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A blocked, painful, pressure-filled face that won't shift is the hallmark of sinusitis. Most cases clear without antibiotics, here's how to treat it, and when you genuinely need a prescription.
Sinusitis (also called rhinosinusitis) is inflammation of the sinuses, the four pairs of air-filled spaces behind your forehead, cheeks, nose, and eyes. Normally, your sinuses produce mucus that drains freely into your nose, helping keep it clean and free of germs. When the lining swells, usually after a cold, those drainage openings get blocked, mucus becomes trapped, and the resulting build-up of pressure causes the facial pain, congestion, and other symptoms of a sinus infection.
Sinusitis is grouped both by how long it lasts and by what's causing it:
| Type | How long it lasts | Usual cause |
|---|---|---|
| Acute | Less than 4 weeks | Viral (e.g. the common cold) |
| Subacute | 4 to 12 weeks | Lingering viral or bacterial |
| Chronic | 12 weeks or more | Often bacterial, allergies or structural |
| Recurrent | Several short episodes a year | Varies, worth investigating |
Most cases are viral. Bacteria can cause sinusitis directly or take hold after a viral infection, often the explanation when symptoms last beyond about 10 days or get worse after first improving. Fungal sinusitis is less common and usually more serious, mainly affecting people with a weakened immune system.
Sinusitis is most often set off by the viruses that cause colds and flu, but bacteria, fungi, and allergies can all trigger it too. Some people are more prone to it than others. Common risk factors include:
Sinusitis itself isn't contagious, but the viruses and bacteria that can cause it are, so a cold that later develops into sinusitis can spread to others, especially in the early days. Wash your hands regularly, cover coughs and sneezes, and avoid close contact while you're unwell.
Most cases of acute sinusitis are viral and improve within 2 to 3 weeks without antibiotics. Symptoms often peak in the first few days and then gradually settle. A bacterial infection is more likely if symptoms are severe, last longer than about 10 days without improving, or improve and then suddenly worsen (a 'double-worsening' pattern).
Most sinus infections are diagnosed from your symptoms and history alone; no tests are needed. A clinician (or an online prescriber reviewing your questionnaire) will ask how long you've had symptoms, how severe they are, and whether they've followed the typical viral pattern. For persistent, recurrent, or chronic sinusitis, a GP or ENT specialist may look inside the nose with a small camera (nasal endoscopy), arrange a CT scan, or test for underlying allergies to find what's driving it.
Most sinusitis can be managed without a prescription:
A pharmacist can advise on suitable over-the-counter options, including steroid nasal sprays for persistent congestion.
Because most sinus infections are viral, antibiotics usually aren't required and won't speed up recovery. In line with HSE antimicrobial guidance, antibiotics may be considered when:
For the vast majority of people, sinusitis is uncomfortable but harmless and settles on its own. Very rarely, an untreated bacterial infection can spread to the area around the eyes, the nearby bone, or the brain, which is exactly why the urgent warning signs above matter. If you're otherwise healthy and gradually improving, serious complications are very unlikely.
Seek urgent care if you develop swelling or redness around the eyes, severe headache with neck stiffness, vision changes, confusion, or a very high fever, these can signal a rare but serious complication.
If you've had symptoms for more than 10 days with no improvement, or they're severe, a SmartScripts online doctor can assess you for just €20 and prescribe antibiotics or other treatment where appropriate, or advise you on what will actually help.
The vast majority of sinus infections are viral, triggered by a cold, and clear on their own within about 2 to 3 weeks, so antibiotics make no difference and simply expose you to side effects and antibiotic resistance. In line with HSE antimicrobial guidance, antibiotics are generally only considered when a bacterial infection is likely: that is, when symptoms are severe, or you're systemically unwell, when they last beyond about 10 days without any improvement, or when there's a 'double-worsening' pattern where you start to recover and then suddenly get worse again. A clinician weighs how unwell you are and your risk factors before deciding, rather than prescribing automatically.
When antibiotics are genuinely indicated for bacterial sinusitis, amoxicillin is usually the first-line choice, with co-amoxiclav (Augmentin) sometimes used for more persistent or complicated cases, and doxycycline or a macrolide such as clarithromycin used as alternatives for people with a penicillin allergy. The specific antibiotic, dose and duration are decided by a prescriber based on your symptoms, medical history, any allergies and whether you've recently taken antibiotics. You should never self-prescribe or use leftover antibiotics, as the wrong choice can be ineffective and contribute to resistance.
Most cases of acute sinusitis improve within about 2 to 3 weeks, with symptoms often peaking in the first few days and then gradually settling, even without antibiotics. If symptoms drag on, sinusitis is grouped by duration: acute lasts up to around 4 weeks, while anything persisting beyond about 12 weeks, or that keeps recurring, is classed as chronic sinusitis and should be assessed by a doctor, as it may need different treatment or further investigation. As a rule of thumb, if you're not improving after about 10 days, or you get better and then sharply worse, it's worth being reviewed.
Yes. A registered prescriber can assess your symptoms through a short online consultation, for just €20, and if it's appropriate, prescribe treatment the same day, such as a steroid nasal spray for persistent congestion or antibiotics if a bacterial infection is likely. Just as importantly, if your sinusitis looks viral and doesn't need antibiotics, they'll tell you and recommend the measures that genuinely help, such as saline rinses, decongestants, and pain relief. Online prescribing follows the same clinical standards as an in-person visit, so the assessment decides the treatment, not the request.
The classic signs are facial pain, pressure or tenderness around the cheeks, eyes or forehead, often worse when you bend forward, along with a blocked or runny nose producing thick green or yellow mucus, a reduced sense of smell and taste, headache, and a feeling of fullness in the face or ears. Many people also get a cough (frequently worse at night), a sore throat, bad breath, a mild fever, or an aching sensation in the upper teeth. Symptoms usually follow a cold and build over a few days; seek urgent care if you develop swelling or redness around the eyes, a severe headache with neck stiffness, vision changes, confusion or a very high fever, as these can signal a rare but serious complication.
Medical disclaimer: This article is for general information only and is not medical advice. If you are very unwell, breathless, coughing up blood, or worried about a child, an older person or someone with a long-term condition, seek urgent medical help. Prescription-only medicines, including antibiotics, must be assessed and prescribed by a registered doctor or prescriber. Always speak to a healthcare professional before starting or changing treatment.
Last reviewed: 28th June 2026
Get assessed online for just €20. A SmartScripts doctor can prescribe antibiotics or advise on the right treatment if your sinus infection isn't clearing.
Disclaimer: All prescriptions are issued by Irish-registered doctors, subject to clinical suitability. Medication names mentioned are trademarks of their respective owners.
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