Causes of Sweaty Hands (Palmar Hyperhidrosis)
Primary vs. Secondary Classification
Sweaty hands result from either primary focal hyperhidrosis (idiopathic excessive sweating without underlying disease) or secondary hyperhidrosis caused by identifiable medical conditions, medications, or systemic disorders. 1
Primary Focal Palmar Hyperhidrosis
Primary palmar hyperhidrosis is the most common cause of sweaty hands and has distinct characteristics:
- Bilaterally symmetric excessive sweating of the palms without an underlying medical condition 1
- Triggered predominantly by emotional stimuli rather than thermal regulation, as it is controlled by the limbic system rather than the hypothalamus 2
- Typically begins in childhood or adolescence and persists throughout life 3
- Not a psychiatric disease despite emotional triggers 4
- Occurs in areas with high density of eccrine sweat glands 3
Secondary Causes Requiring Systematic Exclusion
The most critical diagnostic error is assuming all hyperhidrosis is primary without systematically excluding secondary causes, particularly thyroid dysfunction and diabetes, which are readily treatable. 5, 6
Endocrine and Metabolic Disorders
- Hyperthyroidism (Graves disease): Increases metabolic rate, heat production, and compensatory sweating 5, 6
- Diabetes mellitus (particularly type 2): Affects thermoregulation and autonomic function 5, 6
- Hypoglycemia: Can trigger acute sweating episodes 6
- Pheochromocytoma: Causes episodic sweating with headache, palpitations, and pallor 5, 6
- Carcinoid syndrome: Produces episodic flushing and sweating 6
Neurological Conditions
- Autonomic dysfunction: Disrupts normal sweat regulation 6
- Parkinson's disease: Associated with dysregulated sweating 6
- Stroke: Can cause focal or generalized hyperhidrosis 6
- Spinal cord injury above T6: Causes autonomic dysreflexia with blood pressure elevations and sweating 5
Medications and Substances
- Sympathomimetics: Including decongestants, cocaine, amphetamines, and ephedra cause fine tremor, tachycardia, and sweating 5
- Anticholinergic drugs: Paradoxically affect thermoregulation 6
- Dopamine-reuptake inhibitors (ADHD medications): Impair sweating regulation 6
- Oral retinoids: Can cause hyperhidrosis 6
Other Systemic Conditions
- Malignancies (lymphoma, leukemia): May present with night sweats or generalized hyperhidrosis 6
- Heart failure and cardiovascular disease: May present with diaphoresis 6
- Chronic kidney disease: Causes uremic sweating 6
- Obesity: Increases sweating through mechanical friction and increased pro-inflammatory cytokines 6
- Sleep apnea: Triggers excessive sweating 6
- Social anxiety disorder: Manifests as hyperhidrosis in anxiety-provoking situations 6
Recommended Diagnostic Workup
Laboratory evaluation should include complete blood count, comprehensive metabolic panel, thyroid function tests (TSH, free T4), hemoglobin A1c, serum calcium levels, vitamin D level, and iron studies. 5, 6
Key Diagnostic Steps
- Detailed medication review: Look for anticholinergics, stimulants, and other agents affecting thermoregulation 6
- Pattern assessment: Determine if sweating is focal (hands only) versus generalized, and whether it occurs day and night or only during waking hours 4
- Trigger identification: Emotional versus thermal triggers help distinguish primary from secondary causes 2
- Quantification: Gravimetry (measuring sweat amount) and iodine starch test can document severity and distribution 3
Critical Pitfalls to Avoid
- Overlooking medication-induced hyperhidrosis: Always review the complete medication list including over-the-counter sympathomimetics 6
- Missing thyroid dysfunction: This is readily treatable and should never be overlooked 5, 6
- Ignoring recent illness: Fever or gastrointestinal symptoms significantly impair thermoregulation even after apparent recovery 6
- Assuming psychiatric etiology: Primary focal hyperhidrosis is not generally a psychiatric disease despite emotional triggers 4