VETERINARY NURSING EDUCATION SKIN VERSUS PEMPHIGUS FOLIACEUS AND THE AUTOIMMUNE GANG Lara Luke, BS, RVT, Dermatology, Purdue Veterinary Teaching Hospital This program was reviewed and approved by the AAVSB Learning Objective: After reading this article, the participant will be able to dis- RACE program for 1 hour of continuing education in jurisdictions which recognize AAVSB RACE approval. cuss and compare autoimmune diseases that have dermatological afects, includ- Please contact the AAVSB RACE program if you have any ing Pemphigus Foliaceus (PF), Pemphigus Erythematosus (PE), Discoid Lupus comments/concerns regarding this program’s validity or relevancy to the veterinary profession. Erythematosus (DLE), Systemic Lupus Erythematosus (SLE). In addition, the reader will become familiar with diagnostic and treatment techniques. FUNCTION OF THE SKIN Te skin is the largest organ of the body. Along with sensory function, it provides a barrier between the inside and outside world. Te epidermis is composed of the following fve layers: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum. Te stratum lucidum is found only on the nasal planum and footpads. When the cells of the epidermis are disrupted by systemic disease, the barrier is also disrupted. Clinical signs of skin disease will bring the patient into the veterinarian’s ofce for diagnosis. 32 THE NAVTA JOURNAL | NAVTA.NET VETERINARY NURSING EDUCATION THE PEMPHIGUS COMPLEX article.3 Histologically it shares characteris- Pemphigus Foliaceus tics of both PF and DLE.1 This classifcation PF is an immune mediated pustular disor- is still considered controversial and PE may der included in a group of diseases known just be a localized variant of PF.1 as the pemphigus complex. It is one of fve recognized types in which the body Deeper Forms of the Pemphigus produces antibodies that target the proteins Complex binding the cells of the epidermis.1 It is The deeper forms of the pemphigus considered the number one autoimmune complex exhibit more serious signs. PV disease in dogs and cats, but has also been includes oral cavity and mucosal lesions. reported in humans, horses, and goats. Fever and anorexia often accompany der- matological signs. PVeg also includes oral Desmosomes are the proteins that bind lesions, but wart-like lesions and plaques keratinocytes (epidermal cells) to each can also be present. PPP is a deep form Figure 1 other. They are the target proteins in the of pemphigus associated with neopla- A 7-year-old M/N Cocker Spaniel with PF. pemphigus complex, which includes the sia, especially thymic lymphoma and superfcial diseases PF and pemphigus splenic sarcoma. There have only been erythematosus (PE), as well as the deeper two cases of canine PPP reported in the Ultraviolet light has been shown to trigger pemphigus diseases, pemphigus vulgaris literature and both are deceased. Immu- PF outbreaks. In addition, in the canine (PV), pemphigus vegetans (PVeg), and nologic investigation of deceased patients patient, PF has been associated with such paraneoplastic pemphigus (PPP).3 When revealed that, as in the human form, the disorders as chronic skin disease, hypo- the desmosomes are untethered from presence of autoantibodies against mem- thyroidism, and systemic lupus erythema- each other, the breakdown of these con- bers of the plakin family were present.3 tosus (SLE).2 nections is called acantholysis.3 Plakins are proteins involved in cellular development and tissue integrity.4 The DIAGNOSING PEMPHIGUS FOLIACEUS Clinical signs of PF are evident as pus- prognosis in humans is poor. Obtaining a cytology tules.2 Because the pustules are fragile If PF is on the doctor’s list of differentials, and rupture easily, they may not be visible Causes Of Pemphigus Foliaceus diagnosing the condition involves cytology on physical examination. The patient There are several factors that may play a and histopathology. It is ideal to obtain may present only with epidermal collar- part in the development of PF, although the an impression smear from the material of ets from the ruptured pustules, as well as specifc predisposing trigger may not be an intact pustule. Using a sterile needle, crusts, scales, and erosions.5 In the canine found in most cases.3 The frst cause often rupture the pustule and press a glass patient, hyperkeratosis of the footpads considered is genetics. In canines, different slide against the exudate. Pustules are may also be evident (Fig 1). papers have listed several different breeds fragile and rupture easily, so they may be reported with the disease. However, it can rare on physical exam. If only one pus- In felines, clinical signs of PF are similar be agreed upon that the two breeds over- tule is found, save that for histopathology. to dogs with lesions covering the pinnae, represented are Akitas and Chow Chows. Material can be obtained from beneath any periocular regions, and footpads. Like the Cats and horses have not proven any crust or collarette. Heat fx the slide and dog, it can become generalized. In cats, breed predilection.2,5 Similarly, evidence of stain with Diff-Quick stain. the claw folds can also be involved. Horses breed predilection for PF is missing in the tend to have a more generalized pattern of author’s search of goat literature. The hallmark of PF is the presence of crusting, scaling, and alopecia. In caprine acantholytic keratinocytes (Fig 2). These patients, it is reported generalized over the Drugs have been implicated in trigger- are the immature cells of the epidermis body and the teats in females.1 ing PF. This happens when the drug whose desmosomes have been broken. induces acantholysis, activates proteolytic They have the appearance of rounded, Pemphigus Erythematosus enzymes that disrupt desmosomes leading darkly stained cells with prominent nuclei. The more benign form of the superfcial to acanthoylsis, or stimulates autoantibod- Other fndings can include nondegener- pemphigus complex, PE, generally limits ies against the desmosomes. Some drugs ated neutrophils and eosinophils.2 These clinical signs to the facial region, including that may be implicated are cephalexin, fndings are highly suggestive of PF, but depigmentation of the nose. Some consider amoxicillin, clavulanic acid, and cimetidine. dermatophytosis and pyoderma can also it to be a crossover between PF and dis- It is often diffcult to prove which drug in present with these cytological fndings. coid lupus erythematosus (DLE). Lupus ery- the patient’s history is at fault.2,3 This must be ruled out with a fungal thematosus will be discussed later in this culture because the immunosuppressive VETERINARY NURSING IN ACTION | JUN/JUL 2017 33 VETERINARY NURSING EDUCATION drugs used to treat PF are not recom- Treatment Options For mended for dermatophytosis.2 Pemphigus Foliaceus Histopathology For mild cases of PF, topical glucocorti- A biopsy should be submitted (ideally) to a coids (GCs) can be used to treat lesions. dermatohistopathologist for fnal diagno- Topical steroids can cause skin atrophy, sis of PF. A 6mm punch biopsy of at least so the patient must be monitored. For three different sites is recommended. If more severe cases, systemic GCs are the an intact pustule and/or crust is included, most common treatment. Because cats it is ideal. Equipment needed is a 6mm don’t metabolize prednisone as well as punch biopsy, a formalin jar, iris scissors dogs, they should be prescribed pred- or a scalpel, and forceps. A permanent nisolone. It is not recommended to use Figure 3 marker is used to circle the lesion of inter- injectable long acting GCs. The veterinarian A 6-year-old Australian Shepherd with DLE. est. Some of the instruments used will be needs to be able to adjust the dose based dependent on the personal preference on the patient’s response. Common side In one case, a Nigerian Dwarf goat kid of the doctor performing the procedure. effects observed include polyuria, polydip- developed PF at the age of two months. Amount of bleeding will depend on the sia, and polyphagia. Other, more serious Four weeks after treatment with GCs, site from which the biopsy is taken, so be side effects that can develop are iatrogenic she was still showing signs of fever, even prepared with gauze sponges. The site is Cushing’s disease, gastric ulcers, and dia- though her skin was improving. Gold closed with a non-absorbable or absorb- betes mellitus.2 salts were added to her therapy. The GCs able suture. If the dog is awake, a local were able to be decreased with time and block of approximately 1ml of 2% lido- GCs alone are often not enough to control eventually discontinued. After six months caine is used for analgesia. clinical signs of PF. Azathioprine can be of receiving gold salts, this treatment was used along with GCs or used alone once also able to be discontinued.6 This procedure is clean but not sterile, so it takes effect. It must be noted that this surgical gloves are not required; however, can take weeks, so the veterinarian may LUPUS ERYTHEMATOSUS exam gloves should be worn. Any hair can choose to keep the patient on GCs during Discoid lupus erythematosus be clipped with a pair of scissors, but care that time. Potential side effects of Azathi- A differential diagnosis for PF is Lupus Ery- should be taken not to disturb the crusts aprine can include bone marrow suppres- thematosus. Discoid Lupus Erythematosus or damage the skin. The site should not be sion, hepatotoxicosis, pancreatitis, and GI (DLE) is a fairly benign condition that may prepped as the crusts contain many of the signs, such as vomiting or diarrhea.2 It is be aggravated by ultraviolet light exposure. cells pathologists use to make a diagnosis. important to perform a CBC and chemistry This may be the second most common After the veterinarian has taken the samples, profle regularly to monitor organ function.