Hyperhidrosis (Excessive Sweating)

Hyperhidrosis is excessive, uncontrollable sweating beyond what is needed for thermoregulation. It can be primary (idiopathic) or secondary (caused by a systemic condition or medication).

Primary:

• Onset / Key Features: Begins in childhood/adolescence; often family history. Sweating is symmetrical and stops during sleep.

• Location: Localized (Axillae, Palms, Soles, Face/Scalp).

Secondary:

• Onset / Key Features: Begins later in life; can be generalised, unilateral, or occur during sleep.

• Location: Generalised 

Associated Conditions/Triggers (Secondary Hyperhidrosis):

• Endocrine: Hyperthyroidism, Diabetes, Menopause.

• Systemic: Infections (TB), Malignancy (Lymphoma).

• Medications: SSRIs, Insulin, Opioids.

Impact (Important in Skin of Colour):

• Visibility: Clothing staining is often more visible on darker clothing worn by individuals with darker skin tones.

• Infections: Recurrent moisture increases the risk of irritant dermatitis, fungal infections (tinea pedis), and bacterial infections (pitted keratolysis).

• Psychosocial Burden: Sweating may be misinterpreted as poor hygiene, leading to a high psychosocial burden.

• General Findings: Visible moisture (sweat beads) on affected areas, clammy soles, damp clothing.

• Skin of Colour Considerations:

  • • Increased risk of Post-inflammatory Hyperpigmentation (PIH) from friction and chronic irritation.

    • Intertrigo and tinea infections in moist skin folds.

    • Pitted Keratolysis (bacterial infection of the soles) may be more visible due to contrast.

• Diagnostic Aid: The Starch-iodine test (Minor test) can be used to easily visualise and localise the areas of excessive sweating.

Management involves avoiding triggers, topical therapy, and advanced treatments for refractory cases.

General Measures:

• Avoid triggers (spicy foods, heat, stress).

• Use loose, breathable clothing.

• Stop causative medications where possible.

Investigations for Suspected Secondary Hyperhidrosis:

• Blood tests: HbA1c, Thyroid Function Tests, CBC, CMP

• Imaging: Chest X-ray (if TB or malignancy suspected).

Treatment Modality:

1. • Topical Antiperspirants: 

     • Description / Mechanism: Aluminum chloride hexahydrate 20% applied at night. The aluminum plug blocks the sweat duct.

     • Skin of Colour Adaptations: Use on completely dry skin and wash off in the morning to minimise irritant dermatitis, which can lead to PIH. Combine with 1% hydrocortisone if irritation occurs.

   • Topical Anticholinergics: 

     • Description / Mechanism: Glycopyrronium wipes (Qbrexza) or Sofpironium gel.

     • Skin of Colour Adaptations:Lower risk of PIH than aluminum salts as they cause less surface irritation.

   • Topical Anticholinergics: 

     • Description / Mechanism: Glycopyrronium wipes (Qbrexza) or Sofpironium gel.

     • Skin of Colour Adaptations:Lower risk of PIH than aluminum salts as they cause less surface irritation.

   • Oral Anticholinergics

     • Description / Mechanism: Oxybutynin or Glycopyrrolate. Used for generalised or when topical fails.

     • Skin of Colour Adaptations: Systemic therapy avoids surface irritation, thus carrying a lower risk of PIH. Side effects include dry mouth, constipation. 

   • Iontophoresis

     • Description / Mechanism: Electrical current drives ions (or water) across the skin barrier. Best for palms and soles.

     • Skin of Colour Adaptations: Effective because it avoids pigmentation complications. Moisturise immediately after treatment to prevent irritant dermatitis.

   • Botulinum Toxin (Botox)

     • Description / Mechanism: Injected to block acetylcholine release, inhibiting sweat glands. Highly effective for axillae, palms, face; lasts 6–24 months.

     • Skin of Colour Adaptations: Excellent option as it avoids pigmentation side effects.

   • Surgery (Last Resort)

     • Description / Mechanism: Endoscopic Thoracic Sympathectomy (ETS) or sweat gland removal (axilla only, e.g., MiraDry).

     • Skin of Colour Adaptations: Must be approached cautiously, as surgery carries a higher risk of keloids or hypertrophic scarring in darker skin tones.

Skinsight – Hyperhidrosis / Excessive Sweating: https://skinsight.com/skin-conditions/hyperhidrosis/

StatPearls (NCBI Bookshelf) – Hyperhidrosis (Brackenrich & Medeus, 2022): https://www.ncbi.nlm.nih.gov/books/NBK459227/

DermNet NZ – Hyperhidrosis (Oakley, 2015): https://dermnetnz.org/topics/hyperhidrosis