We live in a time when young, otherwise healthy, active-duty individuals are undergoing traumatic amputations at an exceedingly high rate due to ongoing military engagements. According to US military casualty statistics through September 1, 2014, Operation Iraqi Freedom, Operation Enduring Freedom, and Operation New Dawn veterans have undergone a total of 1573 amputations.1 Walter Reed National Military Medical Center (WRNMMC) is one of several military facilities that has managed the care of these unique patients returning from the many ongoing conflicts around the globe. Multidisciplinary teams composed of surgeons, anesthesiologists, physical therapists, prosthetists, and others have joined forces to provide extraordinary emergency and recovery care for these patients. Even in the best hands, however, these traumatic amputee patients often experience long-term and lifelong sequelae of their injuries. As dermatologists at this facility (S.P. was at WRNMMC for 3 years before transferring to Madigan Army Medical Center), we are often asked to assist in the management of a subset of these sequelae: residual limb dermatoses. Residual limb dermatoses such as recurrent bacterial and fungal infections, cysts, abrasions, blistering, irritant and allergic dermatitis, pressure ulcers, acroangiodermatitis, stump edema, and many others have a high prevalence in our wounded warrior population and impact both amputee quality of life and utilization of medical resources. As many as 73% of amputees will experience a variety of residual limb dermatoses at some point in their life, with the highest prevalence in younger, more active patients.2,3 We have observed that many, if not most, of these cutaneous problems can be attributed to or are exacerbated by hyperhidrosis of the residual limb. Hyperhidrosis in this population of patients can be related to excessive sweat production, but more commonly, it is attributed to the lack of evaporation of normal perspiration.
Excess Sweat and the Prosthesis
To understand hyperhidrosis in amputee patients, it is important to understand the anatomy of the prosthesis. There are a variety of materials that are used to create prosthetic limbs. The most commonly used materials are a combination of plastic and carbon graphite/carbon fiber. The modern prosthetic limb uses a suspension system that attaches the prosthetic limb to the residual limb by creating a vacuum. There are several mechanisms to create this vacuum; however, they all depend on a liner that fits snugly over the residual limb. This liner-limb interface is responsible for protection, mitigation of sheering forces, and comfort, and it is the anchor for a good fit in the prosthesis. Unfortunately, this liner is the primary factor contributing to residual limb dermatologic problems. The liner usually is made of silicone or polyurethane and is designed to be water and sweat resistant; any excess water that finds its way into the liner-prosthetic interface will affect the seal of the device and cause slippage of the prosthesis.4 This water-resistant barrier is what induces the hyperhidrotic environment over the residual limb that is covered. These patients sweat with exertion, and because of the water-resistant liner, there is no mechanism for sweat evaporation. This leads to a localized environment of hyperhidrosis, increasing patients’ susceptibility to chronic skin conditions. In addition to the dermatologic pathology of the residual limb, there are notable functional concerns caused by excessive sweating. Increased moisture due to sweating not only leads to pathologic dermatoses but also to impaired fit and loss of suction by leaking into the prosthetic-limb interface, which in turn can lead to decreased stamina in the prosthesis, falls, and in severe cases even prosthetic abandonment.5