Minor dehydration from acute gastroenteritis can manifest as dry mouth, sunken eye sockets, headache, dizziness, general fatigue, decreased appetite, and loss of skin elasticity. If symptoms worsen, signs of shock may appear, including reduced total blood volume, renal dysfunction, rapid weak pulse, low blood pressure, cold and wet limbs, and reduced or absent urine output. It is important to seek medical attention promptly if dehydration symptoms occur and treat according to the type of dehydration, while actively treating the acute gastroenteritis.