Scratches, an itch that doesn't easily go away
Scratches, greasy heel, mud fever, dew poisoning... by any of those names it is equine pastern dermatitis and the nemesis of a western Washington winter. Not everyone has the luxury of a nice dry stable let alone somewhere to roam that isn't knee deep in February mud, so what do we do about dermatitis?
This malady so common to our region this time of year is inflammation and infection of the pastern and heel area of the horse. It is often painful and resistant to treatment once established. A constantly wet environment which decreases the essential function of the skin as a barrier to pathogens may be the inciting cause or a complication once inflammation begins. Contact irritation from allergies or treated bedding, insect or photo sensitivity, parasites, trauma and autoimmune disorders may all be inciting factors. A precise etiologic diagnosis is often difficult to come by since there may be one or multiple underlying causes for the inflammatory reaction. What is most clear is that a wet, muddy environment contributes significantly to the disease.
Skin is the largest organ of the body and when intact it presents a remarkable barrier to disease. It's no surprise that the horses lower limbs are exposed to a “manure load” of potential pathogens; bacteria, fungi, viruses, parasites etc. These organisms coexist happily ON the skin, it's when they sneak through the barrier and get INto the skin that problems begin. Signs of scratches include, red, swollen, sometimes itchy, scaly, crusty pasterns which may progress to oozing sores and granuloma formation. Much of the time the condition will improve with simple to prescribe but challenging to implement management practices. The primary goal is to provide a clean and dry environment, not so easy in our wet winters. Successful management in less than perfect conditions is still possible with a little effort and creativity. Trimming long hair around the pastern, physically cleaning the area and drying it as best you can and keeping it dry as much as possible are steps in the right direction. Several commercial topical applications can be useful to help improve the barrier function of inflamed skin or to soothe mild irritation. You can tell by the number of concoctions on the shelf that there is no single topical “cure all” that works consistently. It’s ok to try your favorite ointment or salve with the goal to decrease irritation and cracking of the skin but if the condition doesn’t improve or if it worsens it may be time for a more systemic approach to treatment. Your horse’s immune system may need an assist to clear the infection or break the cycle of inflammation. Scratches can become extremely difficult to resolve in its chronic form, or worse, it can lead to more widespread cellulitis which if left untreated can even be life threatening.
You’ve heard it before, “an ounce of prevention is worth a pound of cure” and it definitely applies to this disease. There are many approaches for management and treatment of simple cases of scratches. If you have any tips and tricks that have worked for your horses to minimize this problem we'd all love to hear them.