Fear relates to the Kidney and consumes Kidney Qi. As children experience fear more intense than adults, fear may manifest in bed-wetting in children as the Kidney is the partner organ of the Urinary Bladder.
Beside Kidney Qi fear also consumes Kidney Essence (learn about Essence in the Vitality chapter). Essence determines the vitality and longevity in every person therefore consumption of Essence by fear may result in premature graying of the hair as the Kidney opens to the hair. Essence on the other hand is part of Yin. Long-term fear may consume Kidney Yin. To learn more about Yin and Yang and their relationship go to the Physiology chapter.
Another way to counteract fear is love. People who are sufficiently loved and/or have developed a loving attitude towards others and themselves are generally fearless.