Front. Environ. Health Frontiers in Environmental Health Front. Environ. Health 2813-558X Frontiers Media S.A. 10.3389/fenvh.2024.1349268 Environmental Health Original Research The association between interdigital pilonidal sinus and animal groomers is a historical narrative correlation and not a true occupational hazard Al ShenawiHamdi 1 YaghanRami 1 2 Al SaadSuhair 1 BinayfanZiyad M. 3 MohamedYaqoob Y. 3 AlnasserMansour M. 3 Al ShenawiFatima 3 YaghanLamees 4 AlmarabhehAmer 5 AlshammariAbdulrahman 3 Al ShenawiNoor 3 NaguibYahya M. 6 7 * Department of Surgery, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain Department of Surgery, Jordan University of Science and Technology, Irbid, Jordan Medical Student, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain Medical Skills and Simulation Center, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain Department of Family and Community Medicine, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain Physiology Department, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain Clinical Physiology Department, Faculty of Medicine, Menoufia University, Menoufia, Egypt

Edited by: Antonino Maniaci, Kore University of Enna, Italy

Reviewed by: Salvatore Cocuzza, University of Catania, Italy

Salvatore Lavalle, San Raffaele Hospital (IRCCS), Italy

 Correspondence: Yahya M. Naguib yahyamn@agu.edu.bh

Abbreviations PNS, pilonidal sinus.

 05032024 2024 31349268 04122023 20022024 © 2024 Al Shenawi, Yaghan, Al Saad, Binayfan, Mohamed, Alnasser, Al Shenawi, Yaghan, Almarabheh, Alshammari, Al Shenawi and Naguib. 2024Al Shenawi, Yaghan, Al Saad, Binayfan, Mohamed, Alnasser, Al Shenawi, Yaghan, Almarabheh, Alshammari, Al Shenawi and Naguib

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 Introduction

Pilonidal sinus (PNS) is a small hole or “tunnel” in the skin that frequently occurs in the sacrococcygeal region. Nevertheless, PNS has been reported to occur between the fingers (interdigital) in barbers, hairdressers, and animal groomers. The aim of this study was to estimate the prevalence of interdigital PNS among animal handlers in Bahrain and to treat any patients encountered.

 Methods

This is a cross-sectional study with convenience sampling from November 2020 to October 2021. The study participants were animal handlers from stables, veterinary, and pet shops in Bahrain. There were 43 males and 7 females with direct animal contact. 86% of the study population were handling horses, and 15% were handling different types of animals.

 Results

No positive cases of interdigital PNS among participants were found, this might reflect the positive impact of good personal hygiene among our study population. Our study shows that groomers in Bahrain frequently wash their hands after handling animals, and 98% have a daily habit of bathing after work. It was also estimated that 60% of the participants use gloves to handle animals themselves or their waste.

 Discussion

This could be the first study looking at the prevalence of interdigital PNS in animal groomers worldwide. The absence of any case report of interdigital PNS among animal groomers in the recent literature strengthens our assumption that the association between interdigital PNS and hair grooming could be a narrative coincidence rather than a true occupational hazard. The present work may help in better understanding of occupation-disease association, and highlights the importance of mass screening of animal handlers for occupation-dependent health problems.

 pilonidal sinus interdigital animal groomers hair dressers domestic animals Bahrain section-at-acceptanceOccupational Safety and Health Interventions Background

A pilonidal sinus (PNS) is a small hole or “tunnel” in the skin that frequently occurs in the sacrococcygeal region. The word “pilonidal” is derived from the Latin words' pilus (meaning hair) and nidus (meaning nest) (1). Pilonidal sinuses affect about 26 in 100,000 people, with at least 3 times male preponderance (2, 3). Less frequently, PNS was reported in other areas like breast, scalp, and face (2).

Exceptionally, PNS was reported in the interdigital area, with an anecdotal relation to working as a barber, hairdresser, or animal groomer (3–5). Interdigital PNS was first described in 1942 by Templeton and was histologically defined as a foreign body granuloma in a hairdresser (6). Long-standing interdigital PNS induces epidermal down growth, putatively in an attempt to wall off and expel the foreign material, progressing to cyst and sinus formation and predisposing to secondary infection (7).

Eryilmaz et al. proposed a mechanism by which the disease occurs by penetration of hair into the skin. This results in foreign body reactions and the development of a sinus lined by granulation tissue. In contrast to the other types of PNS, interdigital PNS was historically considered an occupational disease among barbers and animal groomers exposed to hair pieces (4).

PNS has been known to manifest as an acute abscess or a chronic sinus with discharge accompanied by recurrent episodes of inflammation (8). Abdulwahid et al. have demonstrated similar presentations of interdigital PNS, with chronic, painful discharging sinus being the most common manifestation (9). Other less common presentations include cystic-like lesions and nodules (4).

The first reported case of an interdigital PNS in animal groomers was in 1951 by Matheson (10). Since then, few reports have appeared in the literature. This condition was identified as an occupational hazard in male hairdressers, sheep shearers, dog groomers, and cow milkers (8). Many reports have demonstrated that interdigital PNS occurred mainly in the third, fourth, and second web spaces (4).

The association between interdigital PNS and hair grooming might be anecdotal, and the recent literature lacks such case reports. Given the improved hygiene over time, this study aimed to estimate the prevalence of interdigital PNS among animal handlers in Bahrain, if any, and treat any encountered patients. We also provided a review of the related literature.

 Materials and methods Ethical considerations

Ethical approval was obtained from the Research and Ethics committee at the Arabian Gulf University (approval number: E031-PI-4/19). Written informed consent was sought from all participants before enrolment.

 Study design

An analytical cross-sectional study was conducted to estimate the prevalence of interdigital pilonidal sinus among animal handlers in the Kingdom of Bahrain. Data were collected during the period of November 2020 and October 2021 by face-to-face structured interviews using a questionnaire. The structured questionnaire was used to measure the socio-demographic characteristics, type of animal handled, use of gloves, washing hands, bathing after work, and Interdigital pilonidal sinus present.

 Study participants, setting and data collection

The target study population included animal handlers from stables, veterinary, and pet shops in the kingdom of Bahrain, who are in direct contact with animals. The research team contacted all the 81 registered animal handlers in Bahrain using Sijilat governmental e-service to assess their willingness to enroll in this study. A representative sample (50 participants) was selected using a convenience sampling technique out of (81) participants (Response rate 62% approximately).

The following variables were collected from the participants: age, gender, hygiene habits, nationality, marital status, ethnicity, cigarette smoking, alcohol ingestion, medical comorbidities (diabetes, hypertension, previous skin diseases), place of work, duration of working with animals (experience), type of work (veterinary, groomer, cleaner, farmer, others), work-related data (dominant hand, types of animals handled). PNS data if they are present (when first noticed, for how long was it there, and if treated before or not). Participants were examined for the presence of interdigital PNS, both by history and physical examination, using a magnifying lens. If any interdigital PNS is encountered, data regarding duration, symptoms, and previous treatment were to be collected.

 Inclusion criteria

Age ≥20 years, with history of direct contact and handling of animals.

 Exclusion criteria

The participants whose ages were less than 20 years, who had contact with only pet animals at home, did not provide informed consent, or refused to participate (31 participants) were excluded.

 Statistical analysis

Data from the survey was loaded into excel sheets (MS Excel) were checked, coded, and then exported to the Statistical Package for Social Sciences (SPSS), version 29 (Chicago, IL, USA) to analyzed. Descriptive statistics analysis was applied to calculate frequencies and percentages and graphically for the categorical variables.

 Literature review

The literature review was performed by searching electronic databases (PubMed and ScienceDirect) and using the following search words: pilonidal sinus, interdigital, groomers, and domestic animals.

 Results

No single case of interdigital PNS was encountered among our study group. Fifty participants (43 males and 7 females) with direct contact with animals were obtained from stables and veterinary and pet shops in the Kingdom of Bahrain. Thirty-one animal groomers refused to participate. Half of the participants were Bahraini. The majority of participants were non-smokers (58%), as well as non-alcohol drinkers (86%), and all participants were right-handed (Table 1).

Demographic data regarding the participants.

Variables Number Percentage (%)
Gender Male 43 86
Female 7 14
Nationality Bahraini 25 50
Non-Bahraini 25 50
Age group 20–40 years 36 72
>40 years 14 28
Cigarette smoking Yes 21 42
No 29 58
Alcohol ingestion Yes 7 14
No 43 86
Experience <5 years 15 30
5–10 years 22 44
>10 years 13 26
Dominant hand Right 50 100
Left 0 0

Regarding the types of animals that groomers handled in this research, 86% were handling horses as the primary animal of care. The second most common animals were cats (Figure 1).

Types of animals handled.

Our study showed that 90% of groomers in Bahrain frequently washed their hands after handling animals, 98% bathed daily after work, and 60% used gloves while handling animals or their wastes (Figure 2).

Hygiene practices among animal groomers.

 Discussion

Twelve isolated cases of interdigital PNS were previously reported among animal groomers (Table 2). The last reports were published in 2020 (7, 11). These twelve cases formed the base of the anectodal relation between working in animal grooming and developing interdigital PNS as a very rare occupational hazard (6, 12). It is postulated that trauma, likely from the repetitive use of the hand as a comb-like device, causes coarse hairs to penetrate the skin of the interdigital crease, subsequently leading to a foreign body reaction, chronic inflammation, and sinus tract formation (4). Studies show that cigarette smoking and alcohol consumption can significantly increase the risk of inflammation and infection (22). Mohanna et al. described a dog groomer who developed a subungual pilonidal sinus complicated by osteomyelitis of the distal phalanx (13).

Literature review.

Authors, year & type of paper History and examination Investigations Treatment & prognosis
Olabi et al. (7), case report 41-year-old, right-handed male pet groomer Presented with 2 small sinuses, over the dorsal aspect and the free margin of the webspace of his right fourth finger. Dermoscopic and histologic examination of the excised tissue Antibiotics course and removed under general anesthesia, with reconstruction of the defect with a local flap. No recurrence after 2 months postoperatively.
Phillips et al. (11), case report Male Shearer Not accessible
Matheson et al. (12), case report 34-year-old, male shearer Recurrent painful swelling in interdigital space between left middle and ring fingers Previous incident at same sight in the right hand Block dissection of affected area in third recurrence. Sinus cavity containing wool with serrated margin lined superficially by squamous epithelium and deeply has connective tissue. Incision and drainage Personal treatment first time by hot foments and spontaneous discharge of pus. Second treatment by hot water and removing wool using tweezer.
Mohanna et al. (13), case report 37-year-old, male dog groomer Presented with recurrent PNS in right thumb, oblique split in the distal pulp tissue, discharging purulent fluid Radiographs showed a destructive lesion involving the tip of the terminal phalanx, consistent with osteomyelitis Collection of hair shafts surrounded by kerati and benign squamous epithelium containing acute and chronic inflammatory cells Surgical excision of the distal half of the terminal phalanx No recurrence for 8 months
Vaiude et al. (14), case report 31-year-old, right-handed male sheepshearer Painful, inflamed middle finger and nodule in the 3rd web space the left hand Hitsology: The dermis contains an inflamed pilonidal sinus with evidence of ulceration. The sinus revealed sheep hair. Erythromycin followed by Surgical excision with primary closure with a local skin flap. One recurrence in 2 months
Ramilo et al. (15), case report 24-year-old, left-handed male dog groomer Third interdigital space of his dominant hand Histopathologic examination: An acanthotic, hyperplastic epidermis with scale crust, and nodular dermal infiltrates composed of epithelioid histiocytes, plasma cells, lymphocytes, and eosinophils. Transepidermal extrusion of polarizable hair cortical material Sinusotomy and debridement with healing by secondary intention followed by proper wound care. No evidence of recurrence 3 years after resection
Meneghini et al. (16), case report Milker Not accessible
Sloan et al. (17), case report 55-year-old, male abattoir worker Pain and swollen third web space of left hand. Ultrasound showed a hypoechoic area consistent with chronic inflammation and a linear hyperechoic structure measuring 4.25 mm The lesion was explored under local anaesthesia and excised completely. No recurrence after 6 weeks.
Shikowitz-Behr et al. (18), case report 24-year-old, male dog groomer Second web space of his right hand revealed a 0.8 cm abscesses Histological examination: A cystic follicle with surrounding fibrosis and focal hemosiderin Incision and drainage and complete antibiotic course 4 weeks later, with recurrent abscess at the same location.
Papa et al. (19), case report 47-year-old, female dog groomer Tender erythematous 1.5 cm nodule in fourth web space of left hand with central pustule Elliptical biopsy sent for histopathologic examination: purulent drainage cultured for microorganisms. Subcorneal cystic space containing neutrophils surrounding fragment of hair and portion of epidermis absent. Gram stain showed gram positive cocci. Hairs were removed from cavity. Prescribed cephalexin. Patient returned after 1 month with tenderness and drainage; remaining sinus and tissue containing hair excised and prescribed cephalexin again. Healed and no recurrence.
Ito et al. (20), case report 24-year-old, female dog groomer Fourth web space of the right hand showed a red nodule, 8 mm in diameter, near the fistula, multiple hairs of different colors were seen in the fistula Culture and histopathological examination: multiple hair shafts surrounded by infiltration of inflammatory cells with keratin and squamous epithelium with some foreign body giant cells Treated with cefcapene Pivoxil of 300 mg/day for 7 days and surgical excision was performed. No recurrence occurred
Stern et al. (21), case report 39-year-old, female animal groomer Web between the middle and ring fingers of one hand small sinus tract with visible hair and an area of chronic inflammation. An area of chronic inflammatory tissue with a sinus tract and multiple visible hairs Pathological examination: Sinus tract with abundant keratin, epidermal thickening, dermal fibrosis with chronic inflammation, and multiple embedded hairs History of treatment with antibiotics therapy, drainage, and surgical excision of the sinus No recurrence

We did not encounter any cases of interdigital PNS among our study group. This could result from the small number of participants, but it also might reflect that the assumed historical causal relationship between animal grooming and the risk of developing interdigital PNS was exaggerated in the literature. The improved hygiene practices over the decade might have helped in reducing this hazard. It is worth mentioning here, however, that we do not have any firm evidence from the literature that PNS occurrence in other sites of the body is related to the level of hygiene practice.

In our study, 98% of participants bathed after work, 90% washed their hands regularly, and 60% used gloves. These measures may be a contributing factor in reducing the amount of recent literature on the association between interdigital PNS and animal grooming. Dupuis et al. showed that poor hygiene might cause multiple health issues and different types of infections (14). To the best of our knowledge, there is no data regarding the input of using gloves on the reduction or abolishment of the occurrence of interdigital PNS.

Our literature review showed that conservative approaches such as removal of hairs from the sinus, drainage of abscesses, and antibiotic administration are inadequate treatments for interdigital PNS. Most authors agree that radical surgical excision of the involved tissue allowing for secondary healing, is curative (5, 23) (Table 2).

Treatment considerations include cost, healing period, scar tissue formation, and recurrence, with the latter being the most significant (8). Flap repairs can reduce the duration of recovery and, therefore, the away from work time (4). The recurrence was higher among patients treated with incision and drainage compared to those treated with radical excision (4).

In the Arabian Gulf region, horse stables are popular; thus, the number of animal groomers dealing with horses was the highest in our study.

Further research should be done to explore the relationship between good personal hygiene practices and the occurrence of interdigital PNS in groomers. Our study was conducted during the COVID-19 pandemic when Bahrain had strict regulations about hygiene practices and sanitization. In addition, the government of Bahrain has strict supervision and monitoring over stables and animal shops to prevent the spread of diseases. These factors support the findings of our studies that the high levels of hygiene practices might have led to abolished interdigital PNS cases among hair groomers in Bahrain.

Limitations

Although statistically sound, the number of animal groomers in the Kingdom of Bahrain remains low due to the limited number of pet and veterinary shops and horse stables. The number of participants was further affected by the fear of the animal groomers that participating in the study might jeopardize their jobs. Future work could extend to involve house-based animal grooming and compare whether the compliance of animal groomers to hygiene protocols is fundamental in the protection against PNS in house or work settings.

 Conclusion

This could be the first study which looks at the prevalence of interdigital PNS in animal groomers worldwide. Our study did not document the presence of any interdigital PNS among animal hair groomers in Bahrain. This might reflect the positive impact of good personal hygiene in the prevention of interdigital PNS. However, together with the absence of any case reports of interdigital PNS among hair groomers in the recent literature, our findings might suggest that the association between interdigital PNS and animal hair grooming could be a narrative coincidence rather than a true occupational hazard. This study could improve our knowledge about occupation-disease association.

 Data availability statement

The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author.

 Ethics statement

The studies involving humans were approved by Research and Ethics Committee at Arabian Gulf University (E031-PI-4/19). The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

 Author contributions

HA: Conceptualization, Investigation, Methodology, Project administration, Supervision, Validation, Writing – original draft, Writing – review & editing. RY: Conceptualization, Data curation, Supervision, Validation, Writing – review & editing. SA: Conceptualization, Validation, Writing – review & editing. ZB: Data curation, Writing – review & editing. YM: Data curation, Writing – review & editing. MA: Data curation, Writing – review & editing. FA: Data curation, Writing – review & editing. LY: Data curation, Formal Analysis, Writing – review & editing. AA: Data curation, Formal Analysis, Methodology, Software, Validation, Writing – review & editing. AA: Data curation, Writing – review & editing. NA: Conceptualization, Data curation, Formal Analysis, Methodology, Writing – review & editing. YN: Conceptualization, Project administration, Supervision, Writing – review & editing.

 Funding

The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article.

 Acknowledgment

Special thanks to College of Medicine and Medical Sciences at Arabian Gulf University.

 Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

 Publisher's note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

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