Kerion of the pubis and vulva with bacterial superinfection: a rare occurrence

Abstract

Kerion is a severe hypersensitivity reaction to fungal infection that is rarely seen in the groin. Frequent shaving of pubic hair and religious conservatism surrounding genital hygiene are common among Bedouin women in the Negev Desert, and may predispose to kerion. This case highlights the clinical course of a 20-year-old Bedouin woman who presented with severe kerion celsi of the pubis and vulva with secondary bacterial infection. The patient was successfully treated with intravenous antibiotics, oral antifungal medication and wet topical dressings. The case outlines the risk factors and treatment for severe kerion celsi of the groin, as well as possible preventive measures that may reduce its incidence.

Background

Kerion is a severe inflammatory reaction to dermatophyte infection.¹ It is most commonly seen as a complication of tinea capitis infection among paediatric patients, and is associated with poor hygiene, exposure to animals and low socioeconomic status.² The clinical presentation of dermatophyte infections is diverse, ranging from transient and non-specific symptoms, to extremely painful, destructive pustular lesions that may result in irreversible alopecia. These pustular lesions, seen in kerion formation, are due to a delayed-type hypersensitivity reaction to the dermatophyte infection. While infection is most commonly seen in the scalp, it can occur anywhere on the body, further complicating the diagnosis.³ Delayed diagnosis of a dermatophyte infection increases the risk of severe presentation and kerion formation. Unfortunately, the diagnosis of kerion is often only reached after antibiotic therapy fails.⁴ A recent Cochrane review found weight-adjusted terbinafine (10–20 kg: 62.5 mg/kg/day; 20–40 kg: 125 mg/kg/day; >40 kg: 250 mg/kg/day for 2–4 weeks) or fluconazole (loading dose of 6–12 mg/kg/day followed by 3–6 mg/kg/day for 2–4 weeks) to be as effective as the standard griseofulvin (10–25 mg/kg/day for 6–8 weeks) treatment regimen in managing Trichophyton infections such as kerion celsi.³

Kerion celsi of the vulva is rare. Reported cases show geographical diversity of the condition, but all reports identified Trichophyton mentagrophytes as the causative fungal agent, and many patients had recently shaved the pubic area.^5–8 Diagnosis typically requires fungal culture or skin biopsy with periodic acid-Schiff (PAS) staining, as potassium hydroxide (KOH) prep scrapings may not identify the causative organism of deep infections.⁸ Kerion celsi is more likely to develop in the absence of prompt medical care. Religion, personal preference and limited medical knowledge may all delay a patient from seeking medical care. Delayed intervention coupled with the diagnostic challenge posed by kerion celsi of the vulva may increase the risk of morbidity from this disease.^{7 8}

Case presentation

A 20-year-old Bedouin woman with no known significant medical history presented to the emergency department with a 2-week history of painful swelling and exudative rash in her groin. There was no recent trauma to the area, but she had shaved her groin the week before the rash appeared. She was not sexually active within the past year and denied systemic symptoms. She did not recall recent contact with pets and other animals, but endorsed living in a community with many animals in the area. The patient did not seek treatment at the onset of symptoms, despite experiencing severe discomfort, due to religious beliefs and reluctance to disclose sensitive health information out of fear that rumours about her condition would spread back to her community. She assumed the illness would pass on its own, and sought treatment from her local family care physician when there was no symptom improvement for over a week. She was prescribed amoxicillin-clavulanate (875 mg orally every 12 hours) and fusidic acid (topical cream every 24 hours) for suspected bacterial folliculitis. After 1 week of therapy, there was no improvement in symptoms and the patient was referred to the emergency department.

Physical examination revealed an uncomfortable patient with an erythematous, pustular, carbuncle-like rash involving the pubis, labia majora and upper thighs (figure 1). The patient was afebrile. Initial laboratory investigations included viral PCR and bacterial culture for suspected herpes simplex virus (HSV) infection with bacterial superinfection. While awaiting the results of these tests, the patient was started on clindamycin (600 mg intravenously every 8 hours) and ciprofloxacin (500 mg orally every 12 hours). The lesion was found to be negative for HSV by PCR, and bacterial culture was positive for Pseudomonas aeruginosa and Klebsiella species. After 3 days of therapy, several satellite lesions appeared on the anterior and inner thighs. Severe candida infection was suspected, and fluconazole (450 mg orally every 24 hours) was added to the treatment regimen. A punch biopsy was taken (figure 2). PAS stain was negative, but fungal hyphae were present, so terbinafine (250 mg orally every 24 hours) and betamethasone (topical cream every 24 hours) therapy was added. Fungal culture taken at this time was positive for T. mentagrophytes, and punch biopsy revealed fibrinopurulent exudate with inflamed granulation tissue, focal foreign body giant cell reaction and focal fat necrosis. At this time, 5 days into hospitalisation and nearly 3 weeks after the onset of symptoms, the patient was diagnosed with kerion celsi of the vulva with secondary bacterial folliculitis.

Figure 1.

Erythematous, pustular rash with satellite lesions seen on presentation to the emergency department.

Figure 2.

Punch biopsy findings of fibrinopurulent exudate with inflamed granulation tissue and focal giant cell reaction (arrow) with fat necrosis.

In total, the patient received a 7-day course of antibiotics and a 6-day course of fluconazole, as well as 2 months of terbinafine and betamethasone. Her symptoms began to improve on day 9 of hospitalisation, after she had completed the full courses of antibiotic and fluconazole therapy. The patient was hospitalised for a total of 18 days. At discharge, the patient reported full resolution of symptoms, and there was no lasting clinical evidence of disease. Resolution of disease was confirmed at a follow-up appointment 5 weeks after discharge, and all therapies were stopped. There was no residual scarring, and the patient was pleased with her clinical outcome.

Global health problem list

• Shaving of the genital region is a common practice in many cultures and religions, and may predispose to the development of kerion celsi. This practice is common among religious groups in Israel; of the six published reports of kerion celsi of the vulva, this is the second to occur in Israel.

• Patients may be reluctant to seek care for genital conditions due to cultural conservatism and limited medical knowledge.

• The diagnosis of vulvar kerion celsi is clinically difficult due to non-specific symptoms and rarity of presentation in the vulval and pubic areas. Delay in diagnosis leads to increased morbidity from this condition.

Global health problem analysis

Pubic hair removal is common to many cultures around the world.^{9 10} Most women engage in this practice at some point during their lives, with higher rates observed in certain cultural and religious groups.^11–13 Shaving the genital region is associated with numerous morbidities, including both minor insults (epidermal abrasion, ingrown hairs) and more severe conditions that require medical care (folliculitis).¹⁴ It is important to note that all five of the previously reported cases of vulvar kerion were associated with a recent history of shaving the genital region.^{5–8 15} This is a significant source of potential morbidity for patients, and physicians should take care to discuss these risks in a way that is sensitive and culturally appropriate. Community health education programmes that discuss genital hygiene at the onset of puberty may also be useful in promoting safe hygiene practices.

To provide culturally appropriate counselling, physicians must understand which patients remove their pubic hair and why. Body hair removal is associated with good hygiene in Islamic traditions, and both shaving and waxing are common among Bedouin women and are seen as hygienic behaviours. There is social pressure to remove pubic hair as well.¹⁶ Israel has significant Muslim and Jewish religious communities, and it is interesting to note that this is the second reported case of vulvar kerion in a self-identified religious woman in Israel. There is evidence of low health resource utilisation for gynaecological complaints in Israel, in spite of universal health insurance coverage and readily accessible community clinics that eliminate predictable financial disparities in healthcare.¹⁷ This suggests social barriers to receiving care. Gynaecological complaints are often assumed to be related to sexual behaviour, particularly among insular religious communities, and it is logical that women, especially unmarried women like the patient in this case, may choose to avoid care rather than exposing themselves to potential criticism for sexual promiscuity, which can result in social isolation. Counselling patients to avoid pubic hair removal is unlikely to be effective when it is a culturally rooted practice. However, healthcare providers can promote safer mechanisms such as using hair trimmers or laser hair removal in lieu of shaving, with hair trimmers being a particularly cost-effective alternative.

To date, every reported case of vulvar kerion and many reported cases of kerion in other anatomical sites indicate a clinical course complicated by initial misdiagnosis and subsequent delay in treatment. This may be due to a number of factors, including non-specific signs and symptoms, as well as low clinical suspicion of kerion in unusual anatomical sites. It is important to note that misdiagnosis often occurs because patients present at a late stage of the disease, at which point the fungal infection is so severe that it produces pustular exudative changes more characteristic of bacterial infection.^{15 18–20} Thus, physicians should have a high index of clinical suspicion for fungal infection when patients present with what appears to be folliculitis and a recent history of shaving the groin. Higher clinical suspicion will result in earlier targeted diagnostic testing with fungal culture and punch biopsy, ultimately leading to faster treatment, and ideally more rapid resolution of the disease.

Learning points.

• Kerion is an extreme inflammatory T cell-mediated response to dermatophyte infection, and its nodulopustular presentation can readily be mistaken for bacterial folliculitis, but it will not respond to antibacterial therapy.

• The vulva is an exceedingly rare site for kerion celsi; to date, only five cases have been published in the literature.

• The limited literature suggests that kerion celsi of the vulva may be related to recent contact with animals and recent shaving of the groin.

• Clinical suspicion for kerion should be high in cases of suspected bacterial folliculitis.

• Healthcare providers may help combat the incidence of vulvar kerion by promoting genital hygiene and encouraging patients to seek prompt medical care for signs of infection.