Excessive sweating, also called hyperhidrosis, refers to an overproduction of sweat beyond the normal physiological needs for thermoregulation. This condition, often trivialized, can have a significant impact on patients’ quality of life. There are different forms of excessive sweating, with multiple causes, ranging from neurological and endocrine factors to genetic or emotional origins. Understanding the underlying mechanisms allows for better diagnostic guidance and the proposal of appropriate therapeutic solutions.
Sweating is a natural and vital process, regulated by the autonomic nervous system. It mainly helps maintain body temperature at a stable level (around 37 °C) through the evaporation of sweat produced by the sweat glands. These glands, distributed across the skin, are of two types :
Under normal conditions, the amount of sweat produced is proportional to the body’s thermal needs, particularly during physical activity, emotional stress, or in response to high ambient temperatures. However, in cases of excessive sweating, this regulation is disrupted.
The most common form of excessive sweating is primary or essential hyperhidrosis. It accounts for about 90% of cases and often begins in adolescence or early adulthood, without an identifiable underlying pathology.
In primary hyperhidrosis, the underlying mechanism is an overactivity of the cholinergic sympathetic fibers that innervate the eccrine sweat glands. This overstimulation is most often localized, referred to as localized hyperhidrosis. The most frequently affected areas are the palms (palmar hyperhidrosis), soles of the feet (plantar hyperhidrosis), armpits (axillary hyperhidrosis), face, and scalp (craniofacial hyperhidrosis).
This form of excessive sweating is generally bilateral and symmetrical, worsened by stress or emotion, and tends to decrease during sleep.
Studies have shown that nearly 30 to 50% of people with primary hyperhidrosis have a family history. There appears to be a genetic predisposition, although the gene or genes involved have not yet been formally identified.
Unlike primary hyperhidrosis, secondary hyperhidrosis is the result of an identifiable medical, drug-related, or hormonal condition. It often appears in a generalized form and can occur at any age, even in people without a prior history.
Hormonal imbalances are among the most common causes :
Certain infectious conditions, notably chronic febrile illnesses such as tuberculosis or HIV, can be accompanied by night sweats.
Neurological diseases such as Parkinson’s disease, diabetic autonomic neuropathies, or certain spinal cord lesions disrupt sweat regulation.
Finally, in some cases, excessive sweating can be a paraneoplastic symptom, preceding the discovery of cancer, particularly lymphomas (unexplained profuse night sweats).
Many medications can induce secondary excessive sweating. Among the most frequently implicated :
The consumption of psychoactive substances (alcohol, caffeine, stimulant drugs such as cocaine or amphetamines) can also trigger excessive sweating.
It should be emphasized that stress and anxiety, without being the primary cause, are aggravating factors for excessive sweating, particularly in its primary form. Indeed, eccrine sweat glands are sensitive to adrenaline released during states of psychological tension. This connection explains the worsening of symptoms in emotional contexts: professional interviews, social interactions, or public speaking.
This psychophysiological vicious circle can generate a form of anticipatory anxiety, further increasing sweat production, which often justifies a comprehensive therapeutic approach, including psychological or behavioral support.
Several factors can intensify the manifestations of hyperhidrosis, particularly in its primary form.
The intensity of excessive sweating is not constant : it can vary over days, seasons, or hormonal context, which sometimes makes the disorder difficult to pinpoint. Many patients report more pronounced sweat episodes in summer, during heat waves, or in confined spaces. But beyond external temperature, other factors can exacerbate the symptoms.
Physiologically, periods such as puberty, the menstrual cycle, or menopause are often associated with symptom worsening. This phenomenon is explained by hormonal modulation of the autonomic nervous system, which partly controls sweat gland activity. In some women, unusual sweating before or during menstruation is a recurring symptom. Similarly, hot flashes related to perimenopause can be accompanied by excessive sweating, sometimes mistaken for true hyperhidrosis.
Chronic stress, performance anxiety, or states of psychological hypervigilance also play a role in symptom aggravation. Indeed, the more the patient fears sweating, the more it tends to occur — creating a vicious cycle. This link between the central nervous system and the sudoriferous system is particularly pronounced in palmar or facial hyperhidrosis.
Finally, certain external elements, such as wearing synthetic clothing, consuming coffee or alcohol, or prolonged use of closed shoes, can create a skin environment conducive to more abundant or poorly evaporated sweating. These factors, although not the root cause of the disorder, contribute to its visibility and the discomfort it causes.
Recognizing these aggravating elements allows the patient — alongside medical treatment — to adopt a lifestyle that respects their skin and physiology.
With age, the body undergoes physiological and hormonal changes that can disrupt the thermoregulation system. In women, menopause is often accompanied by hot flashes and night sweats, due to the sudden drop in estrogen levels. In men, andropause can also cause hormonal fluctuations that lead to excessive sweating. Moreover, the higher prevalence of certain chronic conditions in older adults (diabetes, thyroid disorders, cardiovascular diseases), as well as increased medication use, also contribute to this tendency to sweat more.
Sweat secretion is mainly stimulated by acetylcholine, a neurotransmitter of the autonomic nervous system that activates eccrine sweat glands. However, certain hormones play a significant indirect role. Thyroid hormones, by increasing basal metabolism, enhance body heat production and therefore sweating. Adrenaline and noradrenaline, released in response to stress, also intensify sweating, particularly in areas rich in eccrine glands such as the palms and armpits. Finally, the drop in estrogen in menopausal women causes instability of the hypothalamic thermostat, leading to abundant sweating.
Several medical conditions can cause excessive sweating. Hyperthyroidism, by increasing energy expenditure, is a common cause. Chronic infectious diseases such as tuberculosis or HIV can induce profuse night sweats. Lymphomas, particularly Hodgkin’s disease, are known to cause unexplained excessive sweating. Diabetes, especially in cases of autonomic neuropathy, or adrenal tumors such as pheochromocytoma, should also be considered. Identifying the underlying cause is essential to guide treatment.
Certain nutritional deficiencies, although rarely the primary cause of hyperhidrosis, can worsen existing symptoms. A magnesium deficiency, for example, can disrupt autonomic nerve regulation and amplify stress responses, thus promoting increased sweating. Similarly, vitamin D deficiency is sometimes associated with excessive scalp sweating in infants, although this link is less clearly demonstrated in adults. However, excessive sweating should not be attributed to a deficiency without prior medical evaluation.
Drinking water does not directly cause increased sweating, but it plays an essential role in maintaining thermal homeostasis. However, excessive and unjustified hydration can, in some cases, overwork the body’s water elimination mechanisms, particularly through sweat, especially in hot climates or during physical activity. This phenomenon remains marginal: the body sweats to regulate its temperature, not to eliminate excess water consumed.
Stress and anxiety are major factors in amplifying hyperhidrosis, particularly in its primary form. Stimulation of the sympathetic nervous system during emotional tension leads to the release of adrenaline, causing intense activation of the eccrine glands. This often results in localized sweating on the hands, feet, or face. This phenomenon, known as emotional sweating, can be disabling in social or professional contexts, highlighting the importance of an integrated therapeutic approach, sometimes including mind-body support.
Yes, many medications can cause excessive sweating as a side effect. Among the most well-known are antidepressants (notably SSRIs), antipyretics, antihypertensives such as propranolol, and hypoglycemic agents like insulin. Certain hormone treatments, opioids, and anticholinesterase drugs can also be responsible. It is essential, in cases of recent-onset hyperhidrosis, to review all current medications with the prescribing physician.
Primary hyperhidrosis, although present year-round, tends to worsen during the summer due to elevated temperatures and ambient humidity. Thermoregulation is more challenged, increasing sweat secretion. Additionally, emotional sweating is exacerbated by thermal discomfort, particularly in poorly air-conditioned public or professional environments. However, secondary hyperhidrosis does not always have a seasonal pattern and depends mainly on the underlying cause.
Certain foods, known as thermogenic, can increase sweating by stimulating metabolism or causing a vascular reaction. This is particularly true for spicy foods (chili, curry, ginger), which activate TRPV1 receptors involved in the sensation of heat. Caffeine and alcohol are also known to increase sweating due to their vasodilatory effect and stimulating action on the central nervous system. For patients suffering from hyperhidrosis, it may therefore be beneficial to adjust the diet to limit these triggers.
Article written by Dr Romano Valeria
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