The same histamine reaction that causes our nasal membranes to become inflamed, irritated, swollen and drown in excess mucus production can happen throughout the gut. An almost universal CF complaint is bloating and our swollen, tender intestines are at fault as much as any gas or fecal material.
A histamine reaction is our allergic response and before antihistamine drugs, it was a powerful deterrent to avoid green peppers or whatever. Mild allergies like hay fever make you miserable but won't kill you in most cases, hence, mild. Fortunately we've had antihistamines for serious allergies and limit mild allergy's symptoms.
Enter antihistamine drugs. Honestly, taking antihistamines is not something that feels right. I hate them and I hate how they make me feel. Benadryl is OK excepting the drowsy factor. But this is my personal experience and most people aren't sensitive to antihistamines. The variety of antihistamines is significant and I felt completely fine with a particular antihistamine given to me several years ago. I don't remember the drug, but there's a lot more than the OTC products.
Using certain drugs for seemingly unrelated uses has been around as long as sick people. A heart drug topically applied to the scalp to regrow hair or an antidepressant that really can help pancreatic pain so why not counteract an irritable bowel with an antihistamine?
Several things make sense. Whether it's Irritable Bowel Syndrome (IBS) or Inflammatory Bowel Disease (IBD), swollen, congested tissue certainly fits a histamine reaction. Antihistamines reverse or normalize the blood flow and stop the inrush of blood cells that result in the miserable inflammation and agitated nerves of an allergic response. Our minor airways and the major ones will swell completely shut during an anaphylactic reaction. The bronchials don't close rather the mucus membranes which can swell from 2 or 3 millimeters to 2 or 3 centimeters in minutes.
Antihistamines shrink swollen membranes in a dehydrating action. Most antihistamines are diuretics and you need more than the usual hydration to counter unintended dehydration. I have had to take antihistamines at various times and the side effects like dehydration and feeling cold usually goes away.
I don't see anything untoward in the idea of treating an allergic response in the intestinal mucosa. It could improve your five year old boy's abdominal comfort. As for calming the sympathetic nerves that feed throughout the gut, why not use an antihistamine?
Logically there's an allergy to something in the gut. GI doctors see our GI problems in the non CF population all the time. Whether the IBD or IBS is a result of CF or alcoholism, the treatment is the same. A psychosomatic disorder of the vagus nerve is a real and common condition that can compound or cause GI problems, mimicking a number of organic issues caused by CF.
Food allergies are real. A higher than usual portion of CFers have gluten or milk allergies and should be given a fair trial by eliminating first one and then the other. The actual percentage of people truly allergic or very allergic like celiac disease is small. Around 50,000 years ago, we began to diversify our diets to include nuts, grains, fruits and vegetables and most people evolved to produce enzymes to process milk protein and the wheat protein or gluten. Even though the chances are slim it's worth onsidering a couple month's trial, first eliminating milk products and then sources of gluten. If it solves the problem, it's an inexpensive experiment.
CFer's GI tracts have all the issues with excess, sticky mucus, sticky food, thick, sticky feces that's determined to block and move poorly through the bowels. My feeling is maldigested foods or nutrient rich feces are the primary source of the intestinal inflammation so many CFers suffer from. I believe that a CFer can limit the amount of abdominal pain and nausea with aggressive attention to properly digested foods.
I have never been prescribed an antihistamine drug for my tender tummy. It isn't a crazy idea.
LL
