Sinusitis - what it is, why it drags on, 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.

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.

You might also get:

• A headache across your forehead
• 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
• 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 does not 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 of your snot 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).

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 (just a bowl of hot water or a long shower), 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.

A word of warning: decongestant sprays like Otrivine are tempting, but don't use them for more than a week. If you do, you'll end up with rebound congestion, and your nose will feel more blocked than before you started.

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 (like mometasone or beclometasone) for about 14 days. 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 usually licensed for hay fever, but it's standard, well-evidenced UK practice. Our pharmacist prescribers can assess you for this online.

When antibiotics actually get used

We keep antibiotics for the minority. If you've got a genuine bacterial picture (persistent beyond 10 days, or the "double sickening") or if you're systemically very unwell, phenoxymethylpenicillin is the first choice. If you can't take penicillin, we look at doxycycline or clarithromycin. But honestly, most people don't fall into this bucket.

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 24/7. 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.