STARFISH: A research study to find out whether steroids given by mouth, an injection through the ear drum, or a combination of both treatments is best at improving hearing after unexplained sudden hearing loss.

Inclusion criteria:
Current inclusion criteria as of 13/11/2025:
1. Adults aged 18 years or over
2. Diagnosis of new-onset ISSNHL: a new increase in sensorineural thresholds of 30 decibels (dBHL) or greater affecting each of three contiguous pure-tone frequencies (out of 0.5, 1.0, 2.0, 4.0 kilohertz (kHz)) confirmed with a pure tone audiogram, having an onset over a period of 3 days or less according to the patient's history*
3. Onset of hearing loss within 4 weeks prior to randomisation
4. English spoken as a first or second language

*Where audiometry is not available prior to the ISSNHL and there is a history is of equal hearing in both ears prior to the sudden loss, hearing loss will be defined in relation to the opposite ear’s thresholds. Where audiometry is not available prior to the ISSNHL and there is a history of different hearing in both ears prior to the sudden loss, then the candidate can only be included if the ISSNHL occurred in the better hearing ear and the measured thresholds are at least 30dB below the contralateral ear at three contiguous pure-tone frequencies (out of 0.5, 1.0, 2.0, 4.0 kilohertz (kHz)) confirmed with a pure tone audiogram.

Previous inclusion criteria:
1. Adults aged 18 years or over
2. Diagnosis of new-onset ISSNHL- sensorineural hearing loss of 30 decibels (dBHL) or greater occurring within a 3-day period and including 3 contiguous pure-tone frequencies (out of 0.5, 1.0, 2.0, 4.0 kilohertz (kHz)) confirmed with a pure tone audiogram occurring within a 3-day period (based on participant-reported history)
3. Onset of hearing loss within 4 weeks prior to randomisation
4. English spoken as a first or second language

Exclusion criteria:
1. Identified cause for hearing loss (not idiopathic)
2. Bilateral ISSNHL
3. Received prior steroid treatment for the same episode of ISSNHL
4. Medical contraindication to high dose systemic steroids
5. Previous history of psychosis
6. On oral steroid therapy for another condition
7. Known adrenocortical insufficiency other than exogenous corticosteroid therapy
8. Hypersensitivity to the active substance or to any of the excipients
9. Has a systemic infection unless specific anti-infective therapy is employed
10. Has ocular herpes simplex
11. Has ipsilateral acute or chronic active middle ear disease (including acute otitis media, chronic suppurative otitis media and cholesteatoma, excluding dry perforation)
12. Does not have the capacity to provide written informed consent