Many drinkers report unusual adverse reactions to certain wines. Wines are complex and it's not always easy to identify the source of wine allergies. Trying different wines and noting the differences in the ingredients can help you trace the culprits and avoid the unthinkable solution of cutting out wine altogether.
Sulphites are added to many wines because of their stabilising and preservative powers. Sulphites are also a natural by-product of yeast fermentation, so they are not, arguably, an artificial additive. They can cause severe reactions though, especially for asthmatics. Research by the FDA in the USA showed that about 1% of people are allergic to sulphites. Reactions can be very serious for those who are susceptible, including anaphylaxis.
Yeast allergies will often affect people who have an allergy to mould or fungus. Most wine-makers use brewer's yeast in the fermentation process. If this causes a reaction, it can be worth looking for organic or naturally-produced wines which use the yeasts that form on grape skins.
Histamines are naturally present in red wine and can cause flushing and severe headaches. This affects people in different ways so seems identical to an allergic reaction, although technically it is just a side-effect of consuming histamines, which then trigger the allergic symptoms.
Those people allergic to dairy products should be aware that some winemakers use egg whites and the milk protein casein to clarify and give a rich colour to their wines. These are used in tiny quantities but can still cause allergic reactions.