Medical FAQs

Here's a list compiled over the years of commonly asked questions. The list was created by DAN MDs and represent specific, evidence-based recommendations our member should take into consideration.


I’m a SCUBA and apnea instructor. One of my students suffers from an arthritic disorder called psoriatic arthritis and he is being treated with Metotrexate 15mg. I would like to know whether his case represents a contraindication for recreational diving.
The Psoriatic Arthritis is a musculo-skeletal inflammatory chronical disease and it is itself a contraindication for diving as it makes the body vulnerable to decompression stress.

Moreover, the Metotrexate intake could put your student at a further risk for its side effects which includes lung tocixity  and myelotoxicity. Hence you need to have your student’s fit to dive necessarily verified by a specialist in diving and hyperbaric medicine.

I have been diagnosed with a 2nd Grade Patent Foramen Ovale (PFO). I know I can undergo surgery and have it closed with an umbrella device. Would the surgery be a resolution? Can I dive regularly after it?
In accordance with the Swiss Underwater and Hyperbaric Medical Society (SUHMS) guidelines, a diver with 2nd and 3rd Grade PFO can dive according to “low bubble diving recommendations”:
  1. Perform the deep phase of the dive first and avoid yo-yo dives (avoid repetitive entry into the 0-10 meter zone)
  2. Reduce surfacing speed to 5 meters per minute in the upper 10 meters
  3. Perform a safety stop at 3-5 meters depth for at least 5-10 minutes
  4. Don’t go to the limit of a no-decompression dive - Don’t perform dives with a decompression stop obligation
  5. Surface interval of at least 4 hours before the next dive
  6. Maximum of two dives a day
  7. Avoid intense skin warming after the dive (e.g.: sunbathing, hot shower, sauna)
  8. Diving with a Nitrox, using air decompression tables or computer setting, pay attention to oxygen toxicity
  9. Special underwater computers or software may reduce the risk


Moreover, to decrease the risk of bubbles transfer into the arterial blood stream: 

  • Avoid strenuous physical efforts during the last 10 metres of surfacing (fining or swimming against current at the end of the dive)
  • Avoid exhausting physical activity during two hours following the dive
  • It is absolutely prohibited to dive when having a cold. Coughing and forced Valsalva maneuver facilitate bubble transfer into the arterial blood stream.


Nonetheless, the surgery will be effective and after a complete healing you can go back to diving again. 

I’m 56 and in good health. Three years ago I had an idiopathic pulmonary embolism. I am no longer taking anticoagulant medication, and I remain very active. Can I dive?
Several things need to be considered when evaluating fitness for diving after a pulmonary embolism. First is the cause, because it is important to determine the risk of recurrence. Determining this risk may be difficult in your case because your embolism was idiopathic (of unknown origin).

Next the damage to the lung must be assessed.
Scarring and/or adhesions may prevent proper gas exchange, making diving unsafe. DAN is not in a position to determine an individual’s fitness for diving; a physician must make that decision. The best way to begin the process of assessing your fitness to dive is to get a high-resolution spiral CT scan to determine if there is damage to the lung tissue. If there isn’t, and exercise tolerance is normal, diving can be considered.
Pulmonary hypertension and other associated medical conditions may restrict your exercise tolerance.
Certain medications can have side effects that might limit your ability to dive safely, so you should discuss all medications you take and your complete medical history with your doctor.
If your doctor approves your return to diving, request this approval in writing so you can provide documentation to dive operators, who will likely require a written statement before allowing you to dive.

I made two dives about a month ago. The first was to 27 meters for 20 minutes, and the second was to 11 meters for 35 minutes. I was well within my computer guidelines, we did not do a safety stop, and I may have had one slightly fast ascent. I was OK until about four days after the dive, when I noticed a sharp pain in my elbow. If I'm not using my arm, I don' t notice any pain at all. But if I rotate my forearm or bend my elbow, I still get a dull ache. Is there any way this could be related to my dives?
If you were symptom-free for four full days, then it is unlikely that subsequent symptoms are related to decompression illness and your dive. The nitrogen you absorbed during your dives has to follow the physiology of basic gas laws - it cannot stay in the body tissues once the partial pressure of nitrogen in the ambient air we breathe drops down to sea-level pressures.

Although nitrogen leaves the body in a much slower fashion than we take it on, it still must leave. After diving, you should be equilibrated to ambient nitrogen in 24 hours.
If the pain can be produced with movement of the affected joint only, then it is more than likely a musculoskeletal strain or injury.

The pain generally associated with decompression illness is not affected by movement or lack of movement and usually remains fairly constant.
The ability to reproduce the symptom with movement indicates a stress or repetitive movement injury.
If you have not seen your personal physician it would be wise to do so.
Appropriate therapy is indicated to prevent permanent injuries.

I have an allergy to latex. Is "any" part of the diver's equipment made with latex? I am interested in taking up the sport, but if there is any latex involved, I can't.
The overwhelming majority of diving equipment uses either silicone or neoprene rubber. Latex is most often used in what are known as dry suits. These exposure suits have water-tight seals at the neck and wrists.

 This where you would find the majority of latex, but this is not an entry-level issue. There are pieces of accessory equipment that are made of latex, but there are many alternatives that are made of other materials. You have a great deal of control with latex exposure with your own equipment. However, when you are diving from a resort, especially a dive boat, incidental encounters with latex are certainly possible. The severity of your allergic reactions needs to be considered as the best indicator of whether diving would be an appropriate pursuit. Please feel free to contact our medical division if you have any further questions. Also your local dive shops are a good resource for discussing specific equipment issues.

Last week I got a saltwater aquarium with an anemone and a small lionfish. I saw the lionfish swimming through the anemone and thought it was going to hurt the anemone, so I reached in the tank and pushed the lionfish away. It nailed me on the fingers, and now they're all swollen and blistered. Is there anything I can do?
Lionfish (as well as scorpionfish and stonefish) possess dorsal, anal, and pelvic spines that transport venom from their venom glands into puncture wounds. Common reactions include redness or blanching, swelling and blistering (lionfish). The injuries can be extraordinarily painful and occasionally life-threatening (in the case of a stonefish).

The Treatment

Soaking the wound in non-scalding hot water to tolerance (43.3 to 45˚ C) may provide dramatic relief of pain from a lionfish sting; is less likely to be effective for a scorpionfish sting, and may have little or no effect on the pain from a stonefish sting, but it should be done nonetheless, because the heat may inactivate some of the harmful components of the venom.
If the injured person appears intoxicated or is weak, vomiting, short of breath or unconscious, seek immediate advanced medical care.
Wound care is standard, so – for the blistering wound – appropriate therapy would be a topical antiseptic (such as silver sulfadiazene cream or bacitracin ointment) and daily dressing changes. A scorpionfish sting frequently requires weeks or months to heal, and therefore requires the attention of a physician. There is an antivenin available to physicians to help manage the sting of the dreaded stonefish.

Is it safe to dive with a perforated tympanic membrane?
A perforated tympanic membrane (ear drum) can be caused by diving, or have other non-related causes. Most traumatic perforations heal spontaneously.

Following an appropriate time after they have healed, you can return to diving if your physician feels the healing is solid and there is no evidence of Eustachian tube problems.
This usually takes about two months after it is healed.
If the perforation does not heal, then an ear surgeon can repair the damage.
After healing has taken place, the same rules as above apply. It is important to check for chronic nose and sinus problems if there is no healing.

Chronic perforations that do not heal are a contraindication to diving. Some have advocated the use of ear plugs for these individuals, but if there is any water leakage, it could cause a severe infection.

This is NOT an emergency. I have a question: I’m a musician (saxophone, flute, and clarinet) and would like to know how long I should wait with playing an instrument after diving without increasing the risk of a decompression accident. After a dive it is not advisable to do any physical exertion. I always wait until my dive computer Galileo Sol doesn’t show any desaturation time anymore. Are there any guidelines?
Being this the case of wind instruments, the risk relates to the possible increase in intra-thoracic pressure that can facilitate the arterialisation of potential circulating venous bubbles, both having a cardiac or pulmonary right to left shunt, but also with ideal anatomical conditions.

This is because of significant quantities of VGE (venous gas emboli) which increase the right ventricular pressure and force the filter of the lung.

Waiting for the total desaturation time, shown on the Galileo diving computer, is not wrong but very precautionary.
The problem lies on VGE presence which cannot be detected after 3 hours from surfacing, in case of recreational dives. Time should be extended with advanced/tech dives but also in this case, VGE are rarely observed after 4-6 hours.

Can people with cochlear implants scuba dive?
Diving is a sport with some inherent risk and people with deafness or ear surgery may be at increased risk with scuba diving.

Regarding return to diving after implantation, a recipient should wait a minimum of 3 months after implantation, be able to autoinflate (equalize) the operated ear, be completely healed, free of symptoms such as vertigo, imbalance and pain and have complete resolution of the post-operative hemotympanum (blood behind the ear drum).
On examination with a microscope, the fistula test should be negative and the TM should not contact the electrode on maximum medial excursion.
(Your doctor will gently puff air into your ear canal to see if it makes you dizzy or if the eardrum touches the CI electrode).

Your neurological examination should be normal. Make sure to discuss these recommendations with your otologist and be sure to follow his/her recommendations.

I have a question about the degassing of my body. I am a technical diver and I'm always pretty tired after deep dives. I've played around with my gradient factors, but the problem persists. I have my whole body tattooed, with exception of head and feet. My question is: does degassing takes longer because of the ink in my body, or is that a myth?
This has no effect on the rate of degassing. The desaturation rate differs for everybody, even depending from day to day.

So the only logical approach is to reduce the saturation – This can be calculated using the depth, dive time and Nitrogen concentration (inert gas) in the breathing mix.

I have a student who wants to learn to dive, but has cerebral palsy. What are the issues?
This condition describes brain injury present at birth and which is manifested by some degree of weakness. This includes a wide variety of clinical problems, ranging from ‘walks abnormally’ to very severe and disabling handicaps.

Some cases present accompanying seizures, learning disability and speech defects.
Diving fitness depends entirely on the extent of disability in the individual case.

Candidates with mild problems may qualify; candidates with more severe disabilities may qualify through one of the scuba programmes for disabled people.
The absence of seizures and the ability to master water skills are particularly important.
For participation in scuba, case-by-case selection is needed.

When my son was young, he went through a period where he fainted several times. The doctors never really knew why and he seemed to grow out of it. Now he wants to learn to dive. Will his history of fainting present a problem?
This is a difficult question to answer since many variables can cause transient alteration of consciousness. These alterations of consciousness include fainting, a drop in blood pressure which is very common in young people, an alteration in heart rhythm that is more common in older people, the effects of medication and psychological events, such as hallucinations.

As with epilepsy, any loss of consciousness underwater is likely to have a bad outcome. When diving using nitrox or mixed gas as a breathing gas, increased partial pressures of oxygen can increase the likelihood of seizures. Increased carbon dioxide may also increase seizure risk. The best advice is to get a precise diagnosis of the cause of these altered states of consciousness: effective treatment is often available. You cannot make a reasonable fitness-to-dive decision until this is sorted out. It may take some time and a visit to a neurologist or other specialist is necessary.

In the absence of a recompression chamber, does DAN recommend treating a "bent" diver with in-water recompression?
DAN does not recommend that symptomatic divers be recompressed while breathing standard air in the water. In some areas of the world, divers are treated with in-water recompression because of a lack of chamber facilities. At one time, divers were treated in recompression chambers using the U.S. Navy treatment tables and breathing air instead of oxygen.

The failure rate was high. It is unlikely that in-water recompression using air is more effective than those old treatment tables. In-water recompression with the diver breathing oxygen instead of standard air has been used successfully in some areas.
However, in-water recompression has its own dangers and should not be attempted without the necessary training and equipment, or in the absence of someone who can assess the diver medically.
The resources required for in-water recompression usually exceed the ability of those at the scene to properly assist the injured diver.

In-water recompression of any type is not currently recommended by DAN.

Our 12-year-old daughter has shown a great deal of interest in learning to dive and as a family, we have just experienced an introductory dive at our local dive shop. At our daughter’s recent physical exam, her pediatrician expressed some concern for her bone growth and scuba diving. It seems there are many youngsters involved in diving. Should we be concerned for our daughter’s growth and development if we decide to allow her to dive?
In general, the concern is focused on the possible formation of micro-bubbles in the bloodstream of all scuba divers. We often call these ‘silent bubbles’, which fail to produce any detectable symptoms, but are known to be present in the bloodstream of many divers.

No one knows to what extent these bubbles could form in younger divers.
Theoretically, these bubbles may obstruct blood flow in nutrient vessels to the epiphyseal plates, also called growth plates.
This process may cause focal areas of avascular necrosis or angular deformity to the developing weight bearing long bones, particularly the femoral head, distal femur, and proximal tibia. Young divers should stay within the guidelines of the junior divers program.
This will limit their exposure to nitrogen, by restricting depth, time and number of dives as well as allowing for maximum surface intervals to promote nitrogen off gassing.
Although the concern is theoretical, conservative dive practices are recommended for junior divers.

I was diving over the weekend, doing three dives each day, finishing about noon on Sunday. I had some trouble clearing on both days, and on the last dive I had a reverse block. I can hear just fine and I don't have any pain, but on the side of my neck I have several little bubbles that I can press on but which are not painful. Have you ever heard of this?
Air bubbles don't normally exist under the skin in the neck, or anywhere else in the body. Although it may seem as though this trapped air must have come from the middle ear, this would be a bit unusual, since you have no ear pain or other symptoms, such as a ringing or roaring sound, or even loss of hearing.

Middle ear barotrauma can easily damage the tympanic membrane or one of the more delicate internal membranes associated with sound transmission inside of the ear.
Although no one can say for sure, it is more likely that this trapped air - or subcutaneous emphysema - originated from pulmonary barotrauma.

Sometimes the lungs are over-pressurized, for instance, when we have difficulty clearing. This can happen when we attempt to put air into the sinuses and middle ear with more force than is necessary.
This can actually increase the amount of pressure in the air spaces of the lung, which then allows air to escape through lung tissue, where it can travel up to the shoulder, neck or even the face. Subcutaneous emphysema does not require recompression treatment.

However, it is a good idea to be evaluated by your physician to determine the underlying cause of the air bubbles.

Is it possible to dive after having suffered a stroke?
Stroke, or loss of blood supply to the brain, causes damage to part of the brain, or bleeding from a blood vessel in the brain, which results in similar injury. Strokes vary in severity and the resulting disability depends on the size and location of the event.
  1. Most strokes occur in older people. The stroke itself identifies the person as one who has advanced arterial disease, thus a higher expectation of further stroke or heart attack.
  2. The extent of disability caused by the stroke (e.g., paralysis, vision loss) may determine fitness to dive.
  3. Vigorous exercise, lifting heavy weights and using the Valsalva method for ear-clearing when diving all increase arterial pressure in the head and may increase the likelihood of a recurrent hemorrhage.
  4. While diving in itself entails exposure to elevated partial pressures and elevated hydrostatic pressure, it does not cause stroke.
  5. There is certainly increased risk in diving for someone who has experienced a stroke. Exceptional circumstances may exist, such as cerebral hemorrhage in a young person in whom the faulty artery has been repaired with little persisting damage.
    This type of recovery may permit a return to diving, with small risk. Each instance, however, requires a case-by-case decision, made with the advice of the treating physician, family and diving partners. Consulting a neurologist familiar with diving medicine is also advisable.
  6. There is a similar concern for significant residual symptoms, as with post brain tumor surgery.

I’m a 76-year-old diver and, while undertaking an Exercise ECG, the doctors detected an Atrial Fibrillation. After urine and blood tests, the haematologist prescribed me Xarelto (Rivaroxaban). Can I still dive?
Atrial Fibrillation, not previously detected, was diagnosed through the Exercise ECG and this is why you are now under treatment with Xarelto (Rivaroxaban).

If this condition, although chronical, is characterized by a normal cardiac frequency with no symptoms during the physical exercise, as in your case, then safe diving is still possible.

I was diagnosed with an ailment called Arteritis Temporalis 10 months ago and was treated with a high dose of Prednisone (or cortisone) (60mg/day). The dosage of prednisone is being diminished each month. Now it is down to 15 mg/day and I am feeling OK. Is this a contraindication for recreational diving? Should I restrict my dives to 20-meter maximum?
For what concerns recreational scuba diving, not much is known about the interaction of cortisone, giant-cell arteritis (also known as temporal arteritis) and diving. In such cases it is wise to be prudent.

I do not think major problems are to be expected, but believe that limiting the depth and dive times are wise decisions.

I have two medical questions, both related to dental problems: how long should I wait to dive after a tooth extraction? And how long is it recommended not to dive after a bone transplant to place a future screw?
A tooth extraction does not necessarily require to interrupt your diving activity. If you did not have complications, you can dive whenever you want and feel fine. If you have received a bone transplant prior to implantation of dental prostheses, it is advisable to apply a prudent resting period.

Diving does not mean any particular problem for both procedures. Therefore, as soon as your maxillofacial surgeon authorizes you to perform normal activities of daily life, you will also be able to dive again.

Last week I caught a cold and high fever, with respiratory difficulties. My doctor, after a medical examination, diagnosed a bronchospasm and gave me the following medications: 3 days with Azithromycin antibiotic and then Ambroxole. It seems now that I recovered my nasal respiration and I will be clinically checked in the next few days. I would like to have your opinion before diving again.
You can go back to diving safely again only after your doctor confirms that the acute inflammation

at upper airways and bronchial level is completely recovered and thus you may discontinue the medication therapy.

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