Causes of Secondary Hyperhidrosis: Focal Hyperhidrosis
A variety of diseases can cause localized hyperhidrosis. Neurologic injury and dermatologic syndromes make up the majority of secondary causes of excessive focal sweat production.
Acute spinal cord injury would be expected to lead to loss of sweating below the site of injury, but such injuries can also lead to localized areas of hyperhidrosis seen months to years after the injury. Patients with spinal cord injury at or above T6 can have autonomic dysreflexia, presenting with exaggerated responses to triggers such as bowel and bladder distention, or skin irritation. In addition to excessive sweating on the face and upper part of the trunk, patients also have flushing of the face, nasal congestion, and headache. Orthostatic hypotension occurring in patients with cervical spine injury can trigger a similar exaggerated sympathetic discharge, leading to hyperhidrosis in the face, neck, and upper trunk. Posttraumatic syringomyelia, a fluid-filled cavity in the spinal cord occurring months to years after the acute injury, can also cause focal hyperhidrosis.
Central nervous system injuries such as strokes leading to hemispheric or medullary infarcts can lead to hyperhidrosis on the ipsilateral and contralateral side, respectively.
Injury to the cranial part of the sympathetic chain by accessory cervical ribs can lead to hyperhidrosis on the face, neck, and shoulder. An intrathoracic tumor impinging on the sympathetic trunk or postganglionic nerves can cause hyperhidrosis by a similar mechanism. In reflex sympathetic dystrophy, hyperhidrosis is often seen in the affected area.
When injury occurs to a large portion of the sympathetic chain, either in the spine or in the central nervous system, widespread anhidrosis is common. If this area of anhidrosis is sufficiently large, compensatory hyperhidrosis can occur in innervated areas. Compensatory hyperhidrosis is also seen in diabetic neuropathy, after thoracic sympathectomy (ETS), and in Ross syndrome, a rare syndrome in which anhidrosis occurs in a dermatomal pattern due to focal dysfunction of the sympathetic fibers innervating sweat glands. It should be noted that compensatory sweating after ETS for the treatment of hyperhidrosis has been reported as potentially being as severe or more severe than the original sweating problem and may require treatment in itself. A journal search will reveal the latest on compensatory sweating post-ETS and its management. The risk of compensatory sweating should be weighed prior to ETS and discussed thoroughly with patients.
Two studies published in 2004 demonstrate frequency of compensatory sweating after ETS.
- In a study involving 180 patients with hyperhidrosis, 78% developed compensatory sweating after undergoing ETS, usually affecting the stomach, chest, back, and neck.1d
- In a study of 158 patients who underwent thoracoscopic sympathectomy for primary hyperhidrosis or blushing, or both, compensatory sweating occurred in 89% of patients and was severe enough in 35% that they often had to change their clothes during the day.1e
More recently, attention has been paid to treating compensatory sweating: A study published in 2015 among 62 patients with localized or generalized hyperhidrosis found that low‐dose oxybutynin was effective in reducing symptoms of hyperhidrosis in generalized or localized forms. Side‐effects were frequent but minor and mainly involved dry mouth.1a
Conditions sometimes associated with palmoplantar hyperhidrosis include Raynaud’s disease, erthromelalgia, atrioventricular fistula, cold injury, rheumatoid arthritis, and some rare dermatologic syndromes (see below).
In one type of focal hyperhidrosis, gustatory sweating, increased perspiration occurs on the cheek or mandibular area of the face simultaneously with salivation. This auriculotemporal syndrome, also known as Frey syndrome, has several causes. After inflammation or surgery near the parotid gland, “cross-talk” between regenerating nerves that cause salivation and sympathetic nerves causes excessive facial sweating. High thoracic sympathectomy and diabetic neuropathy involving nerves to the same area can also lead to this syndrome. Foods known to stimulate gustatory sweating include coffee, chocolate, spicy or sour foods, hot foods, alcohol, citric acid, and/or sweets.[19,83,145] There is also an idiopathic variety of gustatory sweating that occurs only with certain foods. A search of the medical literature will reveal numerous studies regarding Frey syndrome and its treatment with practical usefulness for the practitioner in the care of these patients.
1a. Schollhammer M, Brenaut E, Menard-Andivot N, Pillette-Delarue M, et al. (2015). Oxybutynin as a treatment for generalized hyperhidrosis: a randomized, placebo-controlled trial. British Journal of Dermatology, 173: 1163-1168. doi: 10.1111/bjd.13973
1d. Thoracoscopic sympathectomy for hyperhidrosis: indications and results. Doolabh N, Horswell S, Williams M, Huber L, Prince S, Meyer DM, Mack MJ. Ann Thorac Surg. 2004 Feb;77(2):410-4; discussion 414.
1e. Licht PB, Pilegaard HK. Severity of compensatory sweating after thoracoscopic sympathectomy. Ann Thorac Surg. 2004 Aug;78(2):427-31. PubMed PMID: 15276490.