Tennessee Walker sweating around temple

Question
Dillon, my Tennessee Walker has a small amount of moisture, sweat, unsure what to call it coming out of the temple area on his face.  It looks like he is sweating a little stream of moisture off his face and it trickles down his face, not a lot only a small amount, but on a consitent basis.  This seems odd and my thorobred doesn't do this.  Is it a sweat gland???  Why does it happen even when he is not being worked?

Answer
Dear Julie:

Sorry for the late response. My son had a football game today that was pretty far away. Anyway, interesting problem. Id be interested to know the age of this horse and his health history. No big deal really, but this problem is often a sign of a previous problem encountered some time ago, something you might not have even noticed intitally. This condition is not normal, but is not associated with an aberrant sweat gland or anything else like that.  I believe that in all likelihood, this condition exists as a very localized peripheral neurological problem. We most often see this in association with some other signs that may not be as obvious, such as drooping of the eyelid on the same side, a sunken appearance of the eye itself (sunken into the eye orbit) and occasionally a prolapse of the third eyelid. These conditions, when they occur together, are called "Horner's syndrome". The syndrome is a result of inflammation and ultimately damage and dysfunction of the part of the autonimic nervous system referred to as the sympathetic fibers. In fact, experimental surgical cutting of the "vagosympathitic trunk", the major autonomic nerve fiber bundle in neck, can produce these exact signs.  
Because of the location of the vagosympathetic trunk in the neck next to the jugular vein, in the guttural pouch, and near the inner ear in the skull, this fiber track can be damaged easiy by injections that miss or leak from the jugular vein, by trauma to the neck, infections in the guttural pouch, or trauma or infections that affect the inner ear area or the base of the skull. This sweating you have described is probably a direct manifestation of the sympathetic denervation that accompanies these types of insults. A perivascular injection in the jugular vein is probably the most common cause of this syndrome. Some of these horses may also come to have upper airway dysfunction due to paralysis of the left arytenoid cartilage in the upper airway, making the horse a "roarer" (a horse that exhibits some abnormal upper airway noise during exercise). My guess is, at this point, any other of the clinical signs of this syndrome that may have existed have resolved in your horse. Treatment-wise, its really limited to antiinflammatory treatments, treatment of any associated or underlying conditions that Ive described above, and ....time. The prognosis for your horse is excellent as long as the sweating is all that you encounter. That wont affect him detrimentally in any way. Keep an eye out for any of the other signs Ive mentioned, but Im guessing your're beyond them now. good luck and feel free to contact me again if you have any other questions or concerns.