The clinical features include nodular yellowish, rarely red or black concretions (varying with the causative organism) firmly attached to the hair shafts, which may produce a rancid odor and rarely stain the clothes. The associated signs and symptoms include hyperhidrosis (87.5%), hair texture changes (57.1%), and odor (35.7%). The predominant causative agents are Corynebacterium species, isolated in 89.3% of cases.[2] The entire etiologic spectrum is still uncertain, as a large number of organisms are usually present in the concretions. Originally, the infection was linked to "Corynebacterium tenuis," but this term is taxonomically invalid and should be avoided. Recent studies have identified other corynebacteria, such as C. flavescens and C. propinquum, as potential causes of the disease.[3]Serratia marcescens and Dermabacter hominis, skin microbiome species with uncertain pathogenic potentials, have also been implicated.[4] In conjunction with the organisms, several factors, including the rate of apocrine sweat production, its viscosity, the speed of sweat drying, and the rate of hair growth, might contribute to the development of concretions. It has been suggested that the organisms get trapped in apocrine sweat, forming a resilient biofilm around the hair, which may help them evade the host immune system and contribute to the pathogenesis.[5] The closed vault-like anatomy of the axilla might be a contributing factor, potentially explaining why the perineum or scalp is seldom affected.[6] Human apocrine sweat is composed mainly of lipids (60%), of which 76% is cholesterol, and 19% is triglycerides. Normally, this sweat is colorless and odorless, but when acted upon by microorganisms, it undergoes modifications that result in the production of a pungent odor. Corynebacteria produces porphyrins and can split long-chain fatty acids to produce methanethiol, which oxidizes in air to give an offensive odor. Additionally, apocrine sweat contributes to the color of bacterial colonies. However, the significance of apocrine sweat remains enigmatic, as other apocrine sites, apart from the axilla, are less frequently involved. Moreover, the lack of racial predisposition in individuals with higher apocrine gland density, such as blacks, also raises doubts about the role of apocrine glands in this context.[6] As a result, various other predisposing factors, such as obesity, hyperhidrosis, poor local hygiene, humid climates, and male sex, are considered potential contributors to the pathogenesis. Wood's lamp examination reveals pale-yellow fluorescence due to porphyrins. Trichoscopy shows golden-yellow cotton-like concretions adhering to the affected shafts, and close-up trichoscopy may reveal flame-like aspects of nodules and concretions. Few hair shafts feature waxy, yellowish adherent nodules and concretions along the entire length of the hair, which has been described eponymously as the skewer sign, while the presence of a focal pale-yellowish nodule gives rise to the plume sign.[7,8] Ultraviolet-induced fluorescence trichoscopy reveals peripilar yellow–green luminescent concretions.[9] Microscopy of the nodules shows conglomerates of gram-positive pleomorphic bacilli and coccobacilli suggestive of diphtheroids.[10] Definitive diagnosis is established on culture or API Coryne system (standardized system for the identification of Corynebacterium in 24 hours). The differential diagnoses include white piedra, nits, hair casts, and trichorrhexis nodosa [Table 1].[11,12] Treatment includes shaving/trimming the hair, local hygiene, treatment of hyperhidrosis, and application of topical antibiotics (benzoyl peroxide, clindamycin, and erythromycin).Table 1: Trichoscopic features of trichobacteriosis and other differential diagnoses[ 10 ]Malodour from the pubic region can impact sexual life, leading to a partner's reluctance to engage in intimate activities. Embarrassment and fear of judgment create communication barriers, hindering open discussions about the issue. In conclusion, identifying and managing trichobacteriosis pubis causing genital bromhidrosis not only eliminates the malodour but also increases confidence, by reducing embarrassment, leading to improvement in sexual health. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.