What is the recommended treatment for hyperhidrosis axillae using botulinum toxin (Botox)?

Botulinum Toxin Treatment for Axillary Hyperhidrosis

Botulinum toxin type A (BTX-A) is the recommended first-line treatment for axillary hyperhidrosis, with intradermal injections of 50-100 units per axilla providing effective symptom relief for 6-9 months with minimal side effects.

Dosing and Administration Protocol

Recommended Dosage

• For axillary hyperhidrosis:
  • Standard dose: 50-100 units per axilla 1, 2
  • High-dose option: 200 units per axilla for longer-lasting effects (up to 19+ months) 1
  • Different formulations require different dosing:
    • Botox: 50-100 units per axilla
    • Dysport: 150-300 units per axilla (using 1:3 conversion ratio) 3

Administration Technique

• Intradermal injections spaced 1-2 cm apart across the hyperhidrotic area
• Multiple small-volume injections (0.1-0.2 mL per site)
• Target the dermis rather than subcutaneous tissue for optimal effect
• Distribute injections evenly throughout the axillary vault

Efficacy and Duration

• Onset of action:
  • Botox: Typically within 1 week
  • Dysport: Typically within 2 weeks 3
• Duration of effect:
  • Standard dosing: 6-9 months 2
  • High-dose (200 units per axilla): Up to 19-29 months with significantly lower relapse rates (11.8% at 12 months) 1
• Efficacy rate: Nearly 100% of patients experience cessation of excessive sweating within 6 days of injection 1

Safety Considerations

Precautions and Contraindications

• Have epinephrine and antihistamines available during administration 4
• Patients with history of anaphylaxis to botulinum toxin preparations should not receive treatment (1-2% risk of anaphylaxis) 4
• Monitor for potential spread of toxin effect beyond injection site 5
• Use caution in patients with pre-existing neuromuscular disorders or cardiovascular disease 5

Potential Side Effects

• Local pain and burning during injection (most common) 1
• Potential for spread of toxin effect (rare with cosmetic doses) 5
• Serious hypersensitivity reactions (rare but can include anaphylaxis) 5
• No reported cases of muscular weakness, insensitivity, or systemic reactions with proper axillary administration 1

Post-Treatment Care

• Patients should:
  • Remain upright for 3-4 hours after treatment
  • Avoid touching, rubbing, or massaging the treated areas
  • Refrain from strenuous exercise for 24 hours
  • Avoid alcohol consumption for 24 hours
  • Maintain normal facial expressions but avoid excessive movements 4

Treatment Algorithm

1. Confirm diagnosis of axillary hyperhidrosis (excessive sweating confined to axillae)
2. Determine appropriate formulation and dosage:
   • For standard duration (6-9 months): 50-100 units Botox per axilla
   • For extended duration (>12 months): Consider 200 units Botox per axilla
3. Administer via multiple intradermal injections across affected area
4. Monitor for immediate adverse reactions for 30-60 minutes post-injection
5. Schedule follow-up at 2 weeks to assess response
6. Re-treat when effects begin to wane (typically 6-9 months with standard dosing)

Clinical Pearls and Pitfalls

• Important: Different botulinum toxin products are not equivalent and doses cannot be converted between products except with established conversion ratios 5
• Botox has shown quicker onset and longer duration than Dysport at a 1:3 conversion ratio 3
• High-dose treatment (200 units per axilla) significantly prolongs the relapse-free interval without increasing side effects 1
• Repeated treatments show consistent efficacy without evidence of neutralizing antibody development 1
• Skin testing before administration is no longer recommended due to low predictive value 4

Botulinum toxin treatment represents a significant improvement over conventional treatments like topical antiperspirants or iontophoresis, which have limited efficacy, and surgical sympathectomy, which carries higher risks and can cause compensatory hyperhidrosis 6.