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 have to teach an OWD course to a student who has silicone breast implants. I would like to know if there are any contraindications to diving due to depth (pressure) and to nitrogen being absorbed by the silicone.
There is not a lot of information on the durability of silicone implants when diving. What is known basically refers to breast implants, and generally states that they are safe and reliable. The specific precautions to be taken are generic and mechanical.

The - actual and common - possibility that inert gas bubbles could form inside the implants, does not appear of considerable importance, since this phenomenon would remain limited to the inside of the implant, and therefore without causing any damage.
This applies both to implants made only of silicone, and to saline implants.

There is no information of statistic or scientific interest regarding soft tissue fillers, or injectable implants, even if theoretically, there could be the risk of a localized production of bubbles at a different rate from surrounding tissues.

However, considering that the filler is injected into the tissue and is free to move in the surrounding areas, it is possible that a gas exchange will take place, but with a non significant risk of damage.

I've recently been asked to teach a course to a 16-year-old autistic girl. I would like to know if it's possible and if there are any potential consequences or contraindications.
Autism, for countless reasons, presents many contraindications to diving. Among others, a communication deficit that could pose the girl in great danger in the underwater environment.

Since the evaluation is extremely delicate and complex, I advise you to talk to a specialist in diving medicine, who should visit the girl and can then give you a direct assessment.
His/her opinion will then need to be compared and cross-checked with that of the neuropsichiatrist who follows the girl.

I am a beginner diver and I have difficulty equalising my ears. I have heard that I should not dive if I use nasal decongestants, but is it safe to dive if I use nasal steroids?
It is very common for new divers to experience difficulty to equilise their middle ear spaces. As you gain experience and learn the techniques that work best for you, you will find equilisation easier in general. There is little scientific data regarding any specific medication and diving, but based on the known side-effects of steroids nasal sprays, there is little reason to suspect that they would be problematic for divers.

Even though the fast-acting nature of decongestants can be appealing, there are several reasons why steroids may provide a safer option.
The swelling and inflammation of the cells lining the Eustachian tubes, middle ear space and sinuses may lead to occlusion and barotrauma. The mucous membranes lining these structures are vascularised and decongestants provide a short-term solution to congestion by constricting the blood vessels in the mucous membranes, which decreases swelling.

When the decongestants wear off, however, the blood vessels are no longer constricted. The after effect is that the blood vessels will swell and may become more engorged with blood that before, which is known as the rebound-effect.
Unlike decongestants, steroids do not act as vasoconstrictors, so there is no rebound. Another disadvantage of decongestants is that they are only intended for short-term use and may lose effectiveness with habitual use.
The steroid, fluticasone propionate, and similar medications, on the other hand, are intended to be used over substantially longer periods of time than decongestants. So prevention of a middle-ear barotrauma is best achieved by avoiding nasal decongestants and by training the diver in correct middle-ear equalization techniques during descent.

What are the effects PMS will have on me when I dive?
Premenstrual Syndrome, or PMS, is a group of poorly understood and poorly defined psychophysiological symptoms experienced by many women (25-50 percent of women) at the end of the menstrual cycle, just prior to the menstrual flow. PMS symptoms include mood swings, irritability, decreased mental alertness, tension, fatigue, depression, headaches, bloating, swelling, breast tenderness, joint pain and food cravings. Severe premenstrual syndrome has been found to exacerbate underlying emotional disorders. Although progesterone is used in some cases, no consistent, simple treatments are available.


Research has shown that accidents in general are more common among women during PMS. If women suffer from premenstrual syndrome, it may be wise to dive conservatively during this time. There is no scientific evidence, however, that they are more susceptible to decompression illness or dive injuries/accidents.

Also, individuals with evidence of depression or antisocial tendencies should be evaluated for their fitness to participate in diving: they may pose a risk to themselves or a dive buddy.

I am an active diving instructor and need to have a molar tooth extracted and get an implant in its place. I would like to know how long you recommend waiting before going back to diving, under the supposition that there are no complications with either the extraction or the implant.
At this point, surgeons have not developed uniform recommendations related to oral surgery and scuba diving: generally, the more complicated the surgery, the longer the wait before diving. Surgical complications will add to this time, as can any underlying medical conditions, tobacco use and alcohol consumption.

During post-surgical osseointegration (the fusion of the implant into the bone), it is necessary to avoid anything that could apply pressure to the skin over the implant and cover screw or the healing abutment.

Diving too soon after surgery with its resultant pressure, no matter how slight, could damage the site. For example, if the regulator’s bite tabs are over the implant site, transmitted biting forces can result in implant failure. There are other considerations as well. Diving should be suspended for as long as it takes to avoid other complications associated with oral surgery:

  • revascularization (resumption of blood flow);
  • stabilization of the implant;
  • oral and sinus cavity pressure changes;
  • ability of the patient to hold a regulator in the mouth; and
  • use of medications for pain or infection.


Bone grafting procedures and sinus surgery are more complex and will require a longer waiting period. The larger the graft site, the longer the wait. Some doctors will recommend avoiding any activity that causes micro-movement for at least six months. It can actually take up to one year for complete bone healing at an implant site. While diving sooner than one year may not cause a problem, your surgeon should determine the appropriate time period. Even if your surgeon doesn’t dive, follow his or her advice.

As your implant is a molar, then the problem with the regulator bite does not apply but the other concerns remain.

I'm concerned about diving as I get older. Will the bone loss from osteoporosis make a difference in my diving?
To date, we have not had significant pool of women who: are post menopausal and at risk of osteoporosis (menopause average at 50, osteopenia at 60-65, and fractures starting at 70-75) or have a significant diving experience including appropriate number of dives at profound depth which put them at risk for osteonecrosis

Therefore, we have no data on coincident osteoporosis and osteonecrosis in women at risk (or men for that matter).

The pathophysiologic mechanisms leading to osteoporosis and osteonecrosis are different.

Osteoporosis results from decreases in osteoblast activity and relative increase of osteoclast activity, resulting in bone resorption and demineralization.
The infarction of the microcirculation of bone is the triggering mechanism for osteonecrosis. Women are at increased risk for osteoporosis given that their overall lifetime peak bone mass is lower than men and that the loss of estrogen during menopause, greatly accelerates the rate of bone demineralization.

All we can say at this point is that women should dive as conservatively as possible, thereby trying to minimize their risks of osteonecrosis, so as not to impose this bone damaging disease on top of their already increased risk of fracture due to Type I estrogen dependent osteoporosis.

I have been invited to a diving weekend on El Hierro, Spain. The accommodation where the divers are staying however is at about 1000 mt altitude. There will be 2-3 dives per day, varying depths, all well within limits. What the minimum surface interval should be before ascending to the accommodation?
Be aware that a change of altitude post dive, in excess of approximately 700m is considered carrying the same risk as flying after diving. As your transition will be of 1000m then this applies to you.

The most prudent is to leave 24 hours before flying or going to high altitude, but the minimum guidelines established by DAN and the Undersea and Hyperbaric Medical Society for flying/altitude (Sheffield and Vann 2004) are:

  • A single dive within the no-decompression limits: 12 hours
  • Repetitive dives or multiple days of diving: 18 hours
  • Decompression dives (planned or unplanned): substantially greater than 18 hours


This means that, with 2-3 dives a day you would be required to wait at least 18 hours.
Since this seems impossible to do, you are strongly advised to either restrict your diving to a single dive daily, to permit yourself an adequate surface interval, or change accommodation.

I would like some information regarding the best contraceptive method to use, more compatible with diving. I am oriented towards the copper-based intrauterine device (IUD), which does not involve taking hormones.
At present, there are no medical indications that favor one contraceptive method over another with regard to being exposed to decompression stress. There are no clinical trials or data on the IUD, however I do not see any particular contraindications with regard to its use while diving.

As a rule, if no side effects or a documented greater individual risk of thrombotic events are present (but this would also affect the prescription of the contraceptive), also the use of oral contraceptives does not have any contraindications connected to diving.

This said, the practice of choosing more conservative dive profiles is strongly advised (dives without decompression stops, no more than two dives a day, maximum depth within 30 meters, bottom time within 70-75% of the maximum limit, possible use of Nitrox with dive times calculated for air).

During my last dive, I hit a sea urchin and the spines went in my thigh. I wasn't able to remove all of them so I just let it heal thinking they would just fall off but, until now, the spines are still inside and sometimes my thigh swells up. Can you please let me know what I can do?
If the spines are only small fragments then the body will eventually absorb them.

If they are large then it would be best to go to a doctor to remove them as otherwise they will cause a foreign body granuloma which, although not a problem of health concern, may leave a noticeable ‘bump’ in the skin.

Four days ago I came into contact with a jellyfish in the Mediterranean Sea. At the pharmacy I was advised to use Flubason 0.25%, desoximetasone skin cream, but it doens't seem to do much in terms of relieving irritation and itchiness. Is there something I can do to help the healing process?
The normal therapy, in such cases, is always and mainly based on the use of local cortisone-based ointments or creams, and in addition, on the use of antibiotic preparations if there's the risk of an infection, but this does not seem to exist in your case.

It is quite common for the itching and discomfort to last for a few days, in spite of the cure. If it is too annoying, you could ask your doctor to prescribe a cortisone-based ointment with a higher concentration, and for the itchiness, you might consider (obviously only on prescription) an anesthetic cream for local use (xylocaine or lidocaine based).

What do I need to know about diving with a cold sore?
Here are a few issues you should consider
  • Sun exposure or mechanical trauma from the mask and/or regulator may worsen the wound, creating a larger scab and lengthening the healing process.
  • If the sore is bleeding, oozing or otherwise open, the risk of infection by pathogens in the water is significant. Cold sores can become complicated by bacterial infections, so it is important to wash them thoroughly with soap and water and keep them as clean and as dry as possible.
  • If a mask skirt will be placed over the sore in a way that rubs or irritates it, then diving should be postponed. The same is true of the regulator; if holding it would cause irritation, then diving would not be recommended.
  • Dive buddies should review procedures for buddy breathing in an out-of-air situation in light of the fact that cold sores are contagious. If gear is rented, ensure proper decontamination procedures are followed. Although it's unlikely, there is always a chance that resuscitation may be needed. Thus, precautions should be taken to prevent disease transmission. This is normally not an issue because barrier devices are readily available in most first aid kits.
  • Treatments such as penciclovir (Denavir) and docosanol (Abreva) can soften the skin and promote healing. Topical numbing agents such as phenol and menthol may be used for comfort. See your doctor and begin using an over-the-counter product at the first sign of a cold sore; beginning antiviral therapy within the first 48 hours can speed recovery. We recommend you to go back to diving once the treatments are over, there are no more signs and symptoms related to the cold sore and there is total recovery of the ideal psycho-physical conditions.

Can I dive with hypertension?
Basically, an increased blood pressure or hypertension is not a contraindication for recreational diving. However, it is important how pronounced the increased blood pressure is and whether there are already typical consequential damages as can be caused by longer existing hypertension.

Since in most cases an increased blood pressure requires treatment with medication with partly possible significant undesirable side effects, it first needs to be determined whether these medications are compatible with recreational diving.

I underwent a tympanoplasty (repair of ear drum perforation) and mastoidectomy (removal of infection from the bone behind the ear) surgery 4 weeks ago. When can I start diving again, or should I stop diving now?
Operative procedures in the area of the middle ear can lead to very different conditions regarding ventilation. A mastoidectomy is an extremely complex surgery. While after most interventions involving a tympanoplasty diving fitness can be quickly re-established in case of a robust eardrum, which needs to be determined by an ENT doctor, a mastoidectomy has a minimum healing phase of 8 to 12 weeks.

After this, again, an ENT doctor has to decide whether diving can be resumed.
The altered anatomy of the ear after complete healing absolutely necessitates the precise examination by a specialist who tests the endurance and equalization capacity in such cases. 

I regularly suffer from a headache after diving. I do not suffer from migraine and do not suffer from a headache when I do short dives. What can be wrong?
Chronically recurrent headaches after long dives can have numerous causes.

Most are:

  1. Accumulation of carbon dioxide in the blood caused by wrong breathing techniques. These headaches are very severe and last quite a long time.
  2. Unfavorable diving position with overextension of the cervical spine. Often hardening of the neck muscles can be found.
  3. Biting the mouthpiece of the regulator too hard can lead to overstressing the chewing and postural neck muscles and can therefore also lead to severe headaches, which should, however, resolve swiftly after the dive.

I understand that feeling tired after a dive may be a symptom of decompression sickness, but I almost always feel tired after diving. Should I be concerned?
The expectation of normal (i.e., nonpathological) tiredness following diving varies from person to person. Factors such as individual fitness, thermal stress, gear constriction, diving skill, work completed during the dive, psychological stress (positive or negative) and distraction can all affect how tired one feels.

While these variables make it difficult to quantify tiredness as a symptom of decompression sickness (DCS), unusual fatigue has long been documented in association with other symptoms of DCS.

The mechanism behind fatigue as a symptom of DCS remains elusive, although it is possibly a response to a cascade of physiological events taking place in various tissues.
It could be through direct stimulation of nervous tissues or indirectly through the stimulation of other tissues. It is possible that the attention currently being directed toward identifying biochemical markers of DCS will help resolve the questions.

In the meantime, it is reasonable to say that DCS represents a complex, multifocal response to a decompression injury. Unusual or “undue fatigue” (that in excess of normal fatigue for a given individual and diving exposure) is a recognized symptom.

When trying to provide rescue breaths in the water to an injured diver, why can’t I use my spare regulator’s purge button? That seems easier to me than trying to manage a pocket mask
Using the purge button of a second-stage regulator has been proposed many times, but any advantage it may seem to offer does not outweigh the potential risks and complications. If the regulator mouthpiece is not already in the unconscious diver’s mouth, trying to replace it can be difficult and time consuming.

Without a good seal and a means to occlude the diver’s nostrils, any attempts to ventilate will be unsuccessful. Even if the mouthpiece can be successfully placed in the diver’s mouth there is a risk of it pushing the relaxed tongue to the back of the throat and blocking the airway.
If the regulator mouthpiece remained or was placed in the diver’s mouth without blocking the airway, the next challenge would be administering air.

Purge buttons do not have any true regulatory capability. They effectively override the second stage’s function of stepping down gas from intermediate pressure to ambient pressure and thereby deliver intermediate-pressure gas directly from the first stage.
Delivering breathing gas to the lungs at too high a pressure may overinflate them, potentially leading to serious injury.
If the diver’s airway is not maintained in an open position, the breathing gas delivered by the purge button could be forced into the stomach, causing gastric distention.
This places the diver at risk for regurgitation, which can further compromise the airway and lead to aspiration.

Delivering rescue breaths using a pocket mask or similar method provides tactile feedback via changes in pressure required to ventilate the lungs; supplying rescue breaths with the purge valve eliminates this important feedback. Using a regulator’s purge valve also precludes the option of supplementing the gas with 100 percent oxygen.
Rescue methods that are currently taught by dive-training agencies are the result of years of practical experience.
Purge valves were never designed to function as rescue equipment. When ventilating an injured diver, rely on established methods

My doctor recently put me on Coumadin. Could diving while taking this medication cause me any problems?
There is a well-recognized risk for uncontrolled bleeding in people who are being treated with anticoagulant medications such as Coumadin. However, many people who take anticoagulants — including divers — have carefully adjusted their prothrombin times and with appropriate behaviors may not be at undue risk.

Some physicians believe diving is an unnecessary risk for their patients who are taking anticoagulants and will advise against diving, but DAN is unaware of any data indicating that sport divers face an increased risk of complications. 

Some physicians trained in dive medicine may be willing to endorse recreational diving for these patients provided:

  • The underlying disorder or need for anticoagulants does not put the patient at increased risk of an accident, illness or injury while diving
  • The patient understands the risks and modifies his or her dive practices to reduce the risk of ear, sinus and lung barotrauma as well as physical injury. This includes avoiding forceful equalization — equalization must come easily for these people
  • The patient dives conservatively, planning short, shallow profiles to reduce the risk of decompression illness, which can involve bleeding in the inner ear or spinal cord
  • The patient avoids diving in circumstances in which access to appropriate medical care is limited
  • DAN medics are available for consultation with you or your doctor; don’t hesitate to give us a call

After a recent dive, I surfaced and noticed that my eyes were bloodshot and I had two black eyes. Have you ever heard of this?
Like the air spaces in our sinuses and ears, we must also equalise the air space in our masks as we descend. Failure to equalise the air space by exhaling through the nose can create a negative pressure within the mask.

The negative pressure, in effect, creates suction. This is referred to as “mask squeeze”, which can cause varying degrees of  barotrauma to the soft tissues of the face and eyes.
The soft tissue around the eyes swells (periorbital edema) and discolours, manifesting as redness or bruising (ecchymosis). The eyes themselves may appear bloodshot. Unless there is eye pain or visual problems present, there is no specific treatment for facial barotrauma.

The injuries from a mask squeeze can take up to two weeks or more to resolve. The body will eventually reabsorb the ecchymosis and edema. The individual’s appearance may worsen before improving.

A physician or an eye specialist should immediately address any eye pain or visual disturbances, such as blurred vision or partial loss of the visual field. These symptoms are rare with mask squeeze.
The best treatment for mask squeeze is prevention. Exhaling through the nose during descent (as done naturally, for example, with the Valsalva equalisation technique) will minimise the risk of facial barotrauma.

I've recently been diagnosed with Raynaud's Syndrome. I'm an avid diver. Can I continue diving?
Raynaud's Syndrome decreases effective blood flow to the extremities, most significantly fingers and toes; this results in cold, pale fingers and toes, followed by pain and redness in these areas as blood flow returns.

The underlying problem is constriction of the blood vessels in response to cold, stress or some other phenomenon supplying these areas.
Symptoms are often mild.
Raynaud's phenomenon may occur as an isolated problem, but it is more often associated with autoimmune and connective tissue disorders such as scleroderma, rheumatoid arthritis and lupus. Raynaud's Syndrome poses a threat to a diver who is so severely affected that he/she may lose function or dexterity in the hands and fingers during the dive. If coldness is a trigger that causes symptoms in the individual, immersion in cold water will likely do the same.

These individuals should avoid diving in water cold enough to elicit symptoms in an ungloved hand.
The pain may be sufficiently significant that, for all practical purposes, the diver will not be able to use his/her hands. Less severely affected individuals may be able to function adequately in the water. Calcium channel blockers may be prescribed for individuals with severe symptoms; lightheadedness when going from a sitting or supine position to standing may be a significant side effect.

My wife and I love to travel to exotic destinations, and my previous doctor used to give me antibiotics in case I got sick in a remote location. I have a new primary care physician who is hesitant to do this. What does DAN recommend?
For some time now prescribing guidelines regarding antibiotic use for various conditions have favored a much more conservative approach due to increasing antibiotic resistance. Many illnesses are viral in nature, and antibiotics are of no benefit in these cases.

If you get sick while traveling, a local physician is your best resource; he or she will be aware of the common pathogens that cause problems in the area you are visiting.
When traveling, your best defenses against illness are handwashing, careful sourcing of water and food, getting relevant travel immunizations and taking appropriate precautions in areas where mosquitoes and other living organisms can transmit infectious diseases to humans. Talk to your doctor or visit a travel medicine clinic if you will be going to a region in which medical care is lacking.

The doctor can advise you about any medications you should take with you and when to use them.

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