DefinitionDehydration occurs when your body does not have as much water and fluids as it should.Dehydration can be mild, moderate, or severe, based on how much of your bodys fluid is lost or not replaced. Severe dehydration is a life-threatening emergency.CausesYou can become dehydrated if you lose too much fluid, dont drink enough water or fluids, or both.Your body may lose a lot of fluid from:Sweating too much, for example, from exercising in hot weatherFeverVomiting or diarrheaUrinating too much (uncontrolled diabetes or some medications, like diuretics, can cause you to urinate a lot)You might not drink enough fluids because:You dont feel like eating or drinking because you are sickYou are nauseatedYou have a sore throat or mouth soresOlder adults and people with certain diseases, such as diabetes, are also at higher risk for dehydration.SymptomsSigns of mild to moderate dehydration:ThirstDry or sticky mouthNot urinating muchDarker yellow urineDry, cool skinHeadacheMuscle crampsSigns of severe dehydration:Not urinating, or very dark yellow or amber-colored urineDry, shriveled skinIrritability or confusionDizziness or lightheadednessRapid heartbeatBreathing rapidlySunken eyesListlessnessShock (lack of blood flow through the body)Unconsciousness or deliriumExams and TestsYour health care provider will look for these signs of dehydration:Low blood pressureBlood pressure that drops when you stand up after lying downWhite finger tips that dont return to a pink color after your doctor presses the fingertipSkin that is not as elastic as normal. When your health care provider pinches it into a fold, it may slowly sag back into place. Normally, skin springs back right away.Rapid heart rateYour doctor may do lab tests:advertisementBlood tests to check kidney functionUrine tests to see what may be causing dehydrationOther tests to see what may be causing dehydration (blood sugar test for diabetes)TreatmentTo treat dehydration:Try sipping water or sucking on ice cubes.Try drinking water or sports drinks that contain electrolytes.Do not take salt tablets. They can cause a serious complication.Learn what to eat if you have diarrhea.For more severe dehydration or heat emergency, you may need to stay in a hospital and receive fluid through a vein (IV). Your health care provider will also treat the cause of the dehydration.Dehydration caused by a stomach virus should get better on its own after a few days.Outlook (Prognosis)If you notice signs of dehydration and treat it quickly, you should recover completely.Possible ComplicationsIf untreated, severe dehydration may cause:DeathPermanent brain damageSeizuresWhen to Contact a Medical ProfessionalYou should call 911 if:The person loses consciousness at any time.There is any other change in the persons alertness (for example, confusion or seizures).The person has a fever over 102 F.You notice symptoms of heatstroke (like rapid pulse or rapid breathing).The persons condition does not improve or gets worse despite treatment.PreventionDrink 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 health care provider. Do this before the person becomes dehydrated.ReferencesChen L. Infectious diarrheal diseases and dehydration. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosens Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier; 2009:chap 171.Greenbaum LA. Deficit therapy. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 54.Santillanes G. Claudius I. Rehydration Techniques in Infants and Children. In: Roberts: Roberts and Hedges Clinical Procedures in Emergency Medicine. 6th ed. Philadelphia, Pa: Saunders Elsevier; 2013:chap 19.Review Date:8/22/2013Reviewed By:Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.