Sensorineural Hearing Loss (chronic) and Sudden Hearing Loss
No randomized trial was found; a few small reports without described randomization or blinding mention less ear noise and some hearing gain in chronic loss. Sudden hearing loss is an emergency: urgent ENT care comes first, and leeches must never delay it.
Patient Summary
- Is this FDA-cleared for this use?
- No. The FDA cleared medicinal leeches in 2004 only for venous congestion in microsurgical reconstruction (K040187). Use for hearing loss is not FDA-evaluated.
- What evidence exists?
- There is no randomized trial. A few small studies, mostly from Russia and Ukraine, compared patients given leeches plus medicine with patients given medicine alone; their authors report less ear noise and some hearing gain, but none describes randomization or blinding and the results have not been confirmed. No study tested leeches for sudden hearing loss. Hair cells lost from the inner ear do not grow back, and no human study shows that leeches bring them back. For chronic hearing loss the established care is a hearing test and hearing aids, or a cochlear implant for severe loss. Sudden hearing loss needs urgent medical care first.
- Main risks
- Delaying urgent evaluation and treatment of sudden hearing loss, which may reduce the chance that hearing recovers
- Bleeding and oozing from each bite site for several hours, sometimes up to 24 hours
- Itching, redness, and irritation at the bite sites lasting days to weeks
- Mild anemia if many leeches are used
- Local skin infection or, rarely, Aeromonas infection from leech gut bacteria
- Allergic reaction to leech saliva (uncommon)
- Spending time and money on leeches instead of proven help such as hearing aids
- Small bite marks that usually fade over weeks to months (rarely a pale spot stays longer)
- Who should not consider this
- Anyone whose hearing dropped suddenly and who has not yet been seen urgently by an ear, nose and throat (ENT) clinician
- Anyone whose hearing loss has not yet been checked with a hearing test (audiogram)
- Patients taking blood thinners such as warfarin, apixaban, rivaroxaban, dabigatran, or heparin
- Patients with hemophilia or other inherited bleeding disorders
- Patients with anemia
- Patients with a weakened immune system, especially during chemotherapy
- Patients with hearing loss in one ear only, or clearly worse in one ear, who have not had a hearing test and MRI or brainstem test
- Patients with hearing loss together with vertigo, facial weakness, ear pain with blisters, or ear discharge, or with repeated sudden episodes or sudden loss in both ears, until a doctor has checked them
- Patients with an ear infection, a draining ear, a known eardrum perforation, a cochlear implant or other hearing implant, or recent ear surgery
- Patients with severe hearing loss in the only hearing ear
- Pregnant patients (leech therapy is not done during pregnancy)
- What to ask your clinician
- Has my hearing been tested with an audiogram, and is my loss sudden, one-sided, or getting worse?
- Do I need an MRI or another test to rule out a problem with the hearing nerve?
- If my hearing dropped suddenly, should treatment start right away, and which treatment?
- Would hearing aids or a cochlear implant help me, and have I seen an audiologist?
- Am I taking any medicine that can harm hearing?
- What evidence is there for leeches in hearing loss, and what would I delay or give up by trying them?
- Are leeches from an FDA-registered supplier and used only once, and what is the plan for bleeding and Aeromonas infection?
- When to seek urgent care
- Hearing that drops suddenly in one or both ears: get medical care as soon as possible (emergency department or urgent ENT visit); do not wait or try other treatments first
- Hearing loss with vertigo or severe dizziness, facial weakness or drooping, double vision, trouble speaking, or numbness or weakness (call 911)
- Ear pain with blisters in or around the ear, or ear discharge with fever
- Bleeding from a bite site lasting more than 24 hours or soaking through dressings
- Spreading redness, warmth, pus, red streaks, or increasing pain around the bite sites
- Hives, facial or tongue swelling, throat tightness, or breathing difficulty
What this does NOT mean
- It does not mean leech therapy is FDA-cleared for hearing loss — it is not.
- It does not mean leeches treat sudden hearing loss. A reference book says leech therapy can be considered while stating that no study data existed; that is not evidence that it works.
- It does not mean leeches can restore lost hearing — hair cells lost from the inner ear do not grow back, and no human study shows that leeches change this.
- It does not mean improving blood flow to the inner ear is a proven approach — the American guideline for sudden hearing loss advises against routinely prescribing vasodilators, thrombolytics, or other vasoactive drugs.
- It does not mean small Russian or Ukrainian reports without described randomization or blinding, or a monograph summary of a dissertation, are reliable proof.
- It does not replace an urgent ENT visit, a hearing test, hearing aids, or a cochlear implant.
Safety cross-references
Clinical Profile
- Category
- ENT
- ICD-10
- H90.3, H90.41, H90.42, H90.5, H91.20, H91.21, H91.22, H91.23, H91.10, H91.11, H91.12, H91.13
- Safety tier
- High
Evidence Summary
No randomized controlled trial of leech therapy for sensorineural hearing loss was identified in PubMed or in the two reference books. The human evidence is a few small reports, mostly Russian or Ukrainian, in which randomization and blinding are not described. Senchukova and Nikulina (2013, Fundamental'nye Issledovaniya; not indexed in PubMed) added leeches to drug therapy in 38 patients with vascular sensorineural hearing loss and marked tinnitus and compared them with 35 given drug therapy alone; the authors report more tinnitus relief and a larger hearing gain with leeches, but randomization, blinding and adverse events are not described. Zabolotnyi and Mishchanchuk (2019; PMID 31841493) report a positive effect on hearing in 59 of 68 male Chornobyl clean-up workers with premature age-related hearing loss treated with leeches versus 45 of 61 given drug treatment; the groups were selected from archive data and no randomization or blinding is described. Morozova and Aksenova (2009; PMID 19738593, Russian-language) reported less ear noise in vascular cochleovestibular disorders; the abstract gives no numbers or design details. The Baskova and Isakhanyan monograph (2004) summarizes a candidate dissertation on 104 patients with chronic sensorineural hearing loss (Zhuravsky, 2000) and states that leech therapy was accompanied by a therapeutic effect in loss of vascular and neurogenic origin, improved speech understanding without changing hearing thresholds in age-related loss, and gave only non-specific stabilizing support in ototoxic and post-infectious loss; the monograph gives no comparison data for these statements, and it also cites animal work on inner-ear structures that has not been shown in humans. Michalsen, Roth and Dobos (2007) state that leech therapy can be considered for sudden hearing loss although no scientific study data had been published. Lost inner-ear hair cells do not regenerate in humans (PMID 37957052), and no human study shows that leech therapy restores them. Sudden sensorineural hearing loss is a medical emergency: urgent ENT evaluation, a hearing test and a discussion of standard treatment options come first (AAO-HNSF guideline, PMID 31369359), and leech therapy must never delay them. Hearing aids and, for severe loss, cochlear implants are the established care for chronic loss.
What the books describe
Below is a summary of what books on hirudotherapy say about this condition. These are the authors’ observations, not a proven effect and not a promise of results. Hirudotherapy has contraindications; the decision is made by a physician.
- Baskova and Isakhanyan name chronic sensorineural hearing loss (a lasting reduction of hearing due to damage to the inner ear or the auditory nerve) among the conditions in which hirudotherapy is mainly used in ENT practice[B1].
- They retell the dissertation of Zhuravsky (2000): 104 patients with chronic sensorineural hearing loss were examined clinically and audiologically; according to the author’s conclusions, in patients with hearing loss of vascular and neurogenic origin hirudotherapy is accompanied by a therapeutic effect, and in secondary hearing loss against the background of chronic inflammation of the middle ear a reduction of the conductive and sensorineural components is achieved[B1].
- In age-related hearing loss, according to the same conclusions, hirudotherapy led to improved speech intelligibility without affecting hearing thresholds (that is, the quietest sounds a person can hear); in hearing loss caused by medicines that damage the ear and after past infections, the result was, as stated, “a nonspecific supportive effect aimed at stabilizing the remaining process”[B1].
- In retelling the dissertation, Baskova and Isakhanyan name neither a comparison group, nor numerical results (for example, the change in hearing thresholds), nor the number of patients in the subgroups, so from this retelling it is impossible to judge how large the effect is or whether it was compared with anything[B1].
- They quote Zhuravsky and co-authors (1997) as saying that hirudotherapy in chronic sensorineural hearing loss had been discussed in the literature only in connection with correcting noises in the ear, and they retell material by Grigoriev and Krymskaya (1998) on leech treatment of 40 patients with sensorineural disorders of hearing and balance (cochleovestibular) of predominantly peripheral origin: after treatment, as stated, all patients noted a lightness in the head and the noise indicators decreased; no comparison group is named in the retelling, and it is not clear from the text whether these patients had chronic sensorineural hearing loss specifically[B1].
- On sudden hearing loss, Flecken and Michalsen write that hirudotherapy can be considered for it, but they stress that no scientific study data on this subject had been published up to that time[B3].
- Both books list hemophilia and concurrent use of anticoagulants (medicines that reduce blood clotting) among the contraindications[B1][B3].
Treatment specifics
How many leeches, where they are placed, how long a session lasts, and whether to repeat are clinical decisions made by a qualified provider under institutional protocol — not something to self-administer. Discuss the specifics with a clinician experienced in medicinal leech therapy. (Clinicians: where the society's reference books describe a protocol, it is shown in the clinician view — switch the audience selector in the top bar to “Clinician”.)
Key Trials
- Zabolotnyi DI et al. (2019), n=129 · Probl Radiac Med Radiobiol · PMID 31841493 · ASH analysis →
- Morozova SV, Aksenova OV (2009) · Vestn Otorinolaringol [ru] · PMID 19738593 · ASH analysis →
- Senchukova SR, Nikulina GM (2013), n=73 · Fundamental'nye Issledovaniya · Senchukova SR, Nikulina GM. Hirudotherapy in the complex treatment of tinnitus in patients with sensorineural hearing loss of vascular origin. Fundamental'nye Issledovaniya 2013 (not indexed in PubMed) [ru] · fundamental-research.ru
- Zhuravsky SG (dissertation, 2000) (2000), n=104 · Zhuravsky SG. Hirudotherapy in patients of audiological profile. Candidate dissertation abstract, St Petersburg, 2000, as summarized in Baskova IP, Isakhanyan GS. Hirudotherapy: Science and Practice. Moscow, 2004; section 16.13 [ru]
- Zabolotnyi DI et al. 2019129
- Senchukova SR, Nikulina GM 201373
- Zhuravsky SG (dissertation, 2000) 2000104
- Cohort: 3 (75%)
- Case Series: 1 (25%)
Contraindications
- Hemophilia or another bleeding disorder
- Taking anticoagulants (blood thinners such as warfarin or heparin)
- Anemia or suppressed blood formation
- Low blood pressure, shock, collapse or fainting
- Severe wasting (cachexia)
- Intolerance of leeches or a history of severe allergic reactions
- Pregnancy
- Stomach or duodenal ulcer, erosive gastritis
- Acute infectious disease or high fever
- Severe unstable illness, markedly weakened immunity (for example during chemotherapy) or HIV infection
- Drinking alcohol at the time of treatment
- No consent from the patient
- Sudden hearing loss, until it has been evaluated urgently by an ENT clinician and decisions on standard treatment have been made (leeches must never delay this)
- Hearing loss that has not yet been evaluated by a clinician with a hearing test (audiogram)
- Hearing loss in one ear only, or clearly worse in one ear, that has not yet been evaluated with audiometry and MRI or auditory brainstem testing for a lesion of the hearing nerve
- Hearing loss with vertigo, facial weakness, ear pain with blisters, ear discharge, repeated sudden episodes, loss in both ears at once or other neurologic findings, until evaluated
- Active infection or inflammation of the ear canal or middle ear, a draining ear, or a known eardrum perforation
- Severe hearing loss in the only hearing ear
- Cochlear or other implanted hearing device, or recent ear surgery
Related Conditions
Subjective Tinnitus
Investigational for tinnitus; small non-randomized studies, mostly Russian, report less ear noise, and no study using the Tinnitus Handicap Inventory was identified.
Chronic Refractory Tinnitus (Investigational Adjunct)
Investigational adjunct for chronic refractory subjective tinnitus; cognitive behavioral therapy, sound therapy, and hearing aids for concurrent hearing loss remain evidence-based.
Ménière's Disease (Adjunctive)
Investigational adjunct for Ménière's disease with no clinical study identified; standard management (diet, betahistine, intratympanic therapy) remains primary.
Ramsay Hunt Syndrome (Investigational Adjunct, Convalescent Phase)
Investigational adjunct for convalescent-phase Ramsay Hunt syndrome residual facial weakness; antiviral plus corticosteroid started within 72 hours of onset remains evidence-based.
References
- [B1]
Баскова И.П., Исаханян Г.С. Гирудотерапия. Наука и практика [Hirudotherapy: Science and Practice]
Monograph in Russian, 506 pp., ISBN 5-89527-058-1. Chapter 15: sensation at the bite, length of the session; secretion kininases and pain.
- [B3]
Michalsen A., Roth M., Dobos G. Medicinal Leech Therapy
ISBN 978-3-13-143581-1 / 978-1-58890-563-5. Chapter 9, p. 107: perceptions of the bite — a local dragging pain lasting around one to five minutes.
The information on this page is based on the hirudotherapy books listed under References and reflects the experience their authors describe. Sensations and results differ from person to person. This information is not medical advice, a diagnosis or a prescription, and it does not replace an examination by a physician. Do not stop or change any prescribed treatment without your physician. Hirudotherapy has contraindications.