Red flag symptoms: Respiratory tract infections

Dr Pipin Singh provides an overview of red flag symptoms associated with respiratory tract infections.

Coloured X-ray showing lobar pneumonia, as a possible cause of RTI (SPL)
Coloured X-ray showing lobar pneumonia, as a possible cause of RTI (SPL)

Red flag symptoms

  • Cough >3 weeks
  • Persistent cough in a smoker
  • Haemoptysis
  • Persistent hoarseness >3 weeks
  • Persistent sore throat
  • Persistent palpable neck lumps
  • Persistent unilateral enlarged tonsil
  • Difficulty completing sentences
  • Difficulty swallowing (particularly own saliva)
  • Shortness of breath
  • Pleuritic chest pain
  • Headache, photophobia and neck stiffness
  • Non-blanching rash
  • Nasal flaring/grunting in babies
  • Recession of intercostal muscles in young children

GPs see a high proportion of patients with respiratory tract infections (RTIs). Reasons for prescribing antibiotics are usually multifactorial.

What appears to be a minor RTI may also be something more complicated. It is important not to miss a serious diagnosis in these common presentations, so a detailed history is essential.

Patient concerns

It is important to understand why the patient is presenting now and what their ideas, concerns and expectations are.

Some might be prompted by public health messages about cough, or a previous untoward experience. Not all patients will want antibiotics; reassurance may be as effective, so it is important to be aware of this expectation.

RTIs in adults can present in many ways. Patients may say: 'It's this cough, I can't sleep', 'I've been coughing up phlegm', 'I have a sore throat', 'I think I have a cold', 'I feel chesty', or 'It's my chest again'.

These are the common scenarios. However, other symptoms, such as dyspnoea or pleuritic chest pain, may be the presenting features.

The first step is to establish the duration of the presenting symptom. Have there been any other associated symptoms? Does the patient feel unwell? Have they had a fever?

A sore throat should prompt questions concerning difficulties in swallowing, eating and drinking, and a history of swollen glands.

Possible aetiologies
  • Bronchogenic carcinoma
  • Pneumonia
  • Peritonsillar abscess (quinsy)
  • Bronchitis
  • Pharyngitis
  • Tracheitis
  • Bronchiolitis
  • Influenza
  • Pulmonary embolus
  • Meningoencephalitis
  • Tonsillar malignancy
  • HIV
  • TB
  • Bronchiectasis leading to recurrent LRTI
  • Pulmonary fibrosis
  • Sarcoidosis
  • Interstitial lung disease
  • COPD
  • Asthma

It may be relevant to ask about symptoms of reflux and a detailed smoking and alcohol history may be appropriate, given the duration of the symptom.

A cough should prompt questions about expectorate, haemoptysis, chest pain, weight loss and dyspnoea. Again, a smoking history may prove vital when establishing the possible differential diagnosis. You may wish to enquire about foreign travel or even a sexual history if TB or HIV is suspected.

Chronic cough raises a number of non-respiratory possibilities. Nasal congestion may prompt questions about possible sinusitis, with a history of facial pain, fever, headache or diplopia.

Paediatric assessment will differ and questions will be more focused on respiratory rate, irritability, feeding, urine output and the presence of a non-blanching rash.

It should also be established whether the immunisation schedule is up to date and whether the birth was complicated or not.

If the child has a fever, then be alert to signs that may prompt urgent referral. It may be useful to refer to the traffic light scoring system.

A past history of one or more chronic conditions may change the management options.

A detailed drug history is essential, establishing whether the patient may be taking any medications influencing the presentation such as immunosuppressants.

Antibiotic prescribing in primary care is under intense scrutiny. It is thought that most RTIs are self-limiting and do not require an antibiotic prescription.

Apply the Centor criteria to help guide your decision in prescribing antibiotics in those patients presenting with acute pharyngitis. 

Consider delayed prescriptions and also utilising patient information leaflets, educating patients on time frames to expect with certain self-limiting conditions. The RCGP TARGET Antibiotic Toolkit guides clinicians on prescribing antibiotics and the cultural influences that impact on antibiotic prescribing.


Examination should include respiratory rate, temperature, oxygen saturations and pulse. BP may or may not be relevant.

Is there any difficulty completing sentences? Examine the pharynx, focusing on the tonsils. Are they present, if so, are they enlarged symmetrically? Is there any exudate? Is there any evidence of quinsy?

It may be necessary to palpate for lymph nodes, focusing on the cervical chain, submental and submandibular nodes.

If sinusitis is suspected, it may be necessary to palpate the sinuses and check for nystagmus. Is there any evidence of meningism?

Paediatric examination will require observation of the chest, looking for any recession, observing the respiratory rate, checking for pyrexia, checking the capillary refill time and a general observation of the child. It is likely that an ENT examination will also be necessary. Consider checking oxygen saturations in a child 

Auscultate the lung fields, listening for any added sounds and for heart sounds to assess the heart rate.

Investigations will be guided by history and examination. However, most GPs will have access to:

  • FBC, U&Es, CRP
  • Plain chest X-ray
  • Peak flow
  • Pulmonary function tests

Further reading

NICE Fever in under 5s: assessment and initial management. May 2013 (updated August 2017). 

NICE Self-limiting respiratory tract infections: antibiotic prescribing overview. August 2012 (updated November 2017).

  • Dr Pipin Singh is a GP in Northumberland

This is an updated version of an article that was first published in September 2014.

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