Hyperhidrosis

N. Solish, MD, FRCPC and C. Murray, MD, FRCPC

Department of Medicine, University of Toronto, Toronto, Canada

Hyperhidrosis is characterized by sweating in excess of the physiological needs to maintain thermal homeostasis. No formal definition exists but for practical purposes any degree of sweating that interferes with activities of daily living, can be viewed as hyperhidrosis. The cause is unknown, however treatment options do exist. This disease is much more common than once thought and greatly impacts upon quality of life (QOL). Treating these patients can be exceptionally rewarding both for the patient and the physician.

Epidemiology and Etiology

In a recent survey of 150,000 households in the US, 2.8% of the population reported having unusual or excessive sweating.[Strutton DR, Kowalski JW, Glaser DA, Stang PE. Presented at the American Academy of Dermatology 61st Annual Meeting, San Francisco CA.] The axilla is the most common affected site, followed by the feet, palms and face. No gender differences were noted and onset typically occurred during childhood or adolescence. The exact cause of focal hyperhidrosis is unknown, although sympathetic overstimulation of normal eccrine glands is the most likely etiology. Interestingly, studies have shown an association between the sympathetic hyperactivity seen in hyperhidrosis with other autonomic disorders such as cardiac hyperexcitability. There is likely also a heritable component to this neurogenic overactivity, as 30%-50% of patients have a positive family history.[Haider A, Solish N. CMAJ 172(1):69-75 (2005 Jan 4).]

Impact on Quality of Life

Hyperhidrosis has a profound impact on social interactions and work related activities. Routine social interactions such as holding hands, shaking hands or hugging become awkward. Patients report a sense of humiliation and embarrassment associated with soaked or stained clothing as well as perceived odours.[Naumann M, Hamm H, Lowe NJ. Br J Dermatol 147:1-9 (2002a); Haider A, Solish N. CMAJ 172(1):69-75 (2005 Jan 4).]

Diagnosis and Patient Evaluation

A history focussing on the location of excessive sweating, duration of the presentation, associated symptoms or comorbidities, family history, age of onset and any specific triggers allows one to differentiate primary from secondary hyperhidrosis. The physical exam will be guided by any suggestion of secondary hyperhidrosis, and will also attempt to confirm the distribution of disease.

Measurement of Hyperhidrosis

Each evaluation should attempt to determine the volume of sweat production, the distribution of hyperhidrosis and the affect on QOL. The starch iodine test provides a qualitative assessment of both volume of sweat production and extent of distribution.

• The area to be tested is dried and an iodine solution (1%-5%) is applied.
• After a few seconds, starch is sprinkled over this area.
• The starch and iodine interact in the presence of sweat to develop a purplish sediment.

This test is most helpful when delineating the area for treatment. To assess impact on QOL, various measures have been validated, such as the hyperhidrosis disease severity scale (HDSS). (Table 2)

Topical Treatments for Hyperhidrosis

Aluminum chloride hexahydrate is considered to be the most effective topical agent for focal, mild axillary hyperhidrosis. It works through mechanical obstruction of the eccrine sweat gland pore. Another topical product is glycopyrrolate, a topical anticholinergic product available as topical pads for mild cases. The main limiting side-effects of all of these products are skin irritation, lack of efficacy in moderate-to-severe axillary hyperhidrosis, and poor response on the palms and soles.

Systemic Treatments

In addition to glycopyrrolate mentioned in Table 5, other agents such as clonazepam, diltiazem, clonidine and nonsteroidal anti-inflammatories have been reported to be useful in isolated cases.

Treatments Considerations with Botulinum Toxin

The main contraindications to botulinum toxin therapy include neuromuscular disorders such as myasthenia gravis, pregnancy and lactation, organic causes of hyperhidrosis, and medications that may interfere with neuro-muscular transmission. [Haider A, Solish N. CMAJ 172(1):69-75 (2005 Jan 4).] Appropriate selection of patients is essential to ensure a satisfactory treatment response and avoid unnecessary frustrations.