Sinusitis: Symptoms, Causes and What Actually Helps

Sinusitis: Symptoms, Causes and What Actually Helps

A practical UK guide to spotting sinusitis, knowing when to ride it out, and when to actually do something about it.

This is our main sinusitis guide. Looking for treatment? See sinusitis treatment online. All our sinusitis articles are listed in our sinusitis health guides.

If you’ve got that heavy, full ache across your cheeks, your nose is bunged up, and you can’t smell your morning coffee, you’re probably dealing with sinusitis. First off — don’t panic. Most of the time, it’s just a cold that’s overstayed its welcome.

But here’s the thing: we see people in the pharmacy all the time who are convinced they need antibiotics on day three. And honestly? They almost never do. The NHS is trying to curb unnecessary prescribing for a reason. So let’s walk through what’s actually going on in your face, when to sit tight, and when to pick up the phone.

So, what actually is sinusitis?

Put simply, it’s inflammation of the lining of your sinuses. We used to just call it that, but clinicians nowadays tend to say rhinosinusitis because, let’s be honest, your nasal passages are nearly always inflamed at the same time. It’s rare to have one without the other.

Your sinuses are just air pockets in the bones of your face — behind your cheeks, your forehead, and between your eyes. They drain into your nose through tiny little channels that are only a few millimetres wide. You can probably see where this is going: even a small amount of swelling from a cold or allergy blocks those channels completely. Mucus gets trapped, pressure builds up, and that’s when you start feeling like your head is full of cement.

It’s one of the most common things we deal with in UK primary care. And it nearly always comes hot on the heels of a bog-standard cold.

Acute vs chronic — and why the distinction matters

This isn’t just medical jargon for the sake of it. The difference between acute and chronic sinusitis completely changes how we treat it.

Acute sinusitis is short-term. It lasts up to 12 weeks, but in reality, most people are feeling better within two to three weeks. It behaves like an infection.

Chronic sinusitis, on the other hand, is a persistent beast. If you’ve had symptoms continuously for 12 weeks or more, you’re no longer dealing with an infection. You’re dealing with ongoing inflammation. And here’s the kicker: throwing repeated courses of antibiotics at chronic sinusitis is like throwing water at a grease fire — it just doesn’t work. You need long-term steroid sprays, regular saline rinses, and a proper look at underlying causes like allergies or polyps.

If you’re in that chronic camp, our deep dive on acute vs chronic covers the nitty-gritty.

The classic symptoms (and the ones that are emergencies)

The hallmark of sinusitis is that combination of a blocked nose plus facial pain that gets worse when you bend over to tie your shoelaces. Alongside that, a loss of smell is a massive clue. Colds don’t usually steal your sense of smell for days on end; sinusitis does. Facial pressure plus loss of smell is the pairing that separates sinusitis from an ordinary cold more reliably than anything else.

You might also get:

• A headache across your forehead (most “sinus headaches” without a blocked nose are something else: see sinus headache vs migraine)
• An ache in your upper teeth (the roots sit right next to your maxillary sinuses)
• A cough that’s worse at night, from mucus trickling down your throat (post-nasal drip)
• General exhaustion

Less urgent, but still needing same-day advice: if you feel absolutely awful, have a sky-high fever, or have a weak immune system, ring NHS 111 or your GP.

Let’s settle the green mucus debate

I wish I had a pound for every time a patient has said, “But doctor, it’s green, so I must need antibiotics.”

Here’s the reality check: green or yellow mucus doesn't mean you have a bacterial infection. That colour comes from an enzyme in your white blood cells — it simply means your immune system is fighting something. It happens just as readily with a common cold virus as it does with bacteria. GPs don’t look at the colour to decide whether to prescribe; we look at the timeline.

If you’ve been ill for less than 10 days, it’s almost certainly viral. The only time we start genuinely worrying about bacteria is if you hit day 10 with no improvement, or if you were starting to feel better around day 5 or 6 and then suddenly crashed again (that “double sickening” pattern). Our guide to whether a sinus infection is bacterial or viral walks through the signs.

The practical treatment timeline

Days 1 to 10: keep it simple

Honestly, save your money and skip the prescription. For the first week and a half, the best things are cheap and cheerful: saline rinses (using cooled, boiled water, never straight from the tap), steam inhalation (a long shower is safer than a bowl of hot water, particularly around children), and regular paracetamol or ibuprofen to take the edge off the pain. Keep drinking fluids and prop your head up with an extra pillow at night to help things drain. Our guides on how to relieve sinus pressure and how to rinse your sinuses cover the details.

A word of warning: decongestant sprays like Otrivine are tempting, but don’t use them for more than 5 days. If you do, you’ll end up with rebound congestion, and your nose will feel more blocked than before you started. Older packs may still say 7 days, but the MHRA cut the limit to 5 days in April 2026.

Beyond 10 days: the steroid spray step

If you hit the 10-day mark and things aren’t budging, NICE suggests a high-dose steroid nasal spray for 14 days in adults and children aged 12 and over, naming mometasone and fluticasone. This reduces the inflammation in the sinus linings, opening those tiny drainage holes back up. It’s considered “off-label” for sinusitis because these sprays are licensed for hay fever and other conditions, but it’s standard, well-evidenced UK practice. Our guides to mometasone nasal spray and beclometasone nasal spray explain how they're used, and the best nasal spray for sinusitis guide compares them.

When antibiotics actually get used

We keep antibiotics for the minority. If you’re systemically very unwell or at high risk of complications, an antibiotic is started straight away. If symptoms have lasted 10 days or more without improving, NICE suggests no antibiotic or a back-up prescription, used only if things don’t improve or get worse. Where an antibiotic is needed, phenoxymethylpenicillin is the first choice. If you can’t take penicillin, the options are doxycycline or clarithromycin. Phenoxymethylpenicillin, doxycycline and clarithromycin are all 5-day courses. Doxycycline isn’t suitable for children under 12 or in pregnancy, and clarithromycin isn’t used in pregnancy either, so a prescriber will advise on the right alternative. But honestly, most people don’t fall into this bucket. Our guides to antibiotics for a sinus infection and steroid spray vs antibiotics explain how prescribers decide.

If it keeps coming back, look upstream

If you get sinusitis repeatedly, treating each episode individually is like mopping a flooded floor without turning off the tap. The usual culprits are:

• Hay fever or allergic rhinitis: this keeps your nasal lining swollen around the clock. Treating the allergy often reduces sinus infections more effectively than treating the sinus infections themselves.
• Nasal polyps: these soft growths physically block the drainage channels. Suspect them if you have persistent loss of smell.
• Deviated septum: a bend in the middle of your nose that narrows one side.

If you suspect an underlying driver, our hay fever guide is a great starting point.

A quick note on children

Kids get sinusitis too, but it looks a bit different. You’ll often see a persistent night-time cough and a long-lasting runny nose, rather than the classic facial pain adults get. For babies and toddlers, saline drops or sprays are safe and helpful. For older kids (school age and up), you can try a gentle rinse if they can co-operate — but never force it. A proper GP assessment is always the safest route for children, and our guide to sinusitis in children goes further.

UK safety and reporting side effects

Steroid nasal sprays and antibiotics for sinusitis are prescription-only medicines in the UK. Before anything is prescribed, a GPhC-registered pharmacist independent prescriber reviews your consultation, including the other medicines you take. Always read the patient information leaflet in the pack. If you’re prescribed an antibiotic, never share it or keep leftovers for another time: return any unused tablets to a pharmacy.

If you think you have had a side effect from a medicine, tell your pharmacist or doctor. You can also report it to the MHRA through the Yellow Card scheme.

In England, people aged 12 and over may be able to get sinusitis treatment free from a community pharmacy through the NHS Pharmacy First service. Our private online service is for adults aged 18 and over. Our guide to private vs NHS prescriptions for sinusitis compares the two routes.