How allergies can cause headaches
- Congestion and sinus pressure: swelling blocks sinus drainage, causing pressure in the face and forehead.
- Poor sleep: blocked nose, sneezing and coughing at night lead to tiredness and headaches.
- Migraine triggers: allergies and changes in weather or pollen can trigger migraine in susceptible people.
- Medicines: some older antihistamines cause drowsiness; overuse of painkillers causes rebound headaches.
Allergy sinus headache
Pressure-type pain across the forehead, cheeks, between the eyes or in the upper teeth, often worse when bending forward or lying down, together with a blocked or runny nose and other allergy symptoms, suggests an allergy-related sinus headache.
See sinus headache and sinus pressure relief.
Is it really a migraine?
Studies have found that many people who believe they have sinus headaches actually have migraine. Migraine often causes throbbing pain on one side, nausea, sensitivity to light and sound, and can also cause nasal congestion and watery eyes. Migraines last from hours to days and may run in families.
If headaches are recurrent, disabling or come without clear nasal symptoms, migraine should be considered and treated appropriately.
Can allergies cause dizziness?
Allergies can cause light-headedness or a feeling of imbalance when swelling blocks the Eustachian tubes, creating ear pressure and fullness. Antihistamines that cause drowsiness can also make people feel dizzy. True spinning vertigo is less likely to be caused by allergies and should be assessed.
See sinus dizziness and sinus and ear pressure.
Can allergies cause a fever?
Despite the name hay fever, allergies do not cause a true fever. Some people feel hot, tired and achy, but a temperature of 38°C or higher points to an infection such as a cold, flu, COVID-19 or bacterial sinusitis. Allergies can make it easier for sinus infections to develop when congestion persists.
See allergies vs cold.
What helps
- Use a steroid nasal spray daily during your allergy season.
- Take a non-drowsy antihistamine.
- Rinse the nose with saline; see neti pot sinus rinse.
- Apply warm compresses to the face and breathe steam.
- Use painkillers only occasionally to avoid medication-overuse headache.
- Drink enough water and keep regular sleep.
Reducing allergen exposure
- Check pollen forecasts and keep windows closed on high-pollen days.
- Shower and change clothes after being outdoors.
- Reduce dust mites with allergy covers and hot washes.
- Keep pets out of the bedroom.
- Use an air purifier with a HEPA filter if helpful.
When to see an ENT or allergy specialist
If headaches and nasal symptoms persist despite treatment, an ENT specialist can examine the nose and sinuses with a camera, check for nasal polyps, a deviated septum or chronic sinusitis, and arrange allergy tests. Immunotherapy can help severe allergies. A neurologist may be involved for frequent migraine.
Allergy headaches in children
Children with allergic rhinitis may complain of headaches, tiredness and poor concentration at school, often due to poor sleep and mouth breathing. Treating the allergy often improves headaches. Recurrent headaches in children should be assessed by a doctor.
Avoiding medication-overuse headache
Taking painkillers such as paracetamol, ibuprofen or combination products on more than 10 to 15 days a month can cause medication-overuse headache, where headaches become more frequent. If you need painkillers this often during allergy season, focus on controlling the allergy with regular nasal sprays and antihistamines, and talk to a doctor about headache prevention.
When to seek urgent help
- A sudden, severe headache, the worst you have ever had.
- Headache with fever, stiff neck, rash or confusion.
- Swelling or redness around the eye, or vision changes.
- Weakness, numbness or difficulty speaking.
- Headaches that are new, worsening or wake you from sleep.
Key points to remember
- Allergies can cause headaches through congestion, sinus pressure and poor sleep.
- They can cause ear pressure and light-headedness but not a true fever.
- Many “sinus headaches” are migraines.
- Treating allergies and avoiding triggers usually helps.
Questions about allergies and headaches
These answers are general information and do not replace an examination or individual medical advice.
What does an allergy headache feel like?
Pressure across the forehead, cheeks and around the eyes, often with a blocked nose.
Can allergies cause headaches every day?
Persistent allergies can cause frequent headaches, but daily headaches should be assessed.
Can allergies make you dizzy?
They can cause light-headedness through ear pressure; spinning vertigo needs assessment.
Can allergies cause a low-grade fever?
No. A fever suggests an infection.
Do antihistamines help allergy headaches?
They help allergy symptoms, which may ease headaches. Steroid nasal sprays help congestion.
How do I know if it is a migraine or sinus headache?
Migraine often throbs, with nausea and light sensitivity. A doctor can help tell them apart.
Can pollen trigger migraines?
In some people, allergies and pollen may act as migraine triggers.
Can a blocked nose cause a headache?
Yes. Congestion and sinus pressure can cause a dull headache across the forehead and face.
Why do my allergies make me feel tired and foggy?
Poor sleep, inflammation and some antihistamines can cause tiredness and brain fog.
Sources
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.