Sudden onset head congestion during dive

[boulderjohn]

I have started having a repeated problem that I have never before--a sudden (almost instantaneous) head congestion develop during a dive. It is not associated with having a cold or allergies (I do get mild seasonal allergies), and I do not take any kind of decongestant while I dive.

It comes on suddently, usually about 3/4 of the way through a dive, often during a multi-level dive's ascent. My nose is totally stuffed up out of nowhere. I have sometimes been able to take my mask off and clear things out, but that is not always successful. When I surface, everything clears out and I am fine. So far I have not had any ear problems associated with it, except as I will note later.

It started about a year ago while diving in Belize. It happened on a couple of dives only, and I did not think much of it. It happened only rarely over the next 10 months or so. During a week I spent in Cozumel about a month ago, it happened on at least half the dives. It has since happened on several freshwater dives in cooler (57 degree) waters.

Lately it has even happened in a swimming pool while I was conducting classes. Once I was about 80% of the way through a refresher class when it happened, and I could not even get to the bottom of a 12 foot pool because of my ears. It happened in my last class as well, although I did not have the ear problems. Once again, in each case, as soon as I was out of the water, my head was perfectly clear.

Any ideas on this?

[cutlass]

I wouldn't so quickly rule out an allergic reaction because causes are so variable and possibly subtle. Any number of substances, environmental conditions, hormonal, autoimmune, emotional states, or lesions could provoke an allergic-like reaction. A history of long-distance travel is always suspicious for exposure to an atypical allergen. What is somewhat puzzling is the apparently quick resolution upon ending the dive and exiting the water. This suggests a possible environmental component; perhaps temperature, pressure, or humidity change. I'd also think about giving my mask and regulator a good cleaning and replacing parts, including hoses.

I'd make an appointment with my regular doc and if nothing obvious is found, would not be surprised by a referral to an ENT and/or allergist.