What condition can occur if a diver experiences a blockage in ear pressure regulation?

When a diver experiences a blockage in ear pressure regulation, it can lead to middle ear barotrauma. This condition occurs due to the inability to equalize pressure between the outer ear and the middle ear, most commonly when a diver ascends or descends in the water. If the pressure inside the middle ear is not equalized with the pressure in the surrounding water, it results in negative pressure in the middle ear, potentially causing pain, fluid accumulation, or even damage to the eardrum and other structures within the ear.

Factors that contribute to this blockage may include nasal congestion, allergies, or improper equalization techniques. It's critical for divers to be aware of how to properly equalize their ears to prevent this painful condition and continue their dive safely.