Horses are itchy this time of year. From biting flies and swarming gnats to allergies, some horses try to scratch themselves raw!
Equine skin diseases are a significant problem in many parts of the country. Because of the humidity, the southern United States sees many forms of skin disease continue through the winter, while the northern climates get a break from some conditions in the colder weather. Treatment can be frustrating from a conventional perspective as the drug selection is limited. If the commonly used drugs fail, there are not many other choices. Complementary medicine offers the practitioner many choices, and if one modality fails to help the horse, there are usually many options. Even then, some cases can be very refractory to treatment.
Allergic skin reactions
The most common skin cases that present to the veterinarian are allergic, pruritic horses in the summer time. Allergic reactions can be mild to severe ranging from itching without eruptions to raw, bloody eruptions.
Many factors can be involved, including pollens, foods, Culicoides mites, topical reactions to weeds, reactions to shampoos and detergents in saddle pads, dust, molds and more. Allergy testing can be done, using skin tests for inhalant allergens, blood tests for both inhalant and food allergens. However, with the equine, it is impossible to remove many airborne allergens from their environment. It is much easier to change the terrain (i.e. the horse’s immune system) than it is to change the environment.
A good history, with information about the onset of the symptoms can help determine the basic class of allergen (ex: tree pollens in the early spring, ragweed in late summer). With food allergens, it may be hard to determine without some form of allergy test.
Treatment conventionally is generally done with corticosteroids and sometimes antihistamines. If the skin has significant eruptions, antibiotics may be used to prevent secondary infections. Steroids do have some considerable risk and are not suitable for long-term use, year after year. They can cause or worsen gastric ulcers, they suppress the immune response so the horse is more susceptible to bacterial or viral infections. Many other side effects can occur.
The most severe complication with the use of steroids is in the horses with Insulin Resistance or Cushing’s. Though in research settings, laminitis is not often seen, in clinical practice laminitis post steroid treatment is seen. This author has observed a number of cases where even with a small dose, (as from a joint injection) life-threatening laminitis has occurred.
Complementary medicine offers many possible solutions to treating allergic skin disease. Simple cases may respond quickly to a single modality, but refractory or long-standing cases may require the treating veterinarian to have extensive training in homeopathy or herbal medicine.
Most allergic skin cases will benefit from high levels of Omega 3 fatty acids, in the form of flax, hemp or chia seeds, either as an oil or in the seed form. Omega 3 Fatty acids support and regulate the immune system. In humans, overweight people have been found to have reduced immune function, and the same is likely true to some extent with the horse. Most horses exhibiting pruritis from allergies will improve significantly with fatty acid supplementation. Flax and hemp oil can be supplemented at a rate of two to four ounces per day, or whole seeds fed at eight to twelve ounces per day. Naturally stabilized ground seeds can be used, but if not stabilized, will oxidize as soon as they are ground.
Both Chinese and Western herbal formulas can provide the tools to help heal these cases. In Western medicine, pruritis is usually considered a single condition, with many possible allergic triggers. In Chinese medicine there are many different Chinese Medical patterns seen with this one condition. In this overview article there is not room to discuss each pattern and formula, but maybe in a future article.
An example of a formula for treating itchy, raw, oozing skin would be the classical formula Long Dan Xie Gan Tang, a formula that clears the Chinese condition of Damp Heat. In the hot, humid summers of the East Coast and the South, this formula is effective.
Western herbal formulas often include soothing herbs such Buckwheat, Nettle, Chamomile, Garlic and Calendula. Western herbs are easy to feed horses, as they usually like the flavors and they are able to digest the herbs with minimal processing on the part of the manufacturer.
Most of the healing that needs to be done, is accomplished by internal means. However, some topical relief is often desired and useful. Strong black tea acts as an astringent and is easy to apply over a large portion of the skin for some relief. Herbal preparations of Calendula, Noni, Aloe Vera, plantain leaves (Plantago officinalis) all can help relieve the itch until the internal treatment restores the immune system.
Sarcoids are generally benign tumors that appear in the skin and may have a bovine papilloma virus origin. They are generally only locally invasive and often will not spread and cause a problem. However, due to location or excessive growth they need to be treated. Those that are in an area where tack can rub or are encroaching on the eyelids definitely need treatment. Some tumors are very aggressive locally though seldom metastasize.
Conventional treatment includes surgical removal or cryosurgery but both of these techniques often lead to reoccurrence. Sometimes the reoccurrence can be more aggressive than the original tumor.
BCG (bacillus of Calmette and Guerin) is frequently used by injection into the tumor. This treatment carries a certain amount of risk, particularly since the tumors that seem most responsive to it occur near the eye. Horses can react adversely to the protein in the injection causing a serious inflammatory reaction. It has been noted in England that tumors on the lower limbs injected with BCG can get significantly worse. One promising conventional treatment is the use of imiquimod (a topical drug used for human papillomavirus infections and skin tumors). (1)
Complementary treatments include homeopathic medicine, herbal supplements and topical applications of herbal preparations. Homeopathic medicines are usually prescribed according to the appearance of the tumor along with any other symptoms the horse has. Remedies such as Thuja, Causticum, and Sulphur are commonly prescribed, however there are many more, giving the homeopath many possible choices, if one is not working.
Topical applications called escharotics or Black Salves, made with the herb Bloodroot, have been used for many years. Tumor tissue is selectively destroyed by the salve, however it can leave a large wound that will heal slowly, but usually without incidence. Chinese herbal formulas can be used to help stimulate the immune system to remove large masses.
An extract of Mistletoe (Iscador P) has been shown to reduce or eliminate sarcoids in 41% of the cases treated. (2) This extract has been safely used for many years in Germany as a part of cancer treatment in humans. There are no side effects, but a small injection needs to be done into the lesion several times a week until it has healed.
Rain rot (dermatophilosis), scratches, greasy heel, mud rash and many other regional names are given to lesions on the back and lower legs, often seen in wet conditions and frequently seen in the colder climates and seasons.
Conventional treatment usually requires baths in an antimicrobial shampoo and picking the scabs that form off. This can be problematic in cold wet conditions as the horses do not dry well and may become chilled. It also can be very painful to keep picking scabs. More severe cases are usually treated with antibiotics, which also kill the beneficial bacteria in the gut.
Homeopathics offer a simple solution that does not require bathing. For lesions on the back, oral remedies such as Tellurium, Sepia, Thuja and occasionally Sulphur usually stops the infection in a week or so, then the scabs become dry and naturally fall off during grooming. For lesions on the legs, the more common remedies are Antimonium Crud, Graphites and Sulphur.
The dosing of homeopathic remedies for horses is about six to eight pellets of a 30 or 200 potency (strength), given once a day for three to seven days. In many cases, three days at a time is enough for the response to begin; then if there are still signs of tenderness at the lesions in two weeks, a second round of three days can be done.
Topically, salves can help lessen the soreness and promote healing of the tissue, but usually is not the primary factor in curing the condition.
Many other skin conditions can be treated with the use of complementary modalities. The practitioner should consider complementary medicine for these cases, especially the refractory ones.
1. University of Minnesota (http://www.cvm.umn.edu/cic/completedstudies/)
2. Treatment of clinically diagnosed equine sarcoid with a mistletoe extract (Viscum album austriacu. J Vet Intern Med. 2010 Nov-Dec;24(6):1483-9. doi: 10.1111/j.1939-1676.2010.0597.x. Epub 2010 Oct 12