Yes, my son still has to do the long-term treatment to keep his odor away because when he stops, the odor begins to return slowly but surely. Also, salt-water fish produces the intense odor in him. Fresh water fish, at smaller amounts at a time, is OK. Too large a ration of fish per meal can produce odor in him.
It's interesting that you mention allergies, and that you're going to be tested for allergies on Monday. When his extreme odor started at the age of 14 (he's now 22 years old) my son's allergy test showed that had such exteme allergies to almost everything (environmental and foods). His allergist said that he was the most allergic patient they had ever had in their long practice, and that it ws a miracle that he was still alive as a result. His odor was so bad, that it filled up their office in a matter of minutes with just his presence. Everyone smelled it.
I also have autoimmune diseases such as Rheumatoid Arthritis for the past 16 years, allergies (environmental and foods)on and off, and asthma with constant rhinitis since birth. I wonder how much of it is a result of, or aggravated by, my gut dysbiosis and leaky gut syndrome. I recently had a few serious cases of MRSA earlier this year and last year, and I had to have extremely high doses of the strongest sulfur based Antibiotics (intravenously and orally) for the longest time, and then I rebuilt my gut with probiotics. I don't know if it was a coincidence or not, but I believe that my Rheumatoid Arthritis went into remission since this last episode.
I am still trying to make sense of all of this, and I guess only more time and research will tell.
Please let us know how your allergy tests show. There might be a very strong link between some of the causes or antigens in gut dysbiosis and leaky gut syndrom and dysfunctional immune systems.