Your questions are excellent and frequently asked of many health care professionals. This time of year is a big problem for people who are allergic to ragweed and molds. HOWEVER, on a ship, this problem is usually minimal, because, of course, you are either at sea or in Caribbean regions not usually associated with hayfever. This isn't to say that your fiance may not suffer allergy symptoms....he could be reactive to other allergens present in areas that you will visit.
My first recommendation is that your fiance needs to determine what is really going on. If nasal discharge is discolored yellow-green for longer than three weeks, or he has had a fever associated with the sinus condition, it's not likely just allergies. He might consider seeing a physcian if either of these symptoms has existed, because it just may be a sinus infection. If it truly is allergies, he has two treatment courses that he can try:
1. Over-the-Counter (OTC) Medications
To treat allergies, he sounds like he would need a combination of antihistamine and decongestant. The antihistamine helps to dry up the sinuses and stop post-nasal drip, as well as alleviate the response to allergens. The decongestant help to relieve sinus stuffiness (caused by swelling of the nasal membranes) and pressure. HOWEVER, all OTC antihistamines cause drowsiness, and the decongestants are caffeine-like stimulants. For adults, I usually recommend long-acting (8-12 hour) products like Drixoral or Dimetapp.
2. Prescription antihistamine medications
You have to see a doctor to be able to use these. There are several products available, generally in two product categories: non-drowsy (Allegra and Claritin) and drowsy (Zyrtec). Zyrtec is highly effective against seasonal allergies, but causes drowsiness in about 6-12% of patients. Some poeple don't respond to either Allegra or Claritin. Typically, it's pretty patient-dependent.
For the pain caused by a sinus headache, any of the OTC pain-relief medications (aspirin, acetaminophen, ibuprofen, etc.) should help.
Please remember that all antihistamines need a few days to reach their full effectiveness (stabilizing the walls of mast cells, which release histamine during the allergic response), and probably should be taken regularly through the allergy season(s).
I hope this helps you and your fiance, Trudi. Feeling miserable on a romantic cruise certainly will kill the joy of being together. I hope he feels better, and remind him never to be too shy to ask a health care professional (doctor, nurse, or pharmacist) for help.
I hope you enjoy a happy cruise!
John Burns, R.Ph.