Can allergies cause headaches?

Bringing distracting pain and discomfort that can make even basic tasks a challenge, there’s really nothing like a headache to throw your day off course. But, while headache disorders are very common - affecting as many as 9 million South Africans, according to research by the Johannesburg-based Headache Clinic – it can be tricky to determine exactly what is causing yours.

If you suffer from seasonal allergies, you might find yourself asking whether they’re to blame. Since headaches can be linked to an almost endless list of possible triggers – stress, viruses, dehydration, caffeine, alcohol and any number of underlying medical conditions – it’s important to pay attention to the specifics of your symptoms as these can help to determine their most likely cause and find the right treatment. 

A word of caution about rebound headaches

First, a word of caution. It can be tempting to pop a dose of painkillers to treat a headache and get on with your day, but doing this too often can actually cause a vicious cycle in which the painkillers become less effective and so you take more and more potentially habit-forming pills. Not only that, but regular use of pain medication can lead to what is known as a ‘rebound’ or ‘medication overuse’ headache, in which headaches are triggered by the very medication you’re using to treat them.

Could it be a sinus headache?

If you suffer from an allergy or allergies, it is possible that you may be experiencing a sinus headache. This is what’s known as a secondary headache, which means it is caused by an underlying condition – in this case, allergic rhinitis. Secondary headaches are distinct from primary headaches, such as migraines, which are not caused by underlying conditions but are instead considered conditions in their own right. 

Allergies cause inflammation in the body, including in the sinuses, which swell up and produce excess mucus in an effort to flush out the allergen - the substance to which you are allergic. When the sinus cavities become blocked and can’t drain effectively, the pressure that builds up can cause a headache. 

The symptoms of a sinus headache may include:
•    Nagging pain across the nasal area (on either side of your nose, under your eyes).
•    A feeling of pressure or fullness in your cheeks, forehead and brow.
•    Sinus pain that increases in severity over the course of the day. 
•    Sinus pain that gets worse if you lean forward or lie down.
•    Aching in your upper teeth. 

However, it’s important to note that headache specialists consider true sinus headaches to be rare and, contrary to popular belief, that headaches are not a typical symptom of allergic rhinitis.

Is your sinus headache really a migraine?

In fact, some studies have shown that up to 90% of headaches believed to be sinus related are really migraines. This is because there is significant overlap between the symptoms of these two conditions – both may present with tenderness, achiness, congestion and watery eyes and both may worsen with weather changes and exposure to allergens such as pollen – making them easy to confuse.

While it’s very possible to mistake a migraine for a sinus headache, as the treatment for primary and secondary headaches is very different, an accurate diagnosis is crucial.

Generally speaking, migraine symptoms are more intense and may include nausea and/or vomiting and sensitivity to light, two symptoms which are not associated with sinus headaches.

If you regularly have headaches that seem to originate in your sinuses, see a doctor or specialist to rule out migraine as a cause.

Is there a difference between a sinus headache and an allergy headache?

Seasonal allergies can cause a sinus headache as a result of swollen, blocked nasal cavities, but they can also cause an allergy headache. This feels more like a generalised headache, according to the US National Headache Foundation.

There is no formal clinical definition for either sinus headaches or allergy headaches, so these terms are sometimes used interchangeably. The key takeout is that allergies sometimes cause a dull ache in the sinus cavities or a more generalised headache, but you shouldn’t rule out the possibility that your pain or discomfort is coming from another condition – including a migraine.

What are the treatment options for allergy-related headaches?

Antihistamines

Oral antihistamines reduce allergy symptoms by blocking your body’s response to histamine – the substance your immune system produces when you come into contact with an allergen (and which causes allergy symptoms). If your headache is indeed associated with allergies, an antihistamine will bring relief.

Over-the-counter pain relievers

Paracetamol or ibuprofen offer short-term relief for allergy-related headaches, but these should not be used for more than a few days in a row. Never be tempted to increase the recommended dose because your pain is severe or persistent – if that’s the case, seek medical advice.

Nasal sprays

Saline (saltwater) sprays are available over the counter and can help clear your sinuses, thus alleviating headache. Steroid sprays, on the other hand, may require a doctor’s prescription and work by reducing the sinus inflammation that can lead to a headache.

Decongestants

Allergic rhinitis causes the blood vessels in your nasal passages to dilate, resulting in congestion. Decongestants counteract this immune response by causing your blood vessels to constrict. People with certain underlying health conditions, such as diabetes, thyroid disorders and seizures (among others) should avoid using decongestants.

Steroid injections 

In severe cases, doctors may administer a steroid injection to treat seasonal allergies but because these come with a serious risk of side-effects, this is done as a last resort. 
 
Find and order over-the-counter medication for allergy symptoms here. 

Also read: Is it an allergy or a virus?

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