What is the workup and treatment for hyperhidrosis (excessive sweating) of the axillary (underarm) region?

Workup and Treatment for Axillary Hyperhidrosis

For excessive underarm sweating, begin with topical aluminum chloride as first-line therapy, reserving botulinum toxin injection for cases that fail topical treatment or for severe disease. 1

Initial Clinical Assessment

The workup should focus on distinguishing primary from secondary hyperhidrosis:

• Confirm bilateral, symmetric, focal axillary sweating that began before age 25 and occurs at least weekly, as this pattern indicates primary hyperhidrosis 1
• Screen for secondary causes including thyroid dysfunction, medications (anticholinergics, antidepressants), diabetes, infections, malignancy, and neurological conditions 1
• Use the Hyperhidrosis Disease Severity Scale to quantify severity and guide treatment decisions - this validated tool assesses how sweating impacts quality of life and work function 1
• Measure sweat production by gravimetry if available (>50 mg per minute is diagnostic), though this is typically reserved for research settings 2

Treatment Algorithm

First-Line Treatment

Topical aluminum chloride solution (20% in alcohol) should be initiated in most cases of primary axillary hyperhidrosis 1. Apply nightly to completely dry skin, wash off in the morning, and reduce frequency once control is achieved.

Second-Line Treatment Options

When topical therapy fails after adequate trial (typically 4-14 weeks):

• Botulinum toxin A injection (onabotulinumtoxinA) is highly effective and now considered first- or second-line treatment for axillary hyperhidrosis 1, 3

  • Dosing: 50-100 U per axilla, injected intradermally in multiple sites 2
  • Reduces sweat production by 87% at 2 weeks, with effects lasting approximately 24 weeks 2
  • Well-tolerated with 98% patient satisfaction and recommendation rates 2
  • FDA-approved for this indication 4

• Iontophoresis is more appropriate for palmar/plantar hyperhidrosis rather than axillary disease 1

Third-Line Treatment

Oral anticholinergics (glycopyrrolate, oxybutynin) serve as useful adjuncts in severe cases when other treatments fail, though systemic side effects (dry mouth, constipation, urinary retention) limit their use 1, 3

Surgical Options for Refractory Cases

When medical therapies fail:

• Local microwave thermolysis is a newer, minimally invasive option for axillary hyperhidrosis 1
• Ultrasonic surgical aspiration (USA) directly removes sweat glands with 91% success rate and minimal recurrence at 1 year 5
• Local surgical excision of sweat gland-bearing tissue 1
• Endoscopic thoracic sympathectomy should be avoided due to high rates (approximately 50%) of compensatory hyperhidrosis, which patients often find more distressing than the original condition 5

Critical Pitfalls to Avoid

• Do not proceed with sympathectomy without exhausting medical options first - compensatory sweating affects roughly half of patients and can be worse than the original problem 5
• Ensure adequate trial duration of topical aluminum chloride (at least 4-14 weeks) before declaring treatment failure 6, 3
• Screen for secondary causes before labeling as primary hyperhidrosis - thyroid dysfunction and medications are common culprits 1
• Warn patients about potential side effects of botulinum toxin including temporary weakness of nearby muscles, though serious complications are rare in axillary injection 4

Evidence Quality Note

The recommendation for botulinum toxin as highly effective treatment is based on a large multicenter randomized controlled trial showing 87% reduction in sweat production with excellent tolerability 2. This has led to its recognition as first- or second-line therapy in recent clinical reviews 1, 3. Ultrasonic surgical aspiration shows promise with 91% success rates but has less robust evidence than botulinum toxin 5.