Hair disorders induced by external factors

• External factors may result in hair loss, increased hair growth, or changes in the color and texture of the hair. • External factors responsible for hair loss are drugs, radiation, traction, fungi, pesticides, plant toxins, heavy metals, and several other chemicals. • Several groups of drugs may be responsible for unintentional induction of hair growth. • Texture and color of hair may be changed by drugs, metals, and ultraviolet and other radiation. • Full recovery is the rule after elimination of the responsible factor