What causes excessive sweating of the palms?

Excessive sweating of the palms—clinically termed palmar hyperhidrosis—is a relatively common condition characterized by abnormally increased eccrine sweat gland activity in the hands. It is typically idiopathic (primary), meaning it occurs without an underlying systemic disease, and often begins during childhood or adolescence. Primary palmar hyperhidrosis is thought to result from overactivity of the sympathetic nervous system, particularly the thoracic sympathetic chain, leading to exaggerated sweat responses to emotional stimuli, heat, or even minimal triggers.

In some cases, palmar sweating may be secondary to an underlying medical condition. Potential causes include hyperthyroidism, hypoglycemia, infections (e.g., tuberculosis or HIV), certain malignancies (such as lymphoma), menopause-related hormonal fluctuations, anxiety disorders, or medications—including antidepressants (e.g., SSRIs), cholinergic agents, or withdrawal syndromes (e.g., from opioids or benzodiazepines). A thorough clinical evaluation—including history, physical examination, and targeted laboratory testing—is essential to distinguish primary from secondary hyperhidrosis.

Diagnosis is primarily clinical, though tools like the Hyperhidrosis Disease Severity Scale (HDSS) or gravimetric sweat measurement may aid assessment. Treatment options range from conservative measures—such as aluminum chloride–based topical antiperspirants—to more advanced interventions including iontophoresis, botulinum toxin type A injections, oral anticholinergics (e.g., glycopyrrolate), and, in severe refractory cases, thoracoscopic sympathectomy. Management should be individualized, weighing efficacy, side effects, and patient preference.