Conventional Western medicine has yet to provide a suitable treatment regime or identify a cause of equine anhydrosis. Two chronic cases and two acute cases of this disorder were treated successfully using acupuncture.
By identifying a TCM diagnosis of Heat invasion leading to exhaustion of Lung Qi and Wei Qi and a resulting Spleen Qi deficiency it was possible to resolve the acute cases with one treatment and the chronic cases with four treatments. Injecting acupuncture points with Vitamin B12 and using dry needling technique both seemed effective in treating this disorder.
Equine Anhydrosis (anhidrosis) is the absence of sweating. This disorder is also called “puffs”, puff disease, “dry coat” or dry coat syndrome. This disease is seen in tropical climates and seriously interferes with performance. Affected animals show respiratory distress even at rest and absence of sweating when all others are sweating heavily; they are unable to race or perform. This disorder is akin to anhidrotic asthenia of man . The etiology is unclear and treatment regimes for chronic cases are poorly documented. This paper deals with four cases that have been satisfactorily treated with Traditional Chinese Medicine (TCM).
Western Examination Findings
Horses are usually presented for examination and assessment for a loss of performance or exercise intolerance. It is at initial examinations that the hidrosis reduction is noted from the history. Some of these animals do not exhibit the increased respiratory effort of the “puffs” seen in more acute cases. The owner invariably reports that areas under the saddle are not as wet from sweat as they normally are after work.
Knottenbelt and Pascoe report that this condition characteristically affects horses that are moved to hot climates from milder temperature regions but it may also develop spontaneously in native horses. The onset of the condition is not always associated with poor acclimatisation or the type of work, but in some cases merely by the onset of hot humid weather. A single episode of profuse sweating before the onset of anhydrosis is often reported in acclimatizing horses. This is then accompanied by a dramatic reduction in water intake and a loss of body condition. Nostril flaring, a high respiratory rate and a high body temperature is usually all that is seen. The skin of chronically affected horses is dry with a “moth eaten” appearance, excessive scaling and some pruritis .
Eastern Examination Findings
These cases present as either acute as in Case Study 3 (CS3) and Case Study 4 (CS4) or chronic as in Case Study 1 (CS1) and case Study 2 (CS2). In the acute cases the most striking sign was the loud, dry, rapid breathing which persists after work, the absence of sweating and the high body temperature. These signs indicate there has been an invasion of Heat which is affecting the Lung. The pulse was thin and fast but there was a paucity of reactive points found on palpation. Both these horses failed to consume adequate amounts of water and their food intake was depressed. The decreased appetite and the presence of obvious thirst with little desire to drink indicates a Damp Heat invading the Spleen which in turn will deplete Spleen Qi.
A similar picture was presented by the chronic cases however both these horses were debilitated and very poor eaters. In these cases not only has the Spleen Qi been depleted, there is a lack of Qi being derived from the food as well. The Lung function of descending and dispersing along with the overall lack of Qi has resulted in these animals becoming debilitated. The most significant sign was the moth eaten dry scaly skin over their back with areas of alopecia and their inability to sweat. These symptoms indicate the function of the Lung is failing to regulate the skin and hair. Their pulse was slow and weak. The tongues looked normal with no coating.
In all cases the horses had an appearance of resignation to moderate distress. This indicates that there is ongoing emotional stress or disturbance of the Shen. The invasion of Heat has affected the Heart which governs the Shen.
Case Study 1
This eleven-year-old thoroughbred gelding was sweating normally two years ago when used routinely for pony club and low-level dressage work. He stopped sweating abruptly and began to exhibit typical symptoms of anhydrosis. He was given skin injections of adrenaline by a veterinarian, which elicited a poor sweating response (see below, Diagnostics). Over the next two years he was stabled and fed 500 grams of Vitamin C a week. The coat condition was poor and roughened and there was considerable loss of condition to the extent of the ribs, pelvis and sacrum were visible. The condition could only be described as approaching debilitation although the gelding was offered a high quality diet, was well cared for and wormed regularly.
This animal was treated with chiropractic and acupuncture.† This horse was given three treatments, each a week to ten days apart. The initial treatment went no further then gentle motioning of the spine and some non force due to the poor condition and the “hang dog” look of the horse. The manipulative treatment was followed by acupuncture treatment. Aquapuncture, using two millilitre injections of Vitamin B12 into the selected acupuncture points was the treatment chosen. The acupuncture points on the lower limbs were injected with only one millilitre of B12. In these it was necessary to angle the needle under the skin rather than being perpendicular to the body. Twenty five gauge inch long needles were inserted to full depth and then the syringe and injection was added and injected. The needles were left in place until the procedure was complete. This time was fifteen to twenty minutes. The Vitamin C and any other remedies were withdrawn.
There was a positive response after the first treatment and the gelding was more alert at the next treatment. The owner reported an increased interest in food but maintained that this could be all due to the huge amount of B12 the animal had received.
The second treatment involved motion palpation and chiropractic adjustments to thoracic and lumbar vertebral segments. The major restrictions were L4/5 and L6/S1 in the lumbar spine and T3/4, T4/5 and T6/7 in the thoracic spine. This was followed by the same acupuncture treatment as before. There was a sound response to this treatment with the horse showing a small area of sweat in the prescapular area on the right side at the end of the treatment.
The third and fourth treatment involved a full chiropractic examination and adjustments followed by acupuncture. The coat had improved dramatically and the horse was beginning to pace about the day yard with an interest in the surroundings and a better appetite. The gelding had a short ride one week later. At the conclusion he was trotted about for ten minutes. He sweated freely over the neck and back. The animal was gradually returned to work and sweats freely, has a healthy appetite and shiny coat.
Case Study 2
This fourteen-year-old dressage gelding was presented for chiropractic treatment after being diagnosed as a puffer twelve months earlier. The ribs, pelvis and traverse process of lumbar vertebrae were clearly visible along with the majority of the spinous processes. The top line was rough and looked as if it had widespread rain scald down the length of the spine. The 16hh horse had an extremely poor appetite, never finishing even ¼ of a meal. There was little gait abnormality but the horse was in no condition to be ridden. There was no history of sweating for the last year. The respiratory rate would remain elevated for 24 hours if the animal was worked or even ridden a short distance. There had been no work now for six months. On the last occasion the horse was worked the owners reported that the respiratory rate remained elevated for 72 hours.
Initially this gelding had two chiropractic treatments two weeks apart at which a number of thoracic and lumbar adjustments were made. Two further treatments were given at three-week intervals. At the end of this time the animal was reported to be eating much more on a daily basis but this still did not amount to adequate daily intake if the animal was to be worked. Three more treatments were given at monthly intervals. By this time the horses skin and condition had improved to the extent that he had resumed light to moderate work. During exercise only minimal sweating occurred initially under the saddle and a little over the neck in front of the scapula. At this stage it was decided not to continue the manipulative chiropractic treatments but to use acupuncture as the sole modality and see if there was an improvement in sweating.
Due to the success of the first case it was decided to use Aquapuncture using two ml injections of Vitamin B12 . Four treatments were given three weeks apart. After the first treatment there was a vast improvement in appetite over the next seven to ten days. The second treatment augmented the gains of the first and after seven to eight weeks resulted in the animal eating normally. With food intake restored the work load was increased. After the fourth treatment the gelding was back doing arena work and was sweating to the extent that it had to be hosed down after work.
Case Study 3
This was a 16hh thoroughbred galloper that was stabled at the race track in Springsure, a Central Western Queensland town. The climate in the area is comprises dry winters and hot summers. Humidity is worse in summer in the late afternoons when summer storms are common. This case was seen in June which is mid winter and very dry.
This horse had moved from the Gold Coast three months earlier and had only two starts against easier company. He was placed in the first start in a race that the trainer described as one he should have easily won. The horse came last in the second start. The trainer noticed that he did not sweat much after track work. After the second start, three weeks earlier the animal did not seem to sweat at all. As track work was done at daylight when the temperature was as low as minus five degrees the gelding was kept in work and showed no or very few signs of “puffs” or respiratory distress. On the other hand the quality of his work had deteriorated to the extent that he was now the slowest horse of the twenty two in work at the centre and there was conjecture that his efforts at track work warranted a long recovery. The coat looked reasonable and he was still eating but sometimes left up to half of the feed in his bin. Water was reticulated to each stall so it was difficult to assess his water intake.
There was only a one off opportunity to treat this horse and it was agreed to try the acupuncture method used earlier. No chiropractic assessment or techniques were used in this case. The animal was treated in his stall by injecting two ml of Vitamin B12 into the selected acupuncture points. He started sweating a little three days after the treatment and was back in full work and sweating freely four weeks later. His appetite and enthusiasm returned and he won at Mackay two months later.
Case Study 4
This bay four year old thoroughbred mare moved from New South Wales to Rockhampton and had three unsuccessful starts. There was no history of anhydrosis prior to her arrival and it was thought that she would win easily against easier company. After the third start the mare sweated profusely after the race in which she had run a “hard” second in a field of eight. The race was run at two ten in the afternoon on the second Saturday in March. This was a hot humid day which is common in the area. She continued to sweat in the swabbing stall as well as in the wash down bay. She was hosed for some thirty minutes but continued to sweat. The respiratory rate remained elevated for some two and a half hours after the race. The sweating gradually decreased over this time frame. These episodes are sometimes referred to as hyperhydrosis. The Tuesday following the race the mare was taken for track work. After the work there was no sweating and the respiration rate remained elevated for one and a half hours.
The mare was seen and assessed the following Thursday. A diagnosis of acute anhydrosis was made. This mare was treated with dry needles Serin No5(0.25)X30mm. This involved using the reducing method on the upper body points and leaving the lower limb points in place after insertion. Only one treatment was carried out. The mare resumed light track work one week later and sweated to the extent that it was considered no further treatment was necessary.
In considering the etiology of anhydrosis most postulations involve either the degeneration of the glands producing sweat or reduction in B2 adrenoreceptor stimulation. The synaptic transmitter involved is epinephrine (adrenalin) It has been suggested that horses with acute anhydrosis have increased circulating levels of epinephrine although determining such increased levels do not constitute a diagnostic aid.
Pascoe  uses a skin test using serial dilutions of adrenaline to establish if horses are truly anhydrotic. The skin is injected intradermally with serial dilutions of adrenaline of 0.5ml of 1:103 , 1:104, 1:105, and 1:106. Normal horses sweat at all dilutions whereas anhydrotic horses have reduced sensitivity and prolonged response time. In Case Study 1 it was found that the horse failed to sweat at 1:103 and 1:104. Further dilutions were not carried out.
Low levels of chloride and other electrolytes have been suggested as playing a role in anhydrosis. Laboratory analysis for electrolytes and other parameters are disappointing and seldom assist diagnosis. In the chronic cases the owners were of the opinion that nearly all investigations and treatments had been exhausted and therefore opted for treatment with alternative modalities.
Western Medical Diagnosis
The diagnosis of anhydrosis is based primarily on recognition of the abnormalities that have been described. Pascoe diagnoses this disorder from a history of loss of performance, increased respiratory effort and a skin test with adrenaline. Anhidrotic horses have reduced sensitivity and prolonged response time; normal horses sweat at all dilution’s .
Eastern Medical Diagnosis
In TCM using the Eight Principles Theory the horse had a disease which was Yang, external, hot and excess or full. The Zang Fu pathology diagnosis given for the anhydrotic horses was one of:
- External Summer Heat Invasion
- Lung Qi deficiency
- Spleen Qi deficiency and
- Yin deficiency
In each of these cases there has been an invasion of an external pathogenic factor Heat.
The most susceptible of the internal organs to external pathogens is the Lung. Heat is very Yang and has caused a Yin deficiency. In TCM the Lungs receive fluids from the Spleen and spreads them over the skin imparting healthy coat and normal opening and closing of the pores and normal sweating. The invasion of heat has damaged the primary Lung function of controlling Qi and respiration. In these anhydrotic horses the Lung is failing to spread the fluids from the Spleen to the extent that the horse can not sweat at all. Further the Qi has become seriously depleted and in particular the Defensive or Wei Qi. This is very apparent in the first two cases in which the animals were wasted or debilitated. In these chronic cases the weak Lung Qi has also affected the Spleen from which it derives part of its Qi. This has resulted in Spleen Qi deficiency.
This is evident from the history of each of the four cases. The acute cases CS3 and CS4 had suffered from overexertion with the latter having an episode of hyperhydration. The horse CS3 seemed to have the condition come on more slowly. The chronic cases, CS1 and CS2, also stopped sweating abruptly and the condition worsened with any exertion or work. These chronic cases both had a moth eaten rough scaly skin over the dorsum with some areas of alopecia suggesting that the Lung function over controlling the skin is impaired. The decreased appetite, muscle weakness and general fatigue is suggestive of Spleen Qi deficiency. The horse in CS3 showed these signs of fatigue and weakness in his training. Finally the chronic Lung Qi deficiency could lead to Deficient Lung Yin.
Treatment Principles & Results
From a Western medical approach in acute cases treatment is aimed at
- cooling the body (air-conditioned rooms and extended wash-downs)
- encouraging water intake with electrolytes
- lower calorie diet (restrict grain intake) and
- changes in the training regime.
In chronic cases the success of Western medicine has been limited and is based on the suspected cause. Treatment includes the above however many of these horses are eventually spelled or retired.
From an Eastern medical approach treatment is aimed at
- expelling Summer Heat
- restoring and regulating Sweating
- tonifying Lung Qi and Yin
- tonifying Spleen Qi
- promoting the circulation of Wei Qi
- relieve distress and grief
Treatment is thus aimed at expelling the Heat, strengthening the Lung Qi and Yin and restoring the sweating. BL 40 is used to clear Summer Heat. LU 1, LU 11, LI 11, and BL 60 are also used to clear Heat. LU 7 is particularly useful in promoting the circulation of Wei Qi, opening the nose to aid respiration and opening the pores to promote sweating.
KI 7 also helps regulate sweating along with LI 4 which also helps regulate Wei Qi. GV 14 also treats sweating disorders and helps calm the spirit. LU 7 is also useful in treating the emotional disorders of grief, worry and sadness. LU 9 tonifies Lung Qi and Lung Yin as well as activating the Lung meridian. The Spleen is tonified by BL 20 and the Lung is tonified with BL 13. The Shu of Diaphragm, BL 17 is particularly useful for the skin dehydration and dryness, as well as tonifying the Spleen and the whole body and harmonizing the breathing after the prolonged rapid respiration.
In the two acute and two chronic cases treated with acupuncture a successful resolution of the condition was achieved.
Healing the condition is difficult because scientists have not yet identified the cause of the disease. Theories include abnormality of the sweat glands, exhaustion of the sweat glands, loss of water and electrolytes and diminished function of the thyroid gland. Recent research has failed to support the theories about the structural defects in the sweat glands or any problem with electrolytes.
Historically, treatments for the non-sweater have been based upon the various theories of the cause of the disorder. Treatments include supplementation with salt, potassium and electrolytes, feeding vitamin E-selenium or iodinated casein, injections of ACTH or the use of thyroxin. All of these treatments have met with limited success – perhaps because there is not just one reason that horses become non-sweaters. Sweating is one of the body’s system which serves to maintain normal body functions. It is likely that there are many ways to cause a breakdown in the system – most of which are stressed induced: too much heat, too much exercise related to the level of fitness, too little shade, too little water.
TCM provides a different approach to the problem of resolving anhydrosis. Further TCM provides an explanation of why a horse which has had an initial bout of excessive sweating goes on to become anhydrotic. The Lungs control Defensive or Wei Qi which flows under the skin. Consequently when Lung Qi is weakened Wei Qi will also be weakened. Maciocia quotes extensively from The Yellow Emperor’s Classic of Internal Medicine- Simple Questions which was first published around 100 BC. In this ancient text the pores are called “doors of Qi”. The Lungs are described as controlling the skin and manifest in the hair (Maciocia 1989 p. 86).
“The main function of Defensive Qi is to protect the body from attack of exterior pathogenic factors, such as Wind, Cold, Heat and Damp. In addition it warms, moistens and partially nourishes skin and muscles, it adjusts the opening and closing of the pores (and therefore regulates sweating) and it regulates body temperature (chiefly by regulating sweating)”
(Maciocia 1989 p.45)
The Lungs disperse body fluids to the skin and muscles. These fluids combine with Defensive Qi. If this Defensive or Wei Qi is weak it may fail to hold these fluids in and spontaneous daytime sweating may occur. When the animal is heated (after a race) and sweats, or has extended spontaneous daytime sweating, Defensive Qi is lost in the sweat. When this happens the skin becomes obstructed along with the circulating Defensive Qi which in turn impairs the dispersing function of the Lung.. The result is the horse is unable to sweat at all. At this stage the only inherent mechanism the horse has left to loose heat is to increase its respiration rate. Defensive Qi originates from Essence and Original Qi and is transformed from Kidney-Yang (Maciocia, 1989 p.45). Thus protracted anhydrosis can lead to Kidney-Yang deficiency as seen in the chronic cases.
This condition should be distinguished from Exterior Wind-Cold invasion. Exterior Wind-Cold invasion can also obstruct the circulation of Defensive Qi blocking the pores and impairing the dispersing function of the Lung. In these cases promoting sweating aids restoring the dispersing function of the Lung results in the expelling Wind-Cold.
In the Five Element Creation Cycle the Earth element feeds the Lungs, which along with the Large Intestine comprise the Metal element. The Metal element feeds the Water element of the Kidney. Thus the paucity of primary Qi resulting in these cases effects the digestion as well as the water intake. These horses did not drink the amount of water that they usually did and their appetites were depressed. In the Five Element Creation Cycle the Metal element controls the Wood and the Fire elements. Thus the damaged Lung can also affect the workings of the Liver or the Heart (Schwartz, 1996 p.209)[6 ].
This concept of the Heart being damaged is explained further by Schoen.
“If sudden and severe enough, pathogenic Heat can cause even greater damage by penetrating the Pericardium. The result is a disturbance of the Shen, causing collapse and loss of consciousness (heatstroke).”
(Schoen, 2001 p.281) .
In CS3 the gelding was trained in the cold of the early morning. Despite the fact that it was cold and the case was acute he seemed to be less affected and showed fewer signs of respiratory distress. It is worth bearing in mind that the Lung is most active at 3.00 AM to 7.00AM. The mare in CS4 ran hard at 2.10PM which is very near the time when the Lung is least active.
Finally, the season of the Lung is Autumn and the emotion is grief. Queensland is noted for its distinct lack of seasons compared to the southern States. These animals may have been arguably suffering grief having been removed from their environment and stable mates.
Anhidrosis is a complex disorder the etiology of which is poorly understood. This condition also known as “puffs” is common in tropical regions but relatively unknown in temperate climates. These cases would suggest that anhidrosis is not an isolated disorder but rather part of a systemic problem with the appetite and the skin of the animal adversely affected as well. Whereas Pascoe has found that the condition may be acute, resolving the condition can be both frustrating and prolonged. These four cases would suggest that there is encouraging anecdotal evidence that treatment using acupuncture can be valuable in treating equine anhydrosis.
† An equine veterinarian,
Tom Ahern carries out a form of equine manipulation with the animal
under a general anaesthetic. On his Web Site Ahern reports anecdotal
evidence of resolution of cases of anhydrosis after cervical
manipulation in Asia where due to the climate the condition is common
 Ahern T, Tom J Ahern Equine Researcher, in
- Blood DC, a.S.V., Balliere’s Comprehensive Veterinary Dictionary. 1997, London: Balliere Tindall.
- Knottenbelt, D.a.P., R,, A Colour Atlas of Diseases and Disorders of the Horse. 1994, Barcelona: Wolfe.
- Ahern T, Tom J Ahern Equine Researcher, in http://geocities.com/CapeCanaveral/Lab/4763/anhyd.html 2002.
- Pascoe, R., Differential Diagnosis of Diseases of Horses. The T G Hungerford Vade Mecum Series for Domestic Animals, ed. P.g. Foundation. Vol. Series B, No 19. 1994, Sydney: University of Sydney Post Graduate Foundation in Veterinary Science.
- Maciocia, G., The Foundations of Chinese Medicine. 1989, Edinburgh: Churchill Livingstone.
- Schwartz, C., Four Paws Five Directions. 1996, Berkeley: Celestial Arts Publishing.
- Schoen, A., Veterinary Acupuncture. 2001, St Louis: Mosby.