Hyperhidrosis is a functional disorder of the sweat system characterized by excessive sweat production, far exceeding the physiological needs for thermoregulation. Far from being a mere discomfort, this condition can have a significant impact on quality of life, affecting physical, psychological, and social well-being. Although common, it is often underdiagnosed, mistakenly trivialized, or confused with normal sweating related to stress, heat, or physical exertion. Understanding the mechanisms of hyperhidrosis, its clinical forms, potential causes, and available treatments helps guide patients toward appropriate and effective management.
Sweating is a natural phenomenon essential for maintaining the body’s thermal balance. It is ensured by two types of sweat glands: eccrine glands, which are spread across the skin and produce a watery sweat to dissipate heat, and apocrine glands, located mainly in the armpits and groin, which secrete a thicker sweat often associated with body odor.
In hyperhidrosis, this regulatory mechanism malfunctions, either for no apparent reason or disproportionately. The sympathetic nervous system, which controls sweat secretion via acetylcholine, becomes overactive, inappropriately stimulating the glands. This results in abundant, sometimes uncontrollable sweating, which can be localized or diffuse, occurring independently of climate conditions or physical activity.
Sweating is regulated by a coordinated system of organs and neural circuits, with the hypothalamus acting as the conductor. This structure, located at the base of the brain, functions as an internal thermostat. It continuously receives signals about body and environmental temperature (heat, emotions, activity) and adjusts the sweat response accordingly.
The hypothalamus sends commands via the sympathetic autonomic nervous system, which stimulates eccrine sweat glands distributed in the dermis. In response to acetylcholine released at nerve endings, these glands secrete sweat onto the skin surface.
It is important to note that, unlike most structures innervated by the sympathetic system, sweat glands are not activated by adrenaline but by acetylcholine, a so-called “parasympathetic” neurotransmitter. This neurobiological peculiarity partly explains the possibilities for targeted treatments, including botulinum toxin (Botox).
It is important to distinguish two main clinical entities: primary hyperhidrosis and secondary hyperhidrosis.
Primary, or essential, hyperhidrosis is the most common. It appears during adolescence or early adulthood, without any identifiable underlying pathology. It is usually focal, meaning limited to specific areas of the body: the palms, soles, armpits, face, or even the scalp. This form is often symmetrical, bilateral, and exacerbated by stress or emotions; it does not occur during sleep. There is frequently a hereditary component, suggesting a genetic predisposition.
Secondary hyperhidrosis appears later, sometimes abruptly. It is generally generalized and results from an identifiable medical disorder: endocrine conditions (hyperthyroidism, diabetes, pheochromocytoma), chronic infectious diseases (tuberculosis, HIV), paraneoplastic syndromes (lymphoma), or adverse drug effects (antidepressants, hypoglycemic agents, opioids). This form requires a thorough etiological investigation, as treatment primarily focuses on addressing the underlying cause.
Far from being trivial, hyperhidrosis can become socially disabling. It affects interpersonal relationships, self-image, professional life, and in some cases, leads to significant psychological withdrawal. Patients with hyperhidrosis may avoid physical contact, change their clothing choices, fear public speaking or handshakes, and sometimes develop anticipatory anxiety that worsens the condition.
Beyond the emotional impact, hyperhidrosis causes concrete physical inconveniences: skin maceration, irritation, fungal or bacterial infections, difficulty gripping objects, slipping in shoes, or disruption of makeup and hairstyles. Yet many patients hesitate to discuss it with their doctor, either due to unawareness of available treatments or feelings of embarrassment.
The diagnosis of hyperhidrosis is primarily based on patient history and clinical observation. The physician focuses on specifying the onset, frequency, locations, and context of excessive sweating. Validated questionnaires, such as the HDSS (Hyperhidrosis Disease Severity Scale), help assess the patient’s perceived discomfort.
In cases of secondary hyperhidrosis, additional tests may be indicated: hormonal assays, infectious work-up, thoracic or abdominal CT scans, depending on the clinical orientation. The Minor test, using iodine and starch, allows objective visualization of areas with excessive sweating, particularly before treatment with botulinum toxin.
Hyperhidrosis affects up to 3 % of the general population, across all age groups. Yet, fewer than one in four patients consults a doctor spontaneously for this reason. Lack of awareness about therapeutic options, the intimate nature of the symptom, and the social normalization of sweating partly explain this delay in seeking care.
It is essential for physicians to ask their patients about excessive sweating, especially when it affects quality of life. Patients, in turn, should know that there are now concrete, safe, and effective solutions capable of restoring both comfort and self-confidence.
In most cases, primary hyperhidrosis—that is, hyperhidrosis not linked to any underlying pathology—does not resolve spontaneously over time. Although it may fluctuate during certain life periods (puberty, stress, hormonal changes), it tends to persist into adulthood and can sometimes worsen if left untreated.
However, some patients may notice a gradual improvement with age, particularly around their forties, when sympathetic nervous system activity slightly decreases. This, however, remains unpredictable and not systematic. In cases of secondary hyperhidrosis, linked to an identifiable medical cause (such as a thyroid disorder or drug effect), the condition may resolve once the underlying cause is treated.
It is therefore not recommended to wait for spontaneous resolution: early management significantly improves quality of life and prevents the development of lasting psychological impact.
Primary hyperhidrosis has a well-established hereditary component, although the precise genetic mechanisms are not yet fully understood. It is estimated that 30 to 50 % of affected individuals have a direct family history (parent, brother, or sister) with the same condition.
It does not follow a classic Mendelian inheritance pattern, but is likely polygenic, with both genetic and environmental influences. The manifestation of the condition can vary among family members: some may present with axillary hyperhidrosis, others with palmar or craniofacial forms.
The hereditary component explains why hyperhidrosis can appear during adolescence or early adulthood in the absence of any organic pathology. However, having an affected parent does not necessarily mean the condition will develop. Factors such as emotional environment, stress levels, or hormonal profile can also influence its clinical expression.
Hyperhidrosis, although disabling, is not inherently dangerous to general health. Excessive sweating does not reflect overactivity of the heart, kidneys, or metabolism. It does not cause chronic dehydration or electrolyte depletion, at least in moderate forms.
However, it can lead to dermatological complications :
It is also responsible for significant psychological distress, causing social anxiety, withdrawal, and sometimes major professional or emotional impact. For this reason, although it is not life-threatening, hyperhidrosis deserves active medical management, if only to preserve self-esteem and quality of life.
Exercise naturally stimulates sweating to allow thermal regulation. However, in patients with hyperhidrosis, this reaction may become disproportionate and even uncomfortable. This does not mean that exercise should be avoided, on the contrary, good physical fitness helps regulate the autonomic nervous response and can even improve emotional tolerance to the condition.
On the dietary side, certain foods or stimulating substances can temporarily increase sweating : spices, coffee, tea, caffeine-containing drinks, alcohol, very hot dishes.
In the context of established hyperhidrosis, it may be wise to avoid these foods during flare-ups or before delicate social situations. A balanced diet and proper hydration promote better adaptation of the sudoriferous system.
Article written by Dr Romano Valeria
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