Summary

Hyperhidrosis is a disorder of excessive sweating beyond physiological requirements for thermoregulation. It affects ~3-5% of the population. Primary Focal Hyperhidrosis is idiopathic, bilateral, and typically affects axillae, palms, or soles starting in adolescence. A key diagnostic feature is cessation during sleep. Management follows a strict ladder: Topical Aluminium Salts -> Iontophoresis/Botox -> Oral Anticholinergics -> Surgery (ETS). [1,2]

Clinical Pearls

The "Dry Sleep" Sign: Primary Hyperhidrosis stops during sleep. If a patient complains of "Night Sweats" (waking up soaking wet), this is NOT Primary Hyperhidrosis. It is Secondary to malignancy, infection, or menopause until proven otherwise.

Bromhidrosis: While eccrine sweat is odourless, bacterial decomposition of apocrine sweat causes foul odour (Bromhidrosis). This is a frequent co-morbidity.

Compensatory Hyperhidrosis: The dreaded complication of Thoracic Sympathectomy. The patient stops sweating from hands but sweats profusely from the back, chest, and groin. This is often more distressing than the original condition and is irreversible. Warn patients!

• Observation: Visible dripping sweat. Maceration (soggy white skin).
• Minor's Starch-Iodine Test:
  1. Paint area with Iodine solution (brown). Allow to dry.
  2. Dust with Starch powder (white).
  3. Sweat solubilizes the iodine -> Reacts with starch -> Turns Dark Blue/Black.
  • Usage: Maps the exact area for Botox injections.

• Chronic condition. May improve after age 50.
• Treatments are palliative (symptom control) rather than curative, except surgery (which trades one problem for another).

Key Guidelines

Landmark Evidence

1. Nawrocki et al (JAAD 2019)

• Comprehensive review defining the treatment ladder and efficacy of Botulinum toxin vs topicals.

What is it?

Your sweat glands are working overtime. In most people, they are like a thermostat that turns on when hot. In you, the switch is stuck in the "on" position due to overactive nerve signals.

Is it because I'm nervous?

No. Being nervous makes everyone sweat, and it makes your sweating worse, but the cause is physical (nerves), not psychological.

Treatment

1. Strong Antiperspirants (Driclor): These metal salts plug the sweat holes. You have to use them at night when you are dry, otherwise they sting like crazy.
2. Water Bath (Iontophoresis): For hands and feet, passing a mild electric current through water blocks the sweating for a few days.
3. Botox: We inject the armpits. It blocks the nerve signal to the sweat gland. It works brilliantly but wears off after 6-9 months.
4. Surgery: We can cut the nerve inside the chest. This cures sweaty hands permanently, BUT... most people then start sweating heavily from their back or tummy instead. It's a big gamble.

Common Exam Questions

1. Diagnosis: "Differentiation of Primary vs Secondary?"
   • Answer: Primary stops at night. Secondary (e.g. Lymphoma) causes night sweats.
2. Complication: "Irreversible side effect of ETS?"
   • Answer: Compensatory Hyperhidrosis.
3. Treatment: "First line therapy?"
   • Answer: 20% Aluminium Chloride Hexahydrate.
4. Mechanism: "How does Botox work?"
   • Answer: Blocks Acetylcholine release (SNAP-25 cleavage).

Viva Points

• Gustatory Sweating (Frey's Syndrome): Sweating on the cheek when eating. Caused by aberrant nerve regeneration after Parotid surgery (Auriculotemporal nerve).
• Why apply Driclor at night?: Sweat gland output is lowest at night, allowing the drug to penetrate the duct rather than being washed away.

Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.