What should you know about mountain fever?

Mountain fever is a fever occurring after mountain travel or exertion and needs context because altitude, infection and heat can overlap. The phrase is not a single diagnosis. Recent location, altitude, exertion, sun exposure, food and water, insect bites and contact with illness help a clinician decide what to check.

A measured fever with cough, sore throat, diarrhoea, rash or urinary symptoms can reflect an infection. Headache, nausea, dizziness, breathlessness or poor coordination after gaining altitude may indicate an altitude-related illness, particularly when symptoms worsen with exertion. Heat illness and dehydration can also cause weakness, headache and nausea, but a fever should not automatically be attributed to altitude. Acute Bronchitis, Bronchiolitis, Brucellosis and COVID-19 are among conditions a clinician may consider according to the history.

Stop strenuous activity, rest in a cool place and drink fluids in small frequent amounts if you can keep them down. Do not climb higher while unwell. Record the temperature, symptoms, travel route, timing of altitude changes, food and water exposures, bites and medicines. Arrange medical advice promptly, especially if symptoms began during travel or continue after returning home; the treatment depends on the cause.

Seek emergency help for severe breathlessness, chest pain, confusion, fainting, inability to walk normally, a seizure, blue lips, repeated vomiting or a rapidly spreading rash. Descend to a safer lower altitude when altitude illness is suspected, but do not delay emergency care. A painful red swollen area or a barking cough with noisy breathing also warrants prompt assessment for problems such as Cellulitis or Croup.

Ask whether testing for infection, dehydration or altitude illness is needed, whether travel-related exposures change the assessment and when it is safe to exercise or travel again. Share your highest altitude, symptom onset and any medicines taken.