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Hyperhidrosis

Definition

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Classification

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Primary (Focal) Hyperhidrosis

Key Features

• Equally affects men and women of all races
• 60-80% have a positive family history - autosomal dominant with incomplete penetrance; locus mapped to chromosome 14q
• Onset: volar (palmoplantar) type often in childhood; axillary type at or after puberty
• Occurs in cold and warm environments; stops during sleep (diurnal only - cortically driven)
• Chronic, unremitting course

Diagnostic Criteria for Primary Hyperhidrosis

1. Focal, visible excess sweating
2. Present for at least 6 months
3. No apparent secondary causes
4. At least 2 of the following:
   • Bilateral and symmetric
   • Impairs activities of daily life
   • At least one episode per week
   • Age of onset <25 years
   • Positive family history
   • Stops during sleep

Sites

• Volar (palmoplantar): Most common - ~50-60% of primary cases. Affects entire palm, sole, lateral aspects and tips of digits. Associated with pitted keratolysis of soles and foul odor.
• Axillary: 30-50% of cases. Right axilla typically produces more sweat than left (60:40). Odor (bromhidrosis) is usually absent as excessive eccrine sweat dilutes odorogenic apocrine secretions.
• Facial: Forehead, cutaneous upper lip; often triggered by emotion.

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Secondary Hyperhidrosis

Causes of Generalized Secondary Hyperhidrosis

• Endocrine: Hyperthyroidism, acromegaly, diabetes mellitus, pheochromocytoma, hypoglycemia, carcinoid syndrome, menopause, pregnancy
• Infections: Febrile illnesses
• Neurological: Parkinson disease, concussion, spinal cord transection, autonomic neuropathies
• Malignancy: Lymphoma, metastatic tumors
• Drugs: SSRIs, tricyclic antidepressants, anticholinesterases (e.g., anti-Alzheimer drugs), opioids, bladder stimulants

Special Forms

• Gustatory hyperhidrosis (Frey syndrome): Sweating of forehead, scalp, upper lip after eating; may be idiopathic or due to parotid surgery, Pancoast tumor, diabetic neuropathy. Occurs in >1/3 of patients after parotid surgery.
• Localized: Over glomus tumors, blue rubber bleb nevus syndrome, POEMS syndrome, complex regional pain syndrome

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Investigation

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Treatment (Step-Ladder Approach)

1. Topical Antiperspirants (First Line)

• Axillae: 10-35% solution applied nightly to a very dry axilla (blow-dried), washed off in 6-8 hours; occlusion generally not required
• Palms: up to 50% concentration, with or without occlusion under plastic gloves
• Once effective, frequency can be reduced to once or twice weekly for maintenance
• Lower concentrations tried first to limit irritation

2. Iontophoresis

• Tap water iontophoresis (Drionic or Fischer unit)
• 20-30 minute daily or twice-daily sessions initially; maintenance intervals can extend to every 2 weeks
• Adding glycopyrrolate 0.01%, botulinum toxin, or aluminum chloride 2% to the medium may accelerate response
• Particularly useful for palmar and plantar hyperhidrosis

3. Systemic Anticholinergics

• Glycopyrrolate, oxybutynin (extended-release), propantheline bromide
• Dose titrated by patient's tolerance vs. response
• Side effects (dry mouth, urinary retention, blurred vision, constipation) often limit use; may aggravate glaucoma
• Effects last 4-6 hours; many patients reserve for social occasions rather than continuous use

4. Botulinum Toxin A (BTX-A) Injections

• All formulations (onaA, aboA, incoA) show similar safety and efficacy; rimaB is effective but causes more pain and systemic adverse events (xerostomia, flu-like symptoms)
• Transient hand weakness (loss of fine motor/pinch strength) is expected for several weeks post-palm injection
• Compensatory hyperhidrosis is not a clinically significant concern (unlike sympathectomy)
• Repeated treatments do not lose efficacy and may increase duration of benefit

5. Energy-Based Devices

• Microwave thermolysis (miraDry): Selective heating destroys eccrine and apocrine glands in the dermis/subdermis. High patient satisfaction; side effects include transient edema, erythema, pain, and longer-term fibrous bands or muscle weakness
• Radiofrequency via microneedles and laser treatment: Appear effective; require more evidence

6. Surgical Options

• Excision of the most active sweating area + undercutting and subcutaneous resection of sweat glands (1-2 cm each side) - virtually always effective
• Liposuction or surgical ultrasonic aspiration of the glands
• In a comparative trial, BTX-A was superior to suction-curettage surgery

• Endoscopic clipping or electrocautery at T3-T5 levels
• Complications (<2% acute): chronic pain, pneumothorax, hemothorax, bleeding, Horner syndrome
• Compensatory hyperhidrosis occurs in up to 1 in 3 patients and can be as debilitating as the original condition - this is the major deterrent
• Gustatory hyperhidrosis is also a known post-operative sequela

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Complications & Comorbidities

• Pitted keratolysis of hyperhidrotic soles (bacterial maceration)
• Tinea pedis / intertrigo: Moisture promotes fungal and bacterial infections
• Contact dermatitis: From topical agents
• Psychological impact: Significant social anxiety, occupational impairment, and quality of life reduction
• Hailey-Hailey disease: Sweating exacerbates this genodermatosis; BTX-A into lesional skin (100 U, 2 U/cm²) can produce clinical improvement

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Key Points Summary