It is Tuesday. The dive was Saturday. One ear still sounds like it is underwater when you chew, and voices on that side arrive through a pillow.
Three separate problems produce that feeling, and they are treated differently: water sitting in the outer canal, fluid behind the eardrum after a squeeze on descent, and a reverse block on the way up. DAN's ear reference sets the point for getting examined in hours rather than days. Discharge of fluid or blood from the ear canal, or ear pain and fullness lasting more than a few hours, is a reason to see a doctor. By Tuesday, the question of whether to bother somebody has been answered for you.
Is it water in the ear canal or fluid behind the eardrum?
The two feel similar and come from opposite sides of the eardrum. Water trapped in the outer canal moves. Tilt your head and the sound shifts, hearing goes muffled and then clears, and the sensation is closer to blocked than sore. It gets out the way it came in.
Fluid behind the drum is the other thing entirely. It arrives when the middle ear cannot be equalised properly on descent, and the pressure difference pulls fluid, and sometimes blood, into a space that should contain air. DAN describes the early version as clogged or stuffed ears that can progress to severe pain, with fluid and bleeding following a deeper descent. That fluid has no route into the canal. It drains through the Eustachian tube, and the tube refusing to open is the reason it is there in the first place.
Which one you have is a doctor's call, because it is settled by looking at the eardrum. DAN's guidance while you wait is short: with fullness in the ears after diving, stop diving. The descent side of this, and the techniques that prevent it, sit in the article on equalising your ears.
What is a reverse block and why does it happen on the way up?
Descent and ascent ask opposite things of the middle ear. Going down, air has to be added to the space behind the drum. Coming up, the air already in there expands and has to escape. If the Eustachian tube will not open on the way up, expanding air is trapped with nowhere to go, and it presses outward instead. Pressure, fullness, pain and sometimes vertigo, all of it starting during the ascent rather than at depth.
DAN Europe names three usual causes: poor equalising on descent, diving with a cold, and diving on decongestant drugs that wear off at depth. The last one is worth understanding even though no dive shop can advise on medication. The drug opens the tube at the surface, the dive outlasts the drug, and the ascent finds a tube that has closed again. Whether to take anything at all is a decision for a doctor who knows your history, not a counter conversation. The congestion side of it is covered in diving with a cold or blocked sinuses.
One move to leave alone afterwards: forcing a blocked ear repeatedly once you are back on land. DAN's advice for a suspected inner-ear injury runs the other way, avoiding equalisation attempts, heavy exertion and altitude until somebody has looked at the ear. Pushing air at a tube that will not open adds pressure to a space that already has too much.
Can diving cause an ear infection?
Repeated immersion sets it up. DAN Europe's explanation is mechanical rather than mysterious: water swells the cells lining the ear canal, and bacteria that live harmlessly on the surface of that skin get underneath it. The result is otitis externa, swimmer's ear, which DAN defines as acute inflammation or infection of the external auditory canal producing ear pain and pus discharge.
It builds over days, which is why it catches course students and anyone diving a full weekend rather than a single dive. Itching first, then tenderness, then swelling. DAN notes that untreated cases can make jaw movement uncomfortable, which is the chewing that sent you looking for this article. Discharge from the canal puts you past the threshold above.
Prevention is drying, not dosing. Keep the ears dry between dives and out of the water afterwards, and put nothing into the canal to speed it along. Cotton buds and improvised drops damage the same skin that is already compromised. Return to diving comes when a physician decides the infection has resolved, and that sequence is not negotiable, because water on an infected canal restarts the process.
When should you see a doctor about an ear after diving?
DAN's criteria are usefully specific, and a few of them are urgent rather than routine.
- Discharge of fluid or blood from the ear canal. Evaluation, without waiting to see whether it settles.
- Pain and fullness lasting more than a few hours. This is the everyday threshold and the one most divers sit well past before phoning anybody.
- Vertigo, the room spinning, or nausea with it. Urgent. On a dive it is dangerous in its own right, and afterwards it points at the inner ear rather than the middle.
- Hearing loss or ringing. DAN notes that inner-ear barotrauma often takes the higher frequencies, and that divers may only notice hours later.
- Any of the above with a flight booked. A cabin pressure change over a tube that will not open reproduces the problem in the air, where nobody can look at it.
The vertigo and hearing group carries a complication worth knowing. Inner-ear barotrauma and inner-ear decompression sickness produce similar symptoms and receive opposite treatment: hyperbaric oxygen treats the decompression case and is contraindicated when barotrauma is the likely cause. The difference is often in the timing, an equalising failure early in the dive against symptoms arriving at the end of it. Sorting that out is a doctor's work, and it goes faster with an honest account of the dive profile and when the ear first complained. DAN Europe's recommendation is a physician, preferably an ENT specialist.
Can you dive the next day with a blocked ear?
No, and the reason is practical rather than precautionary. An ear that will not clear on the surface will not clear at four metres, and a tube already inflamed by one failed equalisation gets worse with a second attempt. DAN's instruction for post-dive fullness is to abstain from further diving. A student who arrives on day two with a blocked ear should expect to sit the dive out and reschedule it.
Nobody can tell you how long yours will take to clear, and figures quoted on forums are somebody else's ear. The useful measurement is the threshold, not the countdown: past a few hours of pain and fullness, or any discharge, somebody qualified needs to look. Consecutive days of course diving are exactly the pattern DAN flags for congestion that accumulates, so the ear that felt slow on Saturday is the one to mention on Sunday morning rather than after the dive.
Sources
- DAN, Ears and Diving: ear injuries. Middle-ear barotrauma, the evaluation criteria, reverse squeeze, swimmer's ear, and the inner-ear barotrauma against decompression sickness distinction.
- DAN, Ears and Diving reference book. The anatomy of the middle ear and Eustachian tube behind all three problems.
- DAN Europe: ears and diving. Reverse block causes including decongestants wearing off at depth, how immersion produces outer-ear infection, and the recommendation to see an ENT specialist.
Frequently Asked Questions
How long should a blocked ear last after diving?
No responsible figure exists, because the cause decides it. DAN's threshold for evaluation is ear pain and fullness lasting more than a few hours, or any discharge of fluid or blood from the canal.
Is it trapped water or fluid behind the eardrum?
Trapped water shifts when you move your head and drains out of the canal. Middle-ear fluid does not move with position and clears through the Eustachian tube. Telling them apart means looking at the eardrum.
What is a reverse block?
Air in the middle ear expands during ascent. If the Eustachian tube will not open, that expanding air is trapped and presses outward, producing fullness, pain and sometimes vertigo on the way up rather than at depth.
Should you keep equalising to clear a blocked ear?
No. DAN's guidance for a suspected inner-ear injury is to avoid equalisation attempts, exertion and altitude until the ear has been examined. Forcing air at a tube that will not open makes the situation worse.
Can diving give you an ear infection?
Repeated immersion swells the skin lining the ear canal and lets ordinary skin bacteria underneath it. That is otitis externa, or swimmer's ear. Return to diving waits until a physician decides the infection has cleared.
Can you dive the next day with a blocked ear?
DAN's instruction is to abstain from further diving while fullness is present. An ear that will not equalise on the surface will not equalise on descent, and a second attempt inflames a tube that is already struggling.
This is general information, not a substitute for a dive medical or advice from a doctor trained in dive medicine. In an emergency, contact your local emergency services and DAN Southern Africa on +27 82 810 6010.
Reviewed September 2026. Devon Ford runs Scuba Evolution, a PADI 5 Star Dive Centre in Glenvista, Johannesburg.
