Acute sinusitis: symptoms, how long it lasts and when antibiotics help

The sinuses are small, empty spaces behind your cheekbones and forehead that connect to the inside of the nose. In sinusitis the lining of these spaces swells, which the NHS says stops mucus draining properly into the nose and throat and makes you feel blocked up. It is common after a cold or flu.

NICE Clinical Knowledge Summaries sort acute sinusitis by how long it lasts: acute viral sinusitis lasts less than 10 days; acute post-viral sinusitis means symptoms worsen after 5 days or persist beyond 10 days but for less than 12 weeks; and a secondary bacterial infection develops in about 0.5 to 2 percent of people with acute viral sinusitis. Anything lasting 12 weeks or more is treated as chronic sinusitis, covered on a separate page.

The NHS lists the main symptoms as:

• Pain, swelling and tenderness around the cheeks, eyes or forehead.

• A blocked or runny nose.

• A reduced sense of smell.

• Green or yellow mucus from the nose.

• A high temperature.

The NHS adds headache, toothache, bad breath, cough and a feeling of pressure in the ears, and says you may snore at night and sound nasal when you speak. Young children may be irritable, have difficulty feeding and breathe through their mouth.

Because toothache can be a feature of sinusitis, and a dental infection can mimic it, NICE tells prescribers to consider alternative diagnoses such as a dental infection when symptoms worsen rapidly or significantly.

The NHS says mild sinusitis can usually be treated at home by getting plenty of rest, drinking plenty of fluids, taking painkillers such as paracetamol or ibuprofen (not aspirin for children under 16), avoiding things that trigger allergies, not smoking and cleaning the nose with a salt water solution. Its recipe uses cooled boiled water with salt and bicarbonate of soda, sniffed gently into one nostril at a time over a sink, up to 3 times a day with a freshly made solution each time.

If you have a high temperature or feel too unwell for normal activities, the NHS suggests staying at home and avoiding contact with other people until you feel better.

The NHS says antibiotics are rarely needed because sinusitis is usually caused by a virus, not bacteria. NICE guideline NG79 is explicit: for people with symptoms for around 10 days or less, do not offer an antibiotic prescription, and explain that the usual course is 2 to 3 weeks and that medical help should be sought if symptoms worsen rapidly or significantly, do not improve after 3 weeks, or the person becomes systemically very unwell.

For people whose symptoms have lasted around 10 days or more without improvement, NICE says to consider either no antibiotic or a back-up prescription to use if there is no improvement within 7 days or if symptoms worsen rapidly. It notes that antibiotics make little difference to how long symptoms last or the proportion of people who improve, and that possible side effects include diarrhoea and nausea. An immediate antibiotic is recommended for anyone who is systemically very unwell, has signs of a more serious illness or is at high risk of complications.

The NHS says a pharmacist or GP may prescribe steroid nasal sprays or drops to reduce swelling in the sinuses, and antihistamines if an allergy is causing symptoms. NICE says that for symptoms lasting around 10 days or more, a clinician may consider a high-dose nasal corticosteroid for 14 days in adults and children aged 12 and over, noting this is an off-label use, that it may improve symptoms but is not likely to affect how long they last, and that it can be difficult to use correctly. Take any such medicine only as prescribed or advised by a pharmacist.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you or a child are very unwell, painkillers do not help or symptoms get worse, or you have a weakened immune system, for example because of chemotherapy. NICE recommends hospital referral if sinusitis comes with severe systemic infection, or with complications involving the eye socket or the brain.

Eye-socket signs include swelling or cellulitis around the eye, a displaced eyeball, double vision, restricted eye movement or newly reduced vision; signs involving the brain include swelling over the forehead bone, symptoms of meningitis, severe frontal headache or focal neurological signs. If any of these appear, call 999 or go to A&E.

The NHS says a pharmacist can give the same treatments as a GP for sinusitis, and suggests seeing a GP if you do not get better after 7 days of treatment from a pharmacy or GP, do not improve after 3 weeks of treating symptoms yourself, keep getting sinusitis, or the patient is aged 11 or younger. A GP may refer to an ear, nose and throat (ENT) specialist after 3 months of treatment without improvement, if sinusitis keeps coming back, or if symptoms are only on one side of the face. A private ENT appointment is another route to a specialist opinion, particularly for recurrent problems; the same questions about diagnosis and the evidence for any procedure apply.