Drug Hypersensitivity Reactions Targeting the Skin in Dogs and Cats

Abstract

Adverse drug reactions (ADRs) can be dose dependent or idiosyncratic. Most idiosyncratic reactions are believed to be immune-mediated; such drug hypersensitivities and allergies are unpredictable. Cutaneous reactions are the most common presentation of drug allergies. In veterinary medicine it can be difficult to assess the true prevalence of adverse drug reactions, although reports available suggest that they occur quite commonly. There are multiple theories that attempt to explain how drug allergies occur, because the pathogenesis is not yet well understood. These include the (pro)-hapten hypothesis, the Danger Theory, the pi concept, and the viral reactivation theory. Cutaneous drug allergies in veterinary medicine can have a variety of clinical manifestations, ranging from pruritus to often fatal toxic epidermal necrolysis. Diagnosis can be challenging, as the reactions are highly pleomorphic and may be mistaken for other dermatologic diseases. One must rely heavily on history and physical examination to rule out other possibilities. Dechallenge of the drug, histopathology, and other diagnostic tests can help to confirm the diagnosis. New diagnostic tools are beginning to be used, such as antibody or cellular testing, and may be used more in the future. There is much yet to learn about drug allergies, which makes future research vitally important. Treatment of drug allergies involves supportive care, and additional treatments, such as immunosuppressive medications, depend on the manifestation of the disease. Of utmost importance is to avoid the use of the incriminating drug in future treatment of the patient, as subsequent reactions can be worse, and ultimately can prove fatal.

Clinical and Microscopic Characteristics of Canine Toxic Epidermal Necrolysis

“…12 To complicate this issue further, current canine dermatology review publications and textbooks continue to define TEN as having full-thickness devitalization of the epidermis with minimal dermal or epidermal inflammation. 10,16,28 Unfortunately, histopathologic descriptions of well-defined canine TEN cases are lacking in the literature. Drugs are thought to induce most cases of SJS/TEN, but infectious triggers dominate in EM, which implicates drug withdrawal as a crucial requirement for therapy and prognosis of SJS/TEN.…”

Therapeutic Potential of Gnidia Capitata L. F.: Investigations on Its Antityrosinase, Antibacterial, Antioxidant and Anticancer Activities

“…There are three distinctive layers of the skin which include the epidermis, dermis and hypodermis (subcutaneous) which have unique functions of protection and in maintaining homeostasis (Tabassum and Hamdani, 2014). A number of factors including hypersensitivity reactions may trigger skin and subcutaneous tissue disorders (Voie et al, 2012). Some individuals suffer several dermatological conditions such as skin dryness, itching, redness, scaly patches and lichenified thick plaques with excoriation (Tay et al, 2002;Worm, 2002).…”

Drug Reaction Caused by Clavulanate Amoxicillin in Dogs: Report of two CasesDrug Reaction Caused by Clavulanate Amoxicillin in Dogs: Report of two Cases

“…The use of antibiotics can lead to adverse reactions concomitant or subsequent to treatment, alteration known as pharmacodermia. In human patients, is a high incidence disease, which are affected in about 10-20% of patients treated with antibiotics, being considered the fifth major cause of mortality [4,5]. In veterinary medicine it is suggested that the casuistry may be underestimated, due to similarity with several skin diseases [1].…”

“…Cutaneous manifestations are characterized by vesiculobullous eruptions, erythema multiforme, toxic epidermal necrolysis, bullous pemphigoid and others [1]. The etiopathogenesis of pharmacodermia can be classified as dosedependent, in which reactions are associated with drug dosage, or dose-independent, when it relates to individual immune response of the animal [4,5]. The cause-dependent reaction is the most frequent and may have iatrogenic character.…”

“…The cause-dependent reaction is the most frequent and may have iatrogenic character. Their clinical correspond to adverse drug effects, being susceptible to any individual [5]. Idiosyncrasy correlates only to genetic predisposition, being uncommon and unpredictable, their exact mechanisms have not been completely understood yet.…”