There is any other change in the person's alertness (for example, confusion or seizures).
The person has a fever over 102°F (38.8°C).
You notice symptoms of heatstroke (such as rapid pulse or rapid breathing).
The person's condition does not improve or gets worse despite treatment.
To prevent dehydration:
Drink plenty of fluids every day, even when you are well. Drink more when the weather is hot or you are exercising.
If anyone in your family is ill, pay attention to how much they are able to drink. Pay close attention to children and older adults.
Anyone with a fever, vomiting, or diarrhea should drink plenty of fluids. DO NOT wait for signs of dehydration.
If you think you or someone in your family may become dehydrated, call your provider. Do this before the person becomes dehydrated.
Kenefick RW, Cheuvront SN, O'Brien KK. Dehydration, rehydration, and hyperhydration. In: Auerbach PS. Wilderness Medicine. 6th ed. Philadelphia, PA: Elsevier Mosby; 2012:chap 70.
Padlipsky P. Infectious diarrheal disease and dehydration. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier Mosby; 2014:chap 173.
Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.