Allergy sufferers have lots to deal with already. Rashes, nausea and breathing trouble are just some of the unpleasant side effects of allergies. Now, it seems you can add causing migraines (or worsening them) to the list of possible side effects. A study conducted in 2013 found that allergy sufferers were 33% more likely to suffer from frequent migraines.

If you’re one of the unfortunate group that suffers from both allergies and migraines, here's why this is believed to happen, and what you can do for some relief.

#1: Nasal Allergies

Nasal allergic reactions, including rhinitis and sinusitis, have been the most common cause of migraines. In sufferers who develop sinusitis, this is believed to be directly related to the swelling of irritated and inflamed tissues in your sinuses, which increase pressure on nerves. That pressure then sends signals to your brain, and that results in the familiar and debilitating effects of migraine.

More than a third of all allergy sufferers will also report migraines to their doctors, and only 4% of all migraine suffers don’t report experiencing nasal allergies as part of their medical history. In other words, if you have any sort of nasal or sinus allergy, you either already suffer from migraines, or you are likely to at some point.

#2: Food Allergies

A less direct link exists between food allergies and migraines, but nonetheless sufferers report experiencing a link between certain foods like chocolate and aged cheeses and developing migraine headaches.

Patients typically don’t realize at first that their migraine symptoms are linked to their food, because in most cases, people avoid foods they have a known allergy to. While they may not experience classic food allergy symptoms when eating certain products, however, they might be sensitive to the pharmacological action of those foods. In other words, the chemicals in particular foods act on brain chemistry, which can be a trigger for migraine headaches.

#3: Histamine

Aside from the direct factors of pressure and chemicals in our food, there’s another player in the game of allergies and migraines: histamine.

Histamine is the chemical your own body produces in response to an allergen it believes to be a threat, and it’s the chemical that causes all the trouble. This is the chemical that causes vasodilation, anaphylaxis and hives. Those same visible reactions are likely also happening inside the brain, which can be one of the causes of allergy related migraine, according to allergy researchers.

#4: Indoor Allergens

Many people react badly to common indoor allergens like urine, dried skin flakes, pet dander, cockroach particles, mold and the droppings of dust mites. These can cause a variety of symptoms ranging from hives through nasal congestion, regular headaches and, of course, the dreaded migraine.

Dealing with Allergy Linked Migraines

If you are already receiving treatment for migraines, then hopefully the link between your allergies and your headache has been established, and you’re taking steps to manage both conditions. If you’re one of the many who suffer from so called “sinusitis headaches” or you find that certain foods trigger your migraines, then you might not have made the connection yet. Keeping a headache journal and recording when you suffer a migraine and which external factors might be contributing to your symptoms can be a big help.

As far as limiting the effects of your allergies and hay fever on your head, here’s what you need to know.

• If allergies are causing or worsening your migraines, then the first step you need to take is to control your allergies.
• A trip to an allergy specialist will help you to determine the exact causes of your reactions. Remember that there are thousands of potential causes of allergic symptoms, and you need to narrow down the substances that you should avoid in your environment.
• For sufferers of allergies who are sensitive to airborne allergens, remove carpets in your home, install HEPA filters and take steps to avoid causes, such as feather pillows or pet dander.
• If your migraines are linked to food sensitivity, eliminate common trigger foods like chocolate, cheese, wine and processed foods which contain nitrites. Your doctor can provide a complete list of common culprit food triggers.
• Ask your doctor or allergist about prescription allergy medication or shots, which are more targeted and effective than over the counter antihistamines.

Taking steps to control allergies is likely to reduce the frequency of migraines if they have been a factor in triggering your headaches. Even if you do take all of these steps, however, you may find that you still experience the occasional and debilitating effects of a migraine headache. In that case, specific and specialized treatment for the migraines will be required, and you might need to be prescribed one of the new medications that work to reduce allergy-linked swelling and inflammation.