EXCESSIVE SWEATING (Hyperhidrosis)

Hyperhidrosis is broadly classified into primary focal hyperhidrosis and secondary generalised hyperhidrosis, each with distinct causes and patterns of occurrence.

• Primary Focal Hyperhidrosis — this form of hyperhidrosis is idiopathic, meaning it occurs without an underlying medical cause. It typically begins in childhood or adolescence and affects specific areas symmetrically, such as both palms or both underarms. Studies suggest that primary hyperhidrosis has a strong genetic component, as it is often seen in multiple family members. Unlike secondary hyperhidrosis, this type does not occur during sleep and is usually triggered by stress, heat, or emotional stimuli.
• Secondary Generalised Hyperhidrosis — this type results from an underlying medical condition or external factors, such as infections, hormonal imbalances (e.g., hyperthyroidism, menopause), diabetes, neurological disorders, or certain medications. Unlike primary hyperhidrosis, secondary hyperhidrosis can cause excessive sweating over larger areas of the body and may also occur during sleep. Managing the underlying condition often helps alleviate the sweating symptoms.

If excessive sweating interferes with daily life, persists despite using over-the-counter antiperspirants, or is accompanied by other concerning symptoms such as sudden onset night sweats or unexplained weight loss, seeking medical evaluation is essential.

Hyperhidrosis is primarily caused by overactivity of the autonomic nervous system, specifically the sympathetic nervous system, which regulates involuntary bodily functions, including sweating. This excessive sweating occurs even when the body does not require cooling, distinguishing hyperhidrosis from normal perspiration linked to heat or physical exertion.

The mechanism behind primary hyperhidrosis

Sweating is controlled by the eccrine sweat glands, which are densely concentrated in the palms, soles, underarms, and face. These glands are activated by signals from the brain via the sympathetic nervous system, a branch of the autonomic nervous system responsible for the body's fight-or-flight response.

• Neurological overactivity — in individuals with primary focal hyperhidrosis, the brain mistakenly sends excessive nerve signals to the sweat glands, triggering disproportionate sweating even in the absence of heat or exertion. The sudomotor nerves, which are responsible for regulating sweat production, are hyperactive, leading to excessive gland stimulation. This hyperactivity is thought to originate in the hypothalamus, the brain region responsible for thermoregulation and autonomic function.
• Genetic influence — research indicates that primary hyperhidrosis is hereditary, with 30–50% of affected individuals having a family history of excessive sweating. The condition follows an autosomal dominant inheritance pattern, meaning that a single affected gene from one parent may be sufficient to cause the disorder. Despite these genetic links, the specific gene responsible for hyperhidrosis has not yet been identified.
• Dysregulation of the sympathetic nervous system — the sympathetic nervous system, which governs the body’s fight-or-flight responses, is overstimulated in people with hyperhidrosis. Acetylcholine, a neurotransmitter that facilitates nerve communication, is overproduced, excessively activating sweat glands. This leads to persistent sweating episodes, even in cool temperatures or at rest.
• Eccrine gland dysfunction — the eccrine glands (responsible for thermoregulatory sweating) are normal in size and number in individuals with hyperhidrosis, but they are overstimulated due to excessive nerve activity. These glands are most responsive in areas where sweating is typically most noticeable; palms, soles, underarms, and face, which explains why hyperhidrosis often affects these regions.

Secondary hyperhidrosis — Excessive sweating caused by other underlying conditions

Unlike primary hyperhidrosis, secondary generalised hyperhidrosis is caused by an underlying medical condition or external factor, leading to excessive sweating over large areas of the body. This form often occurs suddenly and may continue even during sleep.

• Endocrine Disorders
• • Hyperthyroidism — overproduction of thyroid hormones accelerates metabolism, which increases body heat and sweat production.
  • Diabetes — low blood sugar levels (hypoglycaemia) can activate the sympathetic nervous system, triggering excessive sweating.
  • Menopause — hormonal fluctuations, particularly decreasing oestrogen levels, can lead to sudden sweating episodes (hot flushes).
• Neurological conditions — disorders affecting the autonomic nervous system, such as Parkinson’s disease, stroke, or spinal cord injuries, can disrupt sweat regulation. Some cases of head trauma or nerve damage have been linked to excessive or abnormal sweating patterns.
• Infections & chronic illnesses — Tuberculosis, HIV, and other systemic infections can cause excessive sweating, particularly night sweats. Certain cancers, such as lymphoma, may trigger excessive perspiration due to inflammatory and metabolic changes in the body.
• Medications & substances — some prescription drugs, including antidepressants (SSRIs), opioids, pain relievers, and hormonal treatments, list excessive sweating as a side effect. Caffeine, alcohol, and spicy foods can stimulate the sympathetic nervous system, worsening symptoms in individuals predisposed to hyperhidrosis.

Hyperhidrosis is characterised by excessive, uncontrollable sweating that goes beyond what is necessary for regulating body temperature. The condition can affect specific areas of the body (focal hyperhidrosis) or occur more generally (generalised hyperhidrosis). In addition to persistent sweating, individuals may experience a range of physical, emotional, and social challenges. Common signs & symptoms include: 

• Excessive sweating that occurs frequently, even in cool temperatures or at rest.
• Sweating that is localised to specific areas such as the underarms, palms, soles, face, or scalp.
• Visible sweat stains on clothing, often requiring frequent changes of attire.
• Dripping sweat from the hands or face, making daily activities like writing or using a phone difficult.
• Persistent dampness of the skin, leading to discomfort and an increased risk of bacterial or fungal infections.
• Cold and clammy hands or feet, even in normal weather conditions.
• Worsening of symptoms due to stress, anxiety, or nervousness, although sweating may also occur without any clear triggers.
• Irritation and maceration of the skin, leading to redness, peeling, and possible rashes.
• Foul body odour (bromhidrosis) due to prolonged moisture exposure creating a breeding ground for bacteria.
• Difficulty gripping objects due to sweaty hands, affecting tasks like driving, holding a pen, or using electronic devices.

If these symptoms significantly impact your quality of life, seeking professional assessment and treatment can help manage hyperhidrosis effectively.