Sweat glands, called apocrine glands, release their secretions into hair follicles in your armpits, around your nipples, and in your groin. They’re tubular glands that extend below the superficial layer of your skin into the deeper layer and produce a thick, cloudy secretion.
Sweat glands called merocrine glands are more numerous and widely distributed than apocrine glands and are more relevant in PD. Your skin contains almost three million merocrine glands.
Your palms and soles have the highest number of them: 3,000 glands per square inch. Merocrine glands discharge their secretion, sweat, directly on your skin’s surface. Sweat is 99% water, but it contains some salt. Merocrine glands have the following functions:
They cool your skin and reduce your body temperature. When all of your merocrine glands are working maximally, your rate of perspiration may exceed a gallon per hour, and fluid and salt losses can occur. For this reason, athletes in endurance sports must pause frequently to drink fluids.
They provide protection from environmental hazards by diluting harmful chemicals and discouraging growth of bacteria. In PD, increased sweating from merocrine glands may be the result of a malfunctioning ANS, and this may be complicated by anti-Parkinson drugs, especially levodopa/carbidopa.
This is more likely to occur if you’re on a high dose of levodopa/carbidopa and are experiencing “wearing off ” and dyskinesia. In some patients the sweating is dramatic, with a patient having to change clothes several times a day or bedding several times a night. Such patients must be watched carefully and taught to keep up with loss of water and salt.
Sweating may become a problem, although some patients choose not to do anything, because sweating serves a purpose. Other patients apply an antiperspirant, 15% aluminum chloride hexahydrate—obtainable by prescription.
The problem is that an antiperspirant applied to the arm pits and groin blocks sweating from apocrine, not merocrine glands (the main source of sweating). Similarly, Botox injections into the arm pits and groin only block secretions from apocrine glands.
Nonetheless, in some patients this makes a difference. Finally, some patients use a beta-blocker, such as Inderal, that “turns down” the activity of the ANS. Care must be taken because patients who sweat excessively usually have orthostatic hypotension and a beta blocker can aggravate this.
At the Muhammad Ali Parkinson Center, we evaluate each patient who sweats profusely by making certain they don’t have an overactive thyroid gland, diabetes, or are not going through menopause. We then devise a treatment plan that controls the sweating without causing additional problems.