The sinuses are air-filled spaces above, between, and beneath your eyes, flanking your nose. Both the nose and sinuses are lined with a thin membrane that swells and produces mucus in response to irritation. Normally, the mucus from the sinuses drains through small openings, known as ostia, which connect the sinuses to the nasal passages. Sinus headache can occur in three circumstances: when the inner membrane becomes inflamed, when fluid builds up in the sinuses and can’t drain out through the nose, or when pressure in the sinuses is lower than environmental air pressure (sometimes called barometric pressure because it is measured by an instrument known as a barometer). Whatever the cause, sinus headache pain is most often felt in the center of the face, the bridge of the nose, and the cheeks (see Figure 1). It may also occur behind the eyes or the center of the forehead and be accompanied by nasal congestion and clear or opaque nasal discharge.
How sinus headache develops
Any condition that causes the nose or sinus membranes to become swollen can narrow or completely block the ostia — resulting in a sinus headache.
Inflammation of the nose and sinus membranes, known as rhinosinusitis, is usually triggered by allergy or viral infection. Less often, rhinosinusitis is caused by exposure to secondhand smoke, perfume, or other inhaled chemicals.
Sometimes, particularly when the inflammation is sufficient to block drainage from the sinuses, bacteria that normally live in the sinuses take advantage of the situation, producing a bacterial infection (see Figure 8). A bacterial sinus infection not only causes head pain, but also often produces foul-smelling, yellow-green discharge, coughed up from the back of the throat, that can leave a bad taste in the mouth. A bacterial infection can also cause fever, and, at its worst, chills and uncontrollable shaking.
Air pressure inside the sinuses also contributes to sinus headache. Typically, the air pressure inside the sinuses is the same as the pressure in the nose and in the air around you. But blockage of the ostia can result in unusually low air pressure inside the sinuses, which produces sinus pain.
Figure 1: Sinus infection (sinusitis)
Normally, mucus drains from the sinuses into the nasal passages through small openings, known as ostia. But these openings can become blocked from allergy, viral infection, or some other cause. This congestion can lead to a bacterial sinus infection, which is often accompanied by yellow or green nasal discharge, a bad taste in the mouth, and sometimes fever.
Relieving sinus headache
Treating sinus headache depends on what’s causing it. Sinus headaches are usually caused by allergies that lead to inflammation of the nose and sinus membranes and sometimes obstruction of the ostia. In such cases, the best treatment approach is to take a combination of OTC medications. First take an antihistamine to block the action of histamine (a substance released during an allergic reaction that causes mucosal swelling and mucus production). Then take guaifenesin (Mucinex is especially effective), which thins the mucus so that it drains more easily. Another option is a decongestant, which also reduces swelling and opens up the nasal and sinus passages. Such medications, or a steam bath, will usually do the trick.
Yellow or green sinus discharge means you have a bacterial infection, which warrants a call to your doctor. You’ll need an antibiotic and a decongestant, but no antihistamine, to treat this condition. (Antihistamines dry out the mucous membranes and make drainage more difficult. If a decongestant does not offer sufficient relief, ask your doctor about a steroid nasal spray.) To confirm a diagnosis, your doctor may order some diagnostic tests, such as a CT scan. If you develop high fever, severe pain, or chills and uncontrollable shaking, contact your doctor immediately.
Preventing sinus headache
People with allergies seem especially susceptible to sinus headache. Treatment includes antihistamines or corticosteroid nasal sprays. Many antihistamines are available over the counter, but corticosteroids require a doctor’s prescription.
Some antihistamines (both OTC and prescription) can make you drowsy, slow your reaction time, and impair your judgment. The older “first-generation” antihistamines, which are more likely to cause such effects, include chlorpheniramine (Chlor-Trimeton, others), diphenhydramine (Benadryl), clemastine (Tavist), and brompheniramine (an ingredient in the combination product Dimetapp). The “second-generation” antihistamines have fewer side effects — in particular, drowsiness and nasal dryness — than the older ones. These “non-sedating” medicines include loratadine (Claritin, Alavert, others), available over the counter, and fexofenadine (Allegra), desloratadine (Clarinex), and azelastine (Astelin nasal spray), all available by prescription.
However, keep two things in mind. First, if drowsiness is a concern, it’s important to choose your medications wisely. Some first-generation antihistamines cause less drowsiness than others, while some second-generation antihistamines that are promoted as non-sedating still cause drowsiness in some people. For example, although chlorpheniramine causes drowsiness in about 10% of users, it is less sedating than other older antihistamines such as diphenhydramine or clemastine.
The second issue is cost. The newer antihistamines are more expensive than the older ones. For many people, particularly those looking for a cost-saving option, a good strategy is to first try one of the older antihistamines. If drowsiness becomes an issue, you can always switch to a second-generation medication. Another cost-saving option is to take a newer antihistamine during the day (when drowsiness is an issue) and an older medication, such as chlorpheniramine, at night.