What is palmar hyperhydrosis?
Palmar hyperhydrosis is a technical term for sweaty palms. This condition is characterized by excessive perspiration in the palm region of the hands. Excessive sweating in any one region of the body is termed as focal hyperhydrosis. Palmar hyperhydrosis is a type of focal hyperhydrosis. Sweaty palms may also be accompanied by sweaty feet, armpits, cheeks, or a general hyperhydrosis where there is excessive sweating all over the body.
Hyperhydrosis is not the same as normal sweating because it is not always triggered by overheating and is also excessive. Sweating is a mechanism for keeping the body temperature under control. The thermoregulatory center in the hypothalamus is responsible for the maintenance of the core body temperature. Hyperhydrosis refers to perspiration that is excessive compared to the amount required for controlling the body temperature.
Symptoms of Palmar Hyperhydrosis
The following are the main signs and symptoms associated with palmar hyperhydrosis:
- Sweaty palms: The key sign of palmar hyperhydrosis is excessive perspiration on the palmar surface. The amount of perspiration may vary on an individual basis, with some individuals exhibiting mild clamminess, whereas others experiencing sweat dripping from the palms. There may also be a temperature difference in the skin of the palms and the skin on other parts of the body.
- Peeling of skin: Excessive perspiration in the palms may also be accompanied by peeling or sloughing skin.
Alternating sweaty and dry periods: Excessive perspiration may not occur all the time in palmar hyperhydrosis. Periods of excessive sweating may alternate with periods of excessive skin dryness.
- Psychosocial symptoms: Psychosocial symptoms are secondary effects of palmar hyperhydrosis. People who suffer from excessively sweaty palms are often unable to do tasks such as handling equipment or holding objects such as pen or cash. Due to potential embarrassment, sufferers may not be willing to shake hands or touch other people. This leads to social awkwardness in both personal and professional life.
Palmar hyperhidrosis can also increase the risk of skin diseases like contact dermatitis and sometimes even skin infections on the palm.
Read more on hand dermatitis.
Causes of Palmar Hyperhydrosis
Production of sweat from the sweat glands in the skin is an involuntary process that is under the control of the autonomic nervous system. The autonomic nervous system is subdivided into two branches:
- sympathetic nervous system
- parasympathetic nervous system
Excessive sweating is caused by the over-activity of the sympathetic branch of the autonomic nervous system. Increased sweat production is caused by stimulation of the sweat glands by nerve impulses. There is no change in the number or size of the sweat glands. Also, apocrine scent glands are not involved in focal hyperhydrosis. Only the eccrine sweat glands are responsible for focal hyperhydrosis.
Excessive sweating in palmar and plantar hyperhydrosis is a vicious cycle. The cooling effect of sweat on the surface of the skin increases sympathetic stimulation through reflex action, leading to production of more sweat.
Emotions can also influence the regulation of sweat production by the autonomic nervous system. Patients who suffer from palmar hyperhydrosis have a normal thermoregulatory system, but have a lower threshold for emotion-triggered sweating.
Hyperhydrosis is generally classified as primary and secondary hyperhydrosis.
Primary hyperhydrosis is localized or focal hyperhydrosis. This condition is also referred to as essential or idiopathic hyperhydrosis because the exact cause is not known. There is usually a family history of primary hyperhydrosis in the affected individuals, who are otherwise healthy.
In addition to palms, sweating may also occur in armpits, face, and feet. Bouts of sweating are usually triggered by strong emotions such as anger, anxiety, fear, and nervousness. Sympathetic nervous system over-activity is responsible for excessive sweat production. Differences in parasympathetic pathways may also be involved. Sweating is significantly reduced during sleep.
Excessive sweating of palms caused by a clearly identified underlying disorder is referred to as secondary palmar hyperhydrosis. Secondary hyperhydrosis usually causes generalized sweating rather than localized perspiration. Conditions that can lead to secondary hyperhydrosis include:
- Hormonal disorders (such as hyperthyroidism, diabetes, thyrotoxicosis, menopause and menstruation)
- Neurological disorders (such as toxic neuropathy)
- Autoimmune disorders (such as systemic lupus erythematosus and rheumatoid arthritis)
- Chronic alcoholism
- Parkinson’s disease
- Plasma cell disorders
- Certain drugs (such as antidepressants and hypertensive medications)
Diagnosis of Palmar Hyperhydrosis
Hyperhydrosis may either be generalized or focal. Focal palmar hyperhydrosis can usually be diagnosed with a case history evaluation. Chronic alcoholism, narcotics addiction, and intake of scheduled drugs may turn out to be some of the trigger factors for palmar hyperhydrosis. The following are the main diagnostic criteria for palmar hyperhydrosis:
- Sweating is bilateral and symmetric in nature.
- Profuse sweating occurs at least once a week.
- A family history of focal hyperhydrosis is usually present.
- Sweating impairs daily activities.
- Sweating episodes begin before the age of 25 years.
- Sweating decreases significantly when one goes to sleep.
Certain medical tests may also be conducted in order to understand the cause of palmar hyperhydrosis. These tests include:
- Hematological studies: Thyroid disorders and diabetes may cause palmar hyperhydrosis. The presence of these conditions can be tested through blood tests for thyroid function and glucose tolerance.
- Imaging: Presence of contributing factors such as pneumonia, tumors, and tuberculosis can be diagnosed through X-rays and MRI scans.
- Electrical conductivity of skin: Sweat reduces the electrical resistance of the skin. Therefore, hyperhydrosis can be detected by a superficial electroconductivity test.
- Thermoregulatory sweat test: A powder that changes color upon coming in contact with moisture can be used to detect focal palmar hyperhydrosis. This procedure is known as the thermoregulatory sweat test.
Treatment of Palmar Hyperhydrosis
The therapy for palmar hyperhydrosis varies with the medical history and the underlying cause. The following are the main treatment options for palmar hyperhydrosis:
- Anticholinergic drugs may be given for their effects on the sympathetic nervous system. However, these drugs have many side effects. Injections of botulinum toxin may also be given in the affected area to reduce local cholinergic activity.
- Activity of sweat glands may be reduced by ionophoresis.
- Management of emotional states such as anxiety, psychological stress, and depression may also help in reducing the sweating associated with palmar hyperhydrosis.
- Surgery is the last option, and can be considered if all other treatment options are ineffective. Surgical treatment involves resection of the sympathetic nerve that supplies the affected area of the skin. However, it is important to note that surgery may worsen the problem in some cases.