Red wine headache ("RWH") is a headache often accompanied by nausea and flushing that occurs in many people after drinking even a single glass of red wine. This syndrome can sometimes develop within 15 minutes of consumption of the wine.
The condition does not occur after consumption of white wine or other alcoholic beverages. Some individuals report that they get a migraine headache hours later from drinking some red wines. No one knows for certain why this syndrome occurs. It probably has more than one cause.
Since wines contain a warning label about sulfites many people have assumed that sulfites are the cause of RWH. This is not the case. Almost all wine contains sulfites. Many sweet white wines have more sulfites than red wines. Dried fruit and processed food like lunchmeat have far more sulfites than red wine. Less than 1% of the population is sensitive to sulfites.
Another solution that has been advanced is to drink a cup of black tea before you drink the wine. If one will be drinking over the course of an evening, have another cup or two of black tea during the evening. Quercetin, a bioflavonoid found in black tea, significantly inhibits the headache/flush response (which is an inflammatory effect from histamines), according to Tareq Khan, M.D., a pain expert with St. Luke's Episcopal Hospital in Houston, Texas. Again, if histamine is not the cause of a given individual's reaction to wine, the antihistamine effects of black tea will be of no more help than the antihistamine effects of loratadine, just as in the example of the previous paragraph.
Other experts think tannins are at the root of RWH. Tannins are the flavonoids in wine that give its degree of mouth-drying bitterness. The taste is the same as when you bite into a grape skin. Tannin is a chemical substance that comes from grape skins, stems, and seeds. The skins also impart color to wine, which is why red wines typically have a lot more tannin than whites. Red wines are fermented while in contact with the skins and seeds. Modern winemakers take care to minimize undesirable tannins from seeds by crushing grapes gently when extracting their juice.
Wines can also take on tannins from the oak or other woods used in wine barrels for storage. Different woods in different countries affect the type of tannins in the wine.
Tannins help prevent oxidation, an important role in a wine's aging potential. As age-worthy red wines mature, tannin molecules gradually accumulate and precipitate out of the wine in the sediment.
Certain wine styles have much less tannin content than others, due to reduced maceration time (grape juice contact with the grape pulp, including sources of tannin such as stems, seeds).
French reds from Bordeaux, and Italian reds like Barolo and Barbaresco, are particularly tannic. Vintage port is also very tannic when young, as are wines made from the syrah (shiraz) and cabernet sauvignon grapes.
French reds from Burgundy, and Italian wines like Dolcetto and Barbera, are less tannic. Wines made from Pinot Noir and Sangiovese grapes, as well as Spanish Riojas are less tannic. Beaujolais and Tempranillo are also lower tannin wines.
A quick way to identify these lower tannic wine bottles on a store shelf is to look for the sloped shoulder "Burgundy bottle". This is specially true for European wines, but several new world wineries have also adopted traditional bottle shapes to help consumers distinguish their wines.
There is a difference between the varieties and brands of red wine and the amount one can consume before the headache occurs, but the reports have not been consistent from person to person. Considering how the amount of tannins changes with aging, this would not be surprising.
The Harvard Health Letter notes several well-controlled experiments showing that tannins cause the release of serotonin, a neurotransmitter. High levels of serotonin can cause headaches and that may happen in people who also suffer from migraine headaches. But that does not explain why people who do not get migraines get RWH. Dr. Marion Nestle, chairwoman of the Department of Nutrition and Food Studies at New York University, added that no one complains about tea, soy, or chocolate headaches though all contain tannins.
The tannins that are extracted from grapes found in red wine are primarily condensed tannins which are polymers of procyanidin monomers. Hydrolysable tannins are extracted from the oak wood the wine is aged in. Hydrolysable tannins are more easily oxidised than condensed tannins.
RWH could be caused by the release of prostaglandins which some people are not able to metabolize. Prostaglandins are substances that can contribute to pain and swelling. Ibuprofen (Advil), acetaminophen (Tylenol) and aspirin are prostaglandin inhibitors. Some people get good results taking a dose of an inhibitor an hour before consuming red wine. Aspirin and ibuprofen were shown to be effective at blocking both early and late stages of the RWH, and acetaminophen was effective in blocking the early stage. 
It has also been postulated that RWH could be caused by a strain of yeast or bacteria found in red wine.
RED GRAPE VARIETIES