The purpose of this study was to summarize the clinical findings in 40 dogs with systemic hypersensitivity reactions associated with the administration of potentiated sulfonamides. Dogs ranged from 6 months to 14 years of age, with a mean of 5.7 +/- 3.2 years. Spayed female dogs were overrepresented (24 of 40, or 60% of the dogs), as were Samoyeds (3 of 40; 8%) and Miniature Schnauzers (5 of 40; 13%). Mean dosages of potentiated sulfonamides were 47.0 +/- 14.9 mg/kg/d (range, 23.4-81.4 mg/kg/d). The time from the 1st administration of the drug to the onset of the clinical signs of hypersensitivity ranged from 5 to 36 days, with a mean of 12.1 +/- 5.9 days. There was no relationship between either the dosage or type of sulfonamide given and the time to the onset of the clinical signs. Fever was the most common clinical sign observed (55% of the dogs); thrombocytopenia was 2nd (54%), and hepatopathy (28%) was 3rd. Neutropenia, keratoconjunctivitis sicca (KCS), hemolytic anemia. arthropathy, uveitis, skin and mucocutaneous lesions, proteinuria, facial palsy, suspected meningitis, hypothyroidism, pancreatitis, facial edema, and pneumonitis were also observed in some patients. Of 39 dogs with adequate follow-up, 30 (77%) recovered, whereas 8 (21%) either died or were euthanized, and 1 recovered clinically but had persistent increases in alanine aminotransferase (ALT) activity. Dogs with hepatopathy generally had a poorer prognosis (46% recovery) than dogs without hepatopathy (89% recovery; P = .0035). Sixty-three percent of the dogs with thrombocytopenia recovered, compared to 90% of the dogs without thrombocytopenia (P = .042). Recovery was not associated with sex, age, breed, or type of sulfonamide administered.

The purpose of this study was to summarize the clinical findings in 40 dogs with systemic hypersensitivity reactions associated with the administration of potentiated sulfonamides. Dogs ranged from 6 months to 14 years of age, with a mean of 5.7 3.2 years. Spayed female dogs were overrepresented (24 of 40, or 60% of the dogs), as were Samoyeds (3 of 40; 8%) and Miniature Schnauzers (5 of 40; 13%). Mean dosages of potentiated sulfonamides were 47.0 14.9 mg/kg/d (range, 23.4-81.4 mg/kg/d). The time from the 1st administration of the drug to the onset of the clinical signs of hypersensitivity ranged from 5 to 36 days, with a mean of 12.1 5.9 days. There was no relationship between either the dosage or type of sulfonamide given and the time to the onset of the clinical signs. Fever was the most common clinical sign observed (55% of the dogs); thrombocytopenia was 2nd (54%), and hepatopathy (28%) was 3rd. Neutropenia, keratoconjunctivitis sicca (KCS), hemolytic anemia, arthropathy, uveitis, skin and mucocutaneous lesions, proteinuria, facial palsy, suspected meningitis, hypothyroidism, pancreatitis, facial edema, and pneumonitis were also observed in some patients. Of 39 dogs with adequate follow-up, 30 (77%) recovered, whereas 8 (21%) either died or were euthanized, and 1 recovered clinically but had persistent increases in alanine aminotransferase (ALT) activity. Dogs with hepatopathy generally had a poorer prognosis (46% recovery) than dogs without hepatopathy (89% recovery; P .0035). Sixty-three percent of the dogs with thrombocytopenia recovered, compared to 90% of the dogs without thrombocytopenia (P .042). Recovery was not associated with sex, age, breed, or type of sulfonamide administered. S ulfonamide antimicrobials such as sulfamethoxazole and sulfadiazine are used to treat otitis, cystitis, and opportunistic infections in humans 1 and otitis, pyoderma, urinary tract infections, prostatitis, and atypical bacterial infections in dogs. 2 The use of sulfonamides and their po-tentiated formulations (containing trimethoprim or orme-toprim) in humans and dogs is limited by the delayed onset of hypersensitivity reactions, characterized in both species by fever, skin eruptions, hepatotoxicity, and blood dyscra-sias, with keratoconjunctivitis sicca (KCS) and arthropathy also reported in dogs. 3 The pathogenesis of these hypersen-sitivity reactions is not completely understood but is thought to involve both metabolic and immunologic mechanisms. A number of clinical reports have described sulfonamide-associated hypersensitivity in dogs and have been reviewed 4,5 ; however, to our knowledge, the characteristics of this syndrome have not been evaluated in a large group of dogs with systemic signs. The purpose of this study was to summarize the clinical findings in 40 dogs with sulfon-amide-associated hypersensitivity, along with the related is-Dogs were included in the study if they developed clinical signs consistent with an adverse reaction to potentiated sulfonamides after 5 or more days of treatment with sulfametho...

Similar humoral markers are present in dogs and humans with sulphonamide HS, supporting the use of dogs as a naturally occurring model for this syndrome in humans. These data suggest the potential use of drug-serum adducts and anti-drug antibodies as markers for sulphonamide HS. Preliminary data indicate that anti-sulphonamide antibodies may be triggered by the SMX-nitroso metabolite, not by the parent drug, in dogs.

Basal cell carcinoma (BCC) is the most common type of skin cancer, with rising incidence rates primarily attributed to an aging population and ultraviolet radiation exposure. While the majority of BCCs are localized and respond to standard therapies, a very small minority of these tumors become locally destructive or metastasize. These advanced BCCs may not be amenable to localized treatment with surgery and/or radiation therapy. Most BCCs result from mutations in key receptors in the Hedgehog (HH) signaling pathway. As a result, identification of drugs that inhibit the receptor Smoothened (SMO) in the HH pathway has resulted in novel therapeutic approaches to treating patients with advanced BCC. These HH-pathway inhibiting medications have shown efficacy in clinical trials, and two medications, vismodegib and sonidegib, have received FDA approval. However, several limitations of these drugs have been identified, including treatment-limiting adverse events, drug resistance, and the formation of additional malignancies. This paper aims to summarize the clinical trials leading to the approval of SMO inhibitors, as well as reviewing potential mechanisms driving tumor resistance and the formation of cutaneous squamous cell carcinomas. Strategies to overcome some of these challenges, including the development of drugs that inhibit other downstream targets in the HH pathway, are the subject of ongoing clinical trials.

Posttransplantation lymphoproliferative disorder (PTLD) is a rare complication of solid organ or allogenic bone marrow transplantation. Cases localized to the skin are even rarer, with only around 100 cases recorded in the literature [2]. We present a case of 60 year-old-woman, a lung transplant recipient, who presented with an asymptomatic violaceous nodule on her left medial calf. Histopathology was consistent with PTLD of the B-cell subtype, EBV negative. This case is unique in that it was of the B cell subtype of cutaneous PTLD, which has been less commonly observed than the T cell subtype. In addition, the case was EBV negative, which is rare in B cell cutaneous PTLD. The patient was treated with rituximab 600 mg IV weekly for four weeks and cytomegalovirus immune globulin (Cytogam) 100 mg/kg once, with resolution of the nodule.