b'CUT THE LEG CRUDTreatment Peters-Kennedy recom- Prevention Avoid sharing grooming mends lime sulfur as a topical dip ortools and other training aids unless you wash. Its a concentrate that must becan disinfect them. Peters-Kennedy says diluted, then applied to hair and skinthe organism can live for 18 months un-(and left to dry) once a week for aboutder favorable (warm, moist) conditions.four weeks. It smells like rotten eggs andTreatment Peters-Kennedy says mild will turn gray horses yellow, so its notinfections often resolve on their own, but cosmetically pleasing, she says, but itsshe recommends treating to prevent the a very effective antiparasitic, antibacte- disease from spreading. Fadok favors rial (fighting the bacterial infections thattopical antifungals containing azoles: commonly accompany Chorioptes), andmiconazole or ketoconazole shampoo. antipruritic treatment. Peters-Kennedy opts for a leave-on rinse of lime sulfur, as opposed to a shampoo, PHOTOS COURTESY DR. VALERIE FADOKRain Rot (aka Rain Scald,because it has more residual activity and Dermatophilosis) does not macerate or break hairs likeCauses Chronic warmth and dampnessshampooing can, causing the horse to that macerates (softens) the skin, leavingspread contaminated material.it vulnerable to entry by D. congolen-sis bacteria, especially in horses withSarcoidsnutritional imbalances and/or followingCauses Peters-Kennedy says these microtrauma to the skin such as scrapesDermatophilosis typically manifests as crustednonmalignant tumors usually occur when and insect bites. and ulcerated lesions. the bovine papillomavirus is present along Signs Crusted-over ulcerated spotswith skin trauma, and affected horses of skin covered by raised spots of haircontagious and often associated withseem to be fairly young (under 6 years).that can form on the shoulders, barrel,shared equipment such as boots andSigns Sarcoids can be occult (very hindquarters, lower legs, and/or faces ofgrooming tools. Fadok says some fungussubtle, often appearing as a circular patch horses that regularly stand in wet grassspecies (Microsporum gypseum) mightof hair loss that resembles ringworm), or mud. Peeling off the crusts results inalso exist in soil, particularly in the Southverrucous (warty), nodular and fibroblas-severe pain. where sandy pastures are common. Abra- tic (large and ulcerated, resembling proud Prevention Fadok says rain rot is conta- sions from the sand can make way for M.flesh, but not necessarily associated with gious, and many horses are permanentlygypseum invasion. Young horses, such asa wound), or malevolent (cancerlike). colonized with the bacteria, which live infoals and yearlings, are more commonlyThey most often develop on the head, a dormant form on the skin until acti- affected, as are horses under stress orbelly, groin, and legs and can be invasive vated by a combination of dampness andwith concurrent illness. and recurring. microtrauma to the skin. Keep your horseSigns Rounded, crusted patches ofPrevention Veterinarians believe the stalled until grass dries out later in thehair loss (hence the word ring). It canvirus might be transmitted by fly bites, day, and control insects with a permethrinsometimes appear as pastern dermatitisso be attentive to fly control, says Fadok. wipe or spray product to prevent bites. but can show up anywhere on the horsesAlso, tumors usually form where skin Treatment Fadok says antisepticbody. Veterinarians diagnose ringwormtrauma has occurred, so try to prevent shampoos containing chlorhexidine usu- by examining a stained sample of thewounds and abrasions. The tumor seems ally work. Peters-Kennedy prefers limecrust under a microscope. to be associated with horses that have a sulfur, whose antimicrobial propertiesparticular major histocompatibility com-usually knock the bacteria down. Ourplex (immune system) gene.sources agree that if topical treatmentsTreatment Sarcoids are difficult to fail, v eterinarian-prescribed systemic oralremove because its hard to get clean mar-antibiotics such as penicillin or trime- gins, but they dont metastasize (spread thoprim-potentiated sulfonamides (TPSs,or migrate to internal organs) so arent oral antibiotics) are the go-to medicationsusually fatal. Fadok recommends leav-for equine skin infections. ing occult sarcoids alone. Although they dont improve, they might not get worse. Ringworm But, they can progress to the fibroblastic Causes Dermatophyte fungus (one ofform. Theres no set-in-stone course of three mold genera: Trichophyton [Tricho- treatment, so consult your veterinarian phyton equinum], Microsporum, andto determine whats best for your horse. Epidermophyton) grows on skin, hair, andPeters-Kennedy says possibilities include other body surfaces and usually invadessurgically debulking the tumor in addi-the hair shafts, causing them to weakenThe fungal species M. gypseum tion to chemotherapy, such as cisplatincan invade and break off, leading to hair loss. Itslower leg abrasions, causing ringworm. injections.14April 2020The Horse|TheHorse.com'