Today's post is dedicated to Mr. S. My sad, sniffly Mr. S, who has welcomed the advent of spring with raucous sternutation. We don't understand it. There's no grass yet, the tree pollen is low. But the poor guy is a mess. And over the weekend, as his playing of Black Ops was continually interrupted by vigorous sneezes, we began to notice a certain amount of diurnal rhythm.
The mornings are the worst, no question. Dawn breaks out, and the tissues do too. He's full of gluey misery until about 11am or so, when things seem to generally quiet down. And then, then comes sundown, and the mucus flows most robustly until poor Mr. S finally passes out in a pile of used tissues. Don't worry, we've got antihistamine and lots of it, but it never gets rid of the symptoms entirely.
But being the scientist that I am, I noticed the pattern, he always seemed less miserable in the middle of the day. But the POLLEN can't be all that much better in the middle of the day, right? And at night, shouldn't it be better? But his allergies are worse! Is this normal? What does it MEAN?
I turned to the lit.
Nicholson and Bogie (a very appropriate name given the subject material...) "Diurnal variation in the
symptoms of hay fever: implications for pharmaceutical development" Current Medical Research and Opinion, 1973.
Note: Thanks to Le Physiologiste for the paper!!
Many of you have probably heard of hay fever. Am I alone in thinking this must have been a specific allergy? I thought if you had "hay fever" you had to be allergic to something specific...like hay (except I figured it wouldn't be hay). I was thinking it'd be something really common like grass or ragweed. But it turns out that hay fever is MUCH less specific than that, and refers just to allergenic rhinitis, the combination of dust or pollen and a sensitized immune system resulting in one very irritated airway.
Symptoms include: sneezing, watery eyes, runny nose (rhinitis), coughing, wheezing, and acute whinging and misery. The inflammatory responses are triggered via the chemical histamine. When we take allergy meds, we are usually taking antihistamines, drugs which act as competitors for the histamine receptors, binding them up so that histamine cannot hit them, and thus saving us some misery. But this means that you'll have the BEST response to the antihistamines if you can get them in your system before the major histamine flood occurs. So you want to take the meds before your symptoms are worst.
But when is that?
To examine this, the scientists called up over 2000 people around the UK, and asked them about their allergies. Did they suffer from hay fever, what was their primary symptom, at what time of day does it begin to bother them, and when were their symptoms worst. And then they came up with maps of where allergies were the worst around the UK, and how they varied over time of day.
It turns out about 12% of people in the UK suffered from hay fever in 1973 (the numbers are apparently lower now, but it's still about 12% in the US). The area with the most allergy symptoms per capita was south east England (the area surrounding London to the south, containing Kent, Sussex, Surrey, Oxfordshire, and other places that I mainly recognize from Jane Austen novels), followed by London itself (smog anyone?), and south west England (with counties like Cornwall, Gloucestershire, and Dorset). The lowest was Yorkshire (which is toward the north of England). You'd think Scotland would be lowest in hay fever, being a bit colder (less pollen?), but no dice.
The biggest symptom of hay fever was sneezing, followed by runny nose, red itchy eyes, wheezing, and coughing came in last. But the time of onset was what I was REALLY after.
You can see above that the allergies really dominated the morning hours, with a big drop around midday, and a small increase at night (though it looks like wheezing and coughing had bigger increases).
The worst intensity graph looks similar.
And it appears that Mr. S's allergies follow the general trend, getting worse in the morning and at night. The authors talk about how formulations of antihistamines should take this into account, releasing most in the morning or at night. Or you could just take the pill right when you get up.
But I still have questions, and my brief search through the literature found me nothing. WHY do allergies have diurnal variation? The morning I understand, all the flowers opening, the breeze picking up, the pollen counts getting high. But doesn't pollen decrease at night? And shouldn't pollen levels be just as bad at midday when the symptoms appear to often be better? What is going on here? Is there diurnal regulation of histamine receptors, getting lower at midday? Or is there diurnal release of histamine itself? Studies on diurnal release of histamine haven't found any changes, so perhaps its the receptors. Is there some other cause? And why haven't people studied this? Or is it just my failed Pubmed-fu?
If anyone wants to pass along an abstract or three, I'd love to see them! In the meantime, I'm putting Mr. S to bed, and he's taking his antihistamine first thing in the morning, to try and head off the sneezing before it starts.
Nicholson PA, & Bogie W (1973). Diurnal variation in the symptoms of hay fever: implications for pharmaceutical development. Current medical research and opinion, 1 (7), 395-400 PMID: 4149254