Which are the causes of Hyperhidrosis?

Hyperhidrosis is a condition characterized by excessive sweating beyond what is necessary to regulate body temperature, categorized into primary focal hyperhidrosis, which has no underlying medical cause, and secondary hyperhidrosis, which is caused by another health condition or medication. While the exact cause of primary hyperhidrosis remains under research, it is believed to involve an overactive sympathetic nervous system, whereas secondary hyperhidrosis is a direct physiological response to external triggers or systemic diseases.

What causes primary versus secondary hyperhidrosis?

To understand the causes of hyperhidrosis, it is helpful to distinguish between its two clinical forms. Primary focal hyperhidrosis typically begins in adolescence and affects specific areas like the palms, soles, or underarms. In this form, the sweat glands are anatomically normal, but the nerves that signal them to produce sweat become overactive. Think of it like a thermostat that is set too low; the body "cools" itself even when it is not overheated. Conversely, secondary hyperhidrosis is a symptom of another process. It often involves generalized sweating across the entire body and is frequently linked to metabolic shifts, hormonal changes, or medication side effects.

Are there genetic factors linked to hyperhidrosis?

Research indicates that genetics play a significant role in primary hyperhidrosis. Studies suggest that approximately 30% to 65% of individuals with primary focal hyperhidrosis report a positive family history, suggesting an autosomal dominant pattern of inheritance with variable penetrance. While no single "sweat gene" has been identified, researchers are currently investigating potential loci on chromosomes that may regulate the sympathetic nervous system's sensitivity. Because this condition is often polygenic, meaning it involves multiple genes, the inheritance pattern is complex and not yet fully mapped by clinical genetics.

What are the common triggers and risk factors?

While primary hyperhidrosis is often idiopathic (meaning the cause is unknown), secondary hyperhidrosis is triggered by identifiable factors. Distinguishing between a cause and a risk factor is vital: a cause (like hyperthyroidism) directly produces the excessive sweat, while a risk factor (like obesity or certain medications) increases the likelihood that the body's cooling system will become overwhelmed.

• Endocrine disorders: Hyperthyroidism, diabetes (specifically hypoglycemia), and menopause-related hormonal fluctuations.


• Medications: Antidepressants (particularly SSRIs), cholinergic agents, and certain blood pressure medications.


• Neurological conditions: Parkinson’s disease or spinal cord injuries that disrupt autonomic signaling.


• Infectious or systemic diseases: Chronic infections like tuberculosis or malignancies such as lymphoma, which often present with night sweats.

Is the etiology of hyperhidrosis fully understood?

The medical community is still actively researching the precise etiology of hyperhidrosis. While we understand the "how"—that the eccrine sweat glands are being overstimulated by acetylcholine released from sympathetic nerve fibers—the "why" remains a subject of intense study. Current research is focused on mapping the neural pathways in the hypothalamus that control autonomic responses. By better understanding these pathways, researchers hope to develop targeted therapies that can "reset" the signaling to sweat glands without the need for systemic interventions.

Next steps

• Consult a dermatologist or a specialist in autonomic disorders to determine if your sweating is primary or secondary.


• Maintain a "sweat diary" to identify specific environmental or emotional triggers that worsen your symptoms.


• Join the Hyperhidrosis community at DiseaseMaps.org to connect with 152+ others who are sharing their experiences and management strategies.


• Discuss blood work with your physician to rule out metabolic causes like thyroid dysfunction or low blood sugar.

Medical disclaimer: This information is for educational purposes only and does not constitute medical advice, diagnosis, or treatment; always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Hyperhidrosis.


• International Hyperhidrosis Society: Clinical guidelines for sweat management.


• Orphanet: Rare diseases and their manifestations.


• PubMed/NCBI: Current reviews on the pathophysiology of primary focal hyperhidrosis.