Pharmacology of Histamine and Mosquito Bites

[Rybee]

Hi All,

I'm travelling over to Asia for a while and whilst the market is flooded with a huge number of anti-histamines, each with their own 'reason for best use' I wanted to know whether anybody could expand upon what exactly happens to the body's immune system when somebody is bitten by a Mosquito, and accordingly, the pharmacological action of various antihistamines which could determine what anti-histamine would be best for me to use against the inflammation, swelling and itching?

Is it just as straight forward as 'any antihistamine will do' or can we delve a little deeper into the pharmacology of why antihistamine X will serve me much better than antihistamine Y? I've seen some nasty, nasty Mosquito bites and if I can understand the science of the reaction behind a bite, hopefully I can pick up exactly what type of antihistamine will serve me best?

So is it really a case of 'any antihistamine will be as good as one another' or that one antihistamine is more selective and will perform significantly better in reducing the red, itchy, swelling sore pussy bites?

 

[serotonin2A]

All antihistamines will block histamine. The important considerations are (1) selectivity, i.e. how likely are they to produce side effects at doses required to block histamine responses, and (2) whether they produce central effects.

 

[Rybee]

So if we were to exclude selectivity central effects, is there one specific antihistamine that would work best at minimising the side effects of a mosquito bite?

 

[Kittycat5]

Probably not. A mosquito bite produces what is called the wheal and flare response. This is what the raised bump and the surrounding redness one gets soon after being bitten. This is caused by a type of WBC cell called mast cells quickly responding to the bite and dumping their contents, of which histamine is a very prominent one, and initiating the immune response. Antihistamines are effective in combating this reaction.

Many people also develop of secondary response mediated by eosinophils and manifests as a papule which kind of resembles a pimple. Eosinophils release different chemicals such as leukotrienes, various interleukins, and TNF-alpha. Antihistamines have very little effect on the pustules, but corticosteroids may.

There is some evidence that among the 2nd generation antihistamines, cetirizine is superior to loratadine at treating the wheal and flare, so perhaps avoiding Claritin in favor of Zyrtec is a good idea.

 

[sekio]

Topical anihistamines with a bit of sodium channel blocking (local anesthetic) effects are good... e.g. diphenhydramine

A better solution is prevention. Load up on DEET or the like.

 

[clubcard]

The African mosquito-traps are simple and work wonders if you are camping, They give off CO2 then, when the mozzie goes for them, it's trapped and drowns.