Altitude Illnesses take on many forms - not every form  is life-threatening and are treatable or can even be avoided if you are prepared.

• High Altitude Cough – This is thought to be caused by the increased ventilation rates coupled with cold and extremely dry air at altitude. Coughs are common at altitude however, if the cough is persistent and becomes worse, seek medical help as it could be a symptom of HAPE.
• Cheyne Stokes Periodic breathing - This condition can be characterised as alternate rapid breathing and slow shallow breathing including intermittent periods where breathing completely stops. This can lead to interrupted sleep leaving people fatigued despite having thought they slept for the whole night.
• High Altitude Retinopathy – This is a condition in which there is changes to the retina including bleeding, which can lead to a loss of sharp vision. Although common in assents above 4500m a slow ascent can prevent suffering. If you do suffer from this condition it is recommended to descend as in most cases this resolves the issue.
• Snow Blindness – This is an eye condition in which the cornea of your eyes become burnt due to overexposure to UV light that is reflected up off of the snow. The symptoms include blurred vision, sensitivity to light and a headache. An easy way to prevent this condition is to wear good quality wrap-around sunglasses as this will protect your eyes form the UV rays.
• High Altitude Syncope – This can be described as a brief loss of consciousness and can occur in people if they stand up too quickly after arriving at altitude. It is caused by the pooling of blood in the legs and less blood reaching the brain. Almost all recover quickly and do not suffer any more episodes.
• Sunburn – Even at altitude and in the cold, it is possible to get sunburnt, much like when your skiing the snow reflects back the sun and can lead to sunburn. The easiest way to prevent this is to keep well covered and apply sun cream to any exposed areas.
• Peripheral Oedema – This occurs when an excessive amount of fluid accumulates in your tissues, at altitude this is common in the lower legs and hand. This condition can occur when descending from high to low altitude. In most people the swelling subsides by itself but can take up to two weeks.
• Slower wound healing – It is important to bear in mind that when at altitude small cuts and blisters will take longer to heal, therefore make sure they are kept clean and clear of infection to prevent any further problems.

‍References:

Barry, P.W. and Pollard, A.J. (2003) “Altitude illness”, British Medical Journal, 326(7395), pp.915-919.

Bezruchka, S. (2005) Altitude illness: Prevention & Treatment, Seattle: Mountaineers Books.

Luks, A.M., Auerbach, P.S., Freer, L., Grissom, C.K., Keyes, L.E., McIntosh, S.E., Rodway, G.W., Schoene, R.B., Zafren, K. and Hackett, P.H. (2019) “Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update”, Wilderness & environmental medicine, 30(4), pp.3-18.