1. Sinus or Ear Barotraumas:

Sinus Squeeze occurs when the air inside your sinus cavity cannot equalize itself with the outside pressure sue to a build-up of mucous or congestion. The pressure build-up in your sinus is often the cause for headaches during ascent or descent. These headaches are identifiable by pain that is usually over the forehead or cheekbones, behind the eyes or on top of the head. Use of a nasal decongestant spray or decongestant pills may help clear your sinuses before a dive.

2. Sinus and Ear Infections:

An outer ear infection, sometimes called “swimmer’s ear,” because it often occurs after prolonged water exposure can cause headaches for divers. This needs to be treated by an ENT by antibiotic eardrops and cleaning of the water in the ear. Outer ear infections are painful and often take longer to heal. Inner ear infections are caused when contaminated water enters the inner ear and causes infection, which can cause pain when pressure changes while diving. Symptoms include earache, decreased hearing and sometimes headaches.

3. Mask Squeeze:

Mask squeeze occurs when the intense pressure underwater pushes the mask tightly against the divers’ face. Usually the diver should compensate the increase in pressure by puffing air into the mask from the nose, however if not carried out, the pressure of the mask against the cheek/sinuses causes small blood vessels around the eye to burst. Often after surfacing the diver may experience a headache as well as hemorrhaging in the eyes. To avoid Mask Squeeze headaches, one must ensure that they have a properly fitting mask, not have the straps on too tight, and constantly equalize the pressure of the inside of the mask on descent.

4. Gas Toxicity:

Often divers in their effort to artificially reduce their air consumption skip breathing, which leads to a build-up of CO2 in the body leading to Carbon Dioxide Toxicity. Symptoms include dizziness, nausea, and headaches. By improper breathing, physical exertion or skipping breaths to increase air time, your lungs are unable to expel the carbon dioxide build-up causing the symptoms.
Gas Toxicity caused by impure air in your tank can cause carbon monoxide gas toxicity which can also lead to headaches.
For Gas Toxicity administer pure oxygen to the affected diver and allow the diver to rest. If the symptoms are severe, then rush the diver to the hospital to be treated.

5. Diesel Fumes:

Similar to Gas Toxicity, but caused on the surface due to the dive boat diesel emissions, inhalation of Carbon Monoxide or smoke fumes can also result in headaches. Make sure you are seated upwind from the engine exhaust on the dive boat to prevent this.

6. Dental Problems:

Tooth pain during diving caused by tiny pockets of air within your dental work creating a pressure vacuum as you ascend and descend may manifest itself in the form of a headache. A bad-fitting mouthpiece can also cause headache by causing discomfort in your teeth and jaw.

7. Decompression Illness:

Headaches are also a symptom of Decompression illness, and often manifest themselves when bubbles are formed in or near the blood vessels surrounding the brain and spinal cord. If you’ve had an irregular dive profile, or missed safety/decompression stop, and experience headaches, along with the other symptoms such as pain in joints and / or muscles of the arms, dizziness, fatigue or itchy skin, get yourself checked and treated immediately for DCS or Decompression Illness.

8. Dehydration headache:

A dehydration headaches feels like a throbbing pain, especially when you stand-up. The sensation of a head rush which becomes a dull throbbing headache is often due to insufficient fluid intake, or excessive alcohol or caffeine consumption before the dive which act as diuretics. The solution is to constantly stay hydrated on your dive, drinking plenty of water and fluids before and after your dive.

9. Neck/Upper Back Sprain:

Often the incorrect positioning of the Scuba air tank on the upper back may cause neck sprains which can lead to headaches. Also constant craning your neck to look at things rather than turning your full body may also result in neck/upper back injuries leading to headaches.