Pediatric middle ear actinomycosis: report of two cases

Introduction

Actinomyces is an anaerobic, Gram-positive, filamentous, and branching rod-shaped bacterium that is considered part of the normal flora of the oropharynx, gastrointestinal tract, and genital tract in humans. However, it can cause an infection known as actinomycosis, with Actinomyces israelii (A. israelii) being the most common pathogenic organism (1,2). A. israelii causes an infection when the mucosal barrier is compromised mainly due to minor trauma, diseased mucosa or a decline in the host’s immune system, typically due to another pathogen. This microaerophilic microorganism can be diagnosed through isolated culture that should be placed immediately under anaerobic conditions, which reveals the presence of yellow sulfur granules. A more sensitive test is Gram staining, in which a positive Gram stain is diagnostic with a morphology for filamentous branching rods (1,2). Actinomycosis can present as a chronic granulomatous abscess as a result of a chronic suppurative granulomatous infection (1,2). The most commonly reported site is the cervicofacial region due to dental infection; other sites include the thoracic, abdominal, and pelvic regions. Actinomycosis of the middle ear and temporal bone is a known cause of this condition. It is hypothesized that actinomycosis typically occurs due to dissemination through the eustachian tube from the nasopharynx to the middle ear and mastoid cavity and presents as a chronic suppurative infection (3). Treatment should commence as soon as actinomycosis is diagnosed. The recommended treatment usually includes surgical debridement and a prolonged course of oral antibiotics sensitive to A. israelii, such as beta-lactams (3,4).

Only approximately 50 cases have been reported in the English literature worldwide (3,4). Locally, only one case has been reported in Jeddah, Saudi Arabia in 2018 (5). The lack of familiarity with actinomycosis of the middle ear delays diagnosis and proper management. To better understand actinomycosis and its possible predisposing factors and presentations, we report two pediatric cases of actinomycosis in the middle ear presenting as chronic suppurative otitis media (CSOM), one of which had ventilation tubes (VT) inserted. The two cases were resistant to standard management of CSOM at first, which entailed a deeper look into the possible causes. The first case was in a syndromic child with a VT, which signifies possible predisposing factors. We present this article in accordance with the CARE reporting checklist (available at https://acr.amegroups.com/article/view/10.21037/acr-2026-0046/rc).

Case presentation

Case 1

A 7-year-old boy with Joubert syndrome and a history of hypotonia, gastroesophageal reflux disease, and atopic dermatitis underwent adenoidectomy with bilateral VT insertion for bilateral chronic serous otitis media. The patient complained of persistent otorrhea in the right ear that started 6 months after VT insertion and was referred to the otology clinic after failed treatment of the infection. The patient had multiple courses of topical ofloxacin and short courses of Augmentin and clindamycin with no improvement for 2 months. After that examination revealed thick yellowish secretion and granulation tissue covering the tympanic membrane. The VT was not seen. There was a greenish hue material in the middle ear raising the suspicion of a dislocated VT inside the middle ear. The decision was then made to proceed with an endoscopic middle ear exploration. Intraoperative findings showed a bulging tympanic membrane with thick greenish material retrieved from the middle ear (Figure 1A). The middle ear mucosa was severely inflamed, with the presence of a greenish substance, granulation tissue, and adhesions (Figure 1B). The thick green substance and granulation were cleared and biopsied for further investigation, and myringotomy was performed anteriorly. The histopathological analysis report was consistent with the diagnosis of actinomycosis, showing filamentous branching organisms. During the postoperative visit, examination of the right ear revealed bulging of the tympanic membrane with effusion. Temporal bone computed tomography (CT) revealed a soft tissue lesion occupying the epitympanum, mesotympanum, and hypotympanum, with subsequent extension into Prussak’s space and complete opacification of sclerotic mastoid air cells (Figure 2A). Ossicular erosion with mild blunting of the scutum was also observed (Figure 2B). After consulting our colleagues in the Infectious Disease Department, an agreement for another surgical exploration was reached. The Rationale behind the revision was made to eradicate the remaining disease noted on post-op follow-up and to obtain more cultures to confirm diagnosis. Intraoperatively, the middle ear mucosa exhibited inflammation with granulation tissue. Cultures and biopsies, including for tuberculosis, were also performed. The second pathology and culture results were also negative. The patient was administered amoxicillin-clavulanic acid extended-release for 3 months by the infectious diseases department, with regular follow-up visits every 6 months with the Pediatric Ear, Nose, and Throat (ENT) Department. Microscopic examination of the ear during the visits was clear, with no recurrence observed during the follow-up period of 2 years.

Figure 1 Intra-operative endoscopic view of tympanic membrane and middle ear cavity. (A) Thick discharge from a bulging tympanic membrane. (B) Inflamed middle ear mucosa.

Figure 2 Pre-operative temporal bone CT imaging. (A) Axial cut of temporal bone CT showing soft tissue occupying the middle ear with opacified sclerotic mastoid air cells. The arrows pointed at opacified sclerotic mastoid air cells and soft tissue opacification at middle ear. (B) Coronal cut of temporal bone CT showing soft tissue occupying middle ear with blunting of scutum. The arrow pointed at scutum showing blunting. CT, computed tomography.

Case 2

A 10-year-old healthy girl presented to our clinic with a 4-month history of left otorrhea, otalgia, and hearing loss. She was prescribed a short course of oral augmentin and topical ofloxacin for 2 months; however, no improvement was observed. One culture showed Staphylococcus aureus, but subsequent cultures were negative. Upon examination, the external auditory canal was filled with pus, accompanied by a polyp and granulation tissue. Audiometric examination revealed moderate conductive hearing loss in the left ear. Temporal bone scanning revealed complete opacification of the left external auditory canal, middle ear cavity, and mastoid air cells without bony erosion (Figure 3). The patient underwent endoscopic middle ear exploration, tympanoplasty, and limited atticotomy of the left ear. Intraoperative findings revealed that the inflammatory polyp originated from the middle ear (Figure 4A). The middle ear was filled with thick greenish material, in addition to severely inflamed mucosa (Figure 4B). Endoscopic limited atticotomy was performed, and all the granulation tissue and debris were removed. Limited atticotomy was enough to visualize and remove all the disease. No keratin debris was noted intra-operatively. Irrigation through the antrum was performed to clear as much disease as possible from the mastoid. There was no cholesteatoma, and the ossicular chain remained intact. Cartilage tympanoplasty was then performed. Histopathological analysis revealed an inflammatory otic polyp with the presence of Actinomyces branching filaments surrounding it. The patient was started on oral Augmentin extended release for 3 months, based on infectious disease recommendations. The patient was followed up with the Pediatric ENT Department every 6 months with clear microscopic examination and well-taken graft. No relapse was observed during the follow-up period of 18 months.

Figure 3 Axial cut of temporal bone CT of the left ear showing opacification of external auditory canal, middle ear and mastoid air cells. Arrows pointing to mastoid air cells and middle ear showing opacification. CT, computed tomography.

Figure 4 Intra-operative endoscopic view of middle ear cavity. (A) Intraoperative examination showing inflammatory polyp. (B) Thick greenish discharge originating from middle ear.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patients’ families for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

Actinomycosis is a rare middle ear infection. A. israelii constitutes the commensal flora of the oropharynx; hence, it is proposed that infection most likely is a result of seeding from nasopharynx through the eustachian tube. Other postulated mechanisms include direct infection through the external auditory canal or hematogenous routes (6). In the present cases, both patients were immunocompetent. However, one patient had a history of VT insertion, making both hypotheses possible, although seeding from the nasopharynx is the most likely mechanism.

Actinomycosis is a chronic, indolent, and recurrent infection that is difficult to detect (1,2). Middle ear actinomycosis typically presents with intermittent otorrhea, hearing loss, and mild otalgia that are resistant to antibiotic treatment, leading to delays in diagnosis (7). Differential diagnoses include atypical infection and cholesteatoma. Complications can occur through direct extension, leading to osteomyelitis (8). However, similar to recent literature, our cases presented with CSOM without local or intracranial complications. Physical examination usually reveals discharge, granulation tissue, polyps, and perforated tympanic membranes (3,5). Other diagnostic aids include CT. Although it has no specific diagnostic feature of actinomycosis, it is important to delineate the extent of the disease and to rule out complications and other causes of chronic ear discharge (7,8).

Isolating Actinomyces species from surgical specimen cultures is the gold standard diagnostic method; however, approximately 70% of these cultures are negative (5).

The challenge in diagnosing actinomycosis lies in the isolation of the organism, mainly because of two issues: first, A. israelii rarely occurs alone and is mainly present with other pathogens. Up to 5–10 organisms can coexist with A. israelii, which is usually referred to as a polymicrobial infection; second, because it is a commensal organism, it is difficult to determine whether it is an offending or an inhabitant organism. Thus, obtaining a culture from a sterile site is key to reaching a diagnosis, especially if pathognomonic yellow sulfur granules are present. However, culturing A. israelii takes 10 days, and it may fail if antibiotics are recently administered. Therefore, if clinically suspected, early testing should be performed. A more sensitive method for diagnosis is histological examination, where the presence of filamentous organisms with sulfur granules is highly suggestive of actinomycosis (1,2,4).

Combined surgery and long-term antibiotic therapy are the treatments of choice for actinomycotic otomastoiditis. Owing to the anaerobic nature of actinomycosis, mechanical debridement by surgery may be required to aerate all tympanomastoid surfaces to reduce the bacterial load. The benefits of surgery must be reinforced by the use of long-term antibiotics (7).

Fortunately, A. israelii can be eradicated using beta-lactams. Clindamycin is a suitable alternative for patients with penicillin allergy (1). The duration of treatment documented in the literature varies from 6 weeks to 6 months (3,4). In our case, using amoxicillin-clavulanic acid for 3 months period was sufficient to achieve complete recovery.

In our case report, both cases presented as persistent resistant otorrhea that required surgical intervention for proper diagnosis and management similar to the reported studies in the literature review of Kullar et al. (4). Moreover, in the review pediatric cases ranged from 6 to 14 years old which lies within the same age bracket of our reported cases. Surgical intervention for the pediatric cases previously mostly required mastoidectomy, however, in our case report our surgical intervention was limited to endoscopic atticotomy and middle ear exploration. Long-term antibiotics eradicated the disease.

Conclusions

Although middle ear actinomycosis is rare, it should be considered as a differential diagnosis for CSOM, especially if it is refractory to treatment with negative culture. Middle ear actinomycosis can be one of the differential diagnoses of post tympanostomy tube otorrhea.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://acr.amegroups.com/article/view/10.21037/acr-2026-0046/rc

Peer Review File: Available at https://acr.amegroups.com/article/view/10.21037/acr-2026-0046/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-2026-0046/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patients’ families for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Sharma S, Hashmi MF, Valentino III DJ. Actinomycosis. 2023 Aug 7. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2026 Jan–.
2. Valour F, Sénéchal A, Dupieux C, et al. Actinomycosis: etiology, clinical features, diagnosis, treatment, and management. Infect Drug Resist 2014;7:183-97. [Crossref] [PubMed]
3. Olson TS, Seid AB, Pransky SM. Actinomycosis of the middle ear. Int J Pediatr Otorhinolaryngol 1989;17:51-5. [Crossref] [PubMed]
4. Kullar PJ, Yates P. Actinomycosis of the middle ear. J Laryngol Otol 2013;127:712-5. [Crossref] [PubMed]
5. Sheikh MA, Alenzi S, Ahmadi AA, et al. Actinomycosis of the Middle Ear and Mastoid. Med Arch 2018;72:295-6. [Crossref] [PubMed]
6. Ajal M, Turner J, Fagan P, et al. Actinomycosis oto-mastoiditis. J Laryngol Otol 1997;111:1069-71. [Crossref] [PubMed]
7. Gazzano E, Chanteret C, Duvillard C, et al. A case of actinomycosis of the middle ear and a review of the literature. International Journal of Pediatric Otorhinolaryngology Extra 2010;5:70-3.
8. Sobol SE, Samadi DS, Wetmore RF. Actinomycosis of the temporal bone: a report of a case. Ear Nose Throat J 2004;83:327-9.