Workup for Excessive Sweating (Hyperhidrosis)
All patients presenting with excessive sweating require a systematic laboratory evaluation to exclude secondary causes before assuming primary hyperhidrosis, as treatable conditions like thyroid disease and diabetes are frequently missed. 1, 2
Initial Laboratory Testing
Order the following tests for every patient with hyperhidrosis 1, 2:
- TSH and free T4 (hyperthyroidism is a major cause) 1, 2
- Hemoglobin A1c (diabetes affects thermoregulation) 1, 2
- Complete blood count 1
- Complete metabolic panel (includes calcium for pheochromocytoma screening) 1, 2
- Serum calcium levels 2
- Vitamin D level 2
- Iron studies 2
Focused History Elements
Systematically assess for secondary causes by asking about 2:
- Medications: Anticholinergics, dopamine-reuptake inhibitors (ADHD medications), diuretics, oral retinoids, antipsychotics 2
- Timing: Night sweats suggest malignancy (lymphoma, leukemia, lung cancer); sweating during sleep indicates secondary hyperhidrosis 2, 3
- Distribution: Generalized sweating points to secondary causes; focal bilateral symmetric sweating (axillae, palms, soles, craniofacial) suggests primary hyperhidrosis 3
- Associated symptoms:
Physical Examination Priorities
- Hypertension and tachycardia (pheochromocytoma, hyperthyroidism) 4
- Thyroid enlargement or nodules 2
- Signs of heart failure (cardiovascular disease causes diaphoresis) 2
- Obesity (increases sweating through mechanical friction and inflammation) 2
- Neurological findings (Parkinson's disease, stroke, autonomic dysfunction) 2
Additional Screening
- Sleep disorders: Screen for sleep apnea, which triggers excessive sweating 2
- Psychiatric assessment: Social anxiety disorder can manifest as hyperhidrosis in anxiety-provoking situations 2
Critical Pitfalls to Avoid
Do not assume primary hyperhidrosis without completing the full workup 1, 2. The most commonly missed treatable causes are:
- Thyroid dysfunction (readily treatable) 1, 2
- Diabetes mellitus 1, 2
- Medication-induced hyperhidrosis (review all medications) 2
- Pheochromocytoma (requires specific screening with calcium levels and clinical assessment) 4, 1, 2
When to Refer
Consider specialist consultation when 5:
- Endocrinology: Abnormal thyroid function, diabetes, suspected pheochromocytoma 2, 5
- Neurology: Signs of Parkinson's disease, stroke, multiple sclerosis, or other autonomic dysfunction 2, 5
- Cardiology: Evidence of heart failure or significant cardiovascular disease 2
Severity Assessment
Once secondary causes are excluded, use the Hyperhidrosis Disease Severity Scale to grade tolerability and guide treatment decisions 3. This validated survey assesses how sweating impacts quality of life and work function 3.