This condition is usually exacerbated by emotional causes such as stress, anxiety, fear, or nervousness. This causes excessive sweating on the palms, soles, axillae (armpit), and forehead. It is thought to be associated with an increase in sympathetic out flow from the stress response. It is important to note that sweating is a normal response to stress but people with hyperhidrosis sweat excessively and usually under conditions of low stress that would not usually cause sweating in most people. There are other conditions that my cause this condition such as an injury or disease to the nervous system, diabetes with neuropathy, and parotid gland injury.
Other causes of focal sweating include Compensatory sweating (intense sweating after sympathectomy), osteoarthropathy (palms), blue rubber bleb nevus syndrome, glomus tumors, and pretibial myxedema.