Pertinent Pearls on Hyperhidrosis

What are the key touchpoints associated with diagnosing and treating hyperhidrosis? Dr. Vlahovic reviewed the high points of the process during the recent AAWP Scientific Conference.

Tracey Vlahovic, DPM, FFPM RCPS (Glasg) began by sharing the website SweatHelp.org, from the International Hyperhidrosis Society. Here clinicians and patients can find timely and targeted information on the condition. Her talk focused on primary focal hyperhidrosis, which she explained has a possible hereditary component and a typical age of onset in the early-to-mid-20s. She added that it is important to rule out other causes, however. Diagnosis takes place when a patient has visible, excess sweating for at least 6 months, with 2 or more other findings including, but not limited to, a bilateral, symmetrical presentation, impairment of daily of activities, and a score of 3 or 4 on the hyperhidrosis disease severity scale (HDSS).

Differential diagnosis of hyperhidrosis, said Dr. Vlahovic, may include pitted keratolysis, erythrasma, bromhidrosis, hyperthyroidism, diabetes, hypoglycemia, menopause, or tinea pedis. Various treatments for hyperhidrosis can include the following:

• Aluminum chloride solution (may compound 15-55% in a 2-6% salicylic acid base)
• Powders
• Oxybutinin and glycopyrrolate
• Iontophoresis
• Sympathectomy (although not recommended for the feet)
• Iontophoresis
• Hypnosis
• Onabotulinum toxin A (Botox, Allergan)

Regarding onabotulinum toxin A, the patient population for which it is most applicable are those that have failed topical medications, failed iontophoresis, failed glycopyrrolate, or those with a strong family history. She pointed out that one should avoid this treatment in those that may have an allergy to the components, or those that have an infection at or near the site of the injection.

One bottle of onabotulinum toxin A has 100 units of a purified protein derived from Clostridium botulinum toxin type A, human albumin, and sodium chloride. The solution is vacuum-dried and frozen without any preservative, Dr. Vlahovic added. The exotoxin is a peptide with a heavy and light chain joined by disulfide bridge. The most accepted characterization of its action is that it binds to local nerve endings, inhibiting acetylcholine release. Therefore, if the eccrine sweat glands are not receiving the nerve messaging, there is no resultant action.

Dr. Vlahovic related that best practices involve keeping the vial refrigerated until time of use, and that expiration is usually around 2 years. When ready to inject, reconstitution should classically take place with sterile preserved saline, but she uses 1% lidocaine, anecdotally relating a longer effect and less pain. She recommended rotating the bottle to incorporate as opposed to shaking. Once reconstituting, it is best to keep the vial refrigerated and use within 6 weeks.¹ 

In 2008, Dr. Vlahovic and team published a case study using 4 mL of the reconstituting agent in the 100 unit vial, equating to 25 units per milliliter, or 2.5 units per 0.1 milliliter.² She then said she uses Minor’s iodine scratch test to identify the most involved surface areas on the feet, which are usually the ball of foot, heel, and digits. She noted that not every patient needs treatment on the arch. She reviewed injection technique pearls, and reminded the audience that administration should be no deeper than 2-3 mm.

References

1. Kim A, Jung J, Pak A. Botulinum toxin type A reconstituted in lidocaine with epinephrine for facial rejuvenation: results of a participant satisfaction survey. Cutis. 2013;Suppl:13-8. PMID: 24308152.
2. Vlahovic TC, Dunn SP, Blau JC, Gauthier C. Injectable botulinum toxin as a treatment for plantar hyperhidrosis: a case study. J Am Podiatr Med Assoc. 2008;98(2):156-9. doi: 10.7547/0980156. PMID: 18347128.