This skin problem turned out to be an allergic reaction to something and the skin was back to normal after the vet administered an antihistamine injection
Many equine skin problems have not been fully elucidated (analyzed and explained) yet, but experienced veterinarians often will recognize a problem and confirm a tentative diagnosis, if possible, with an appropriate test.
Owners need to realize that many disorders of the equine skin have not been subjected to close clinical or scientific scrutiny, and although the clinical features are known and thus often recognizable, little is categorically established about the pathogenesis and therapy.
Most equine skin cases are treated first by owners or others and only after this “treatment” has been unsuccessful is a veterinarian consulted. So veterinarians rarely see a “primary case.” For that reason, a good and thorough history is not always easy as the owner of the horse or the owner of the farm might not be the person who knows about the patient. A further complication is that sometimes-misleading statements are given. For example, the owner might report that the problem is acute when in reality the acuteness was caused by over-strength application of medication for a milder chronic problem, or the owner might not be willing to admit to the use of irritational, or any, treatments. Acting this way makes it much more complicated for the veterinarian to make a good (tentative) diagnosis.
Small patches of skin where hair isn't growing should be monitored
After taking a thorough history, the veterinarian will not only look at the skin, he/she will look at the animal as a whole, as many serious skin conditions are secondary to other underlying problems. For example, incomprehensible itch might be related to a tumor (paraneoplastic syndrome), or lesions limited to the white skin to liver disease (photosensitivity). So, especially in more difficult cases, the veterinarian will not only examine the skin but will perform a full clinical examination, including a rectal palpation and appropriate laboratory tests.
The veterinarian has a whole range of diagnostic tests available for dermatological problems. The most commonly used are the microscopic examination of hairs and crusts for parasites and fungi, bacterial and fungal cultures, skin biopsy, hematology and blood biochemistry. However, in some cases, there is no useful test to make a diagnosis, and tests can only be used to rule out specific differential diagnoses. An example: A horse shows several grayish rounded lesions with alopecia (hair loss) and some scaling. If the owner tells the vet that these lesions are acute and have developed in a few days, dermatophytosis (ringworm) is the most likely diagnosis, and the vet will collect material for a fungal culture by cleaning the lesions and their surrounding carefully with alcohol, waiting for the area to dry, and “plucking” hairs on the edge of the lesions. The fungal culture can take one to three days, and depending on the circumstances on the farm, the veterinarian will advise treatment (like bathing the horse with a topical antifungal agent like natamycin or enilconazole and cleaning the surroundings) or tell the owner that the dermatophytosis tends to be self-limiting and that many cases resolve spontaneously. Veterinarian and owner can discuss the advantages and disadvantages of both approaches.
Could this be ringworm? consult your vet for his opinion
However, if the owner tells the veterinarian that the lesions have been here for months and do not respond to treatment, the tentative diagnosis will be sarcoid tumor. In this case, the veterinarian will take a skin biopsy to confirm the diagnosis and explain the different treatment regimes that can be chosen after confirmation of the diagnosis by the pathologist.
Experiences have taught us that the cheapest and best solution for skin problems is an early consultation of the veterinarian. Some “waiting to see whether nature will solve the problem” might be acceptable, but treatment should never be started before a veterinarian has seen the case and taken appropriate samples, if indicated.
Written by: Marianne Sloet, DVM, Ph.D.
Many thanks to American Association of Equine Practitioners for allowing us to reproduce this article
