Fipronil-amitraz-S-methoprene-triggered pemphigus foliaceus in 21 dogs: clinical, histological and immunological characteristics.

Abstract

BACKGROUND:

A recently launched topical ectoparasiticide containing fipronil, amitraz and S-methoprene has been associated with the development of an acantholytic pustular dermatitis similar to that of Promeris-triggered pemphigus foliaceus (PF).

HYPOTHESIS/OBJECTIVES:

Our objectives were to describe the clinical, histological and immunological features of this PF-like cutaneous adverse drug reaction.

ANIMALS:

Twenty-one dogs with a probable or definitive diagnosis of PF-like cutaneous adverse drug reaction were identified between May 2012 and February 2013.

MATERIAL AND METHODS:

Histology, direct and indirect immunofluorescence were employed to address the study objectives.

RESULTS:

Most dogs were middle-aged or older (median, 9 years) and of large size (median, 23 kg). In six dogs (29%), the PF-like lesions remained confined to the site of application, while 15 dogs (71%) exhibited lesions at distant sites. One or two applications of the ectoparasiticide were sufficient to trigger PF-like lesions in seven (33%) and six (29%) dogs, respectively. Systemic signs were reported in nine dogs (43%), all with lesions extending to sites distant from application areas. Tissue-bound antikeratinocyte IgG was detected in the lesional epidermis of eight of 19 (42%) cases by direct immunofluorescence, while serum antikeratinocyte IgG was detected in 10 of 14 (71%) cases by indirect immunofluorescence. Autoantibodies were found to target canine desmocollin-1 in 11 of 14 dogs (79%), but not canine desmoglein-1, by indirect immunofluorescence on transfected cells. These immunological findings were similar in cases with localized and distant disease.

CONCLUSIONS AND CLINICAL IMPORTANCE:

This new topical ectoparasiticide containing fipronil, amitraz and S-methoprene is capable of triggering the development of an acantholytic pustular dermatosis that is a clinical, histological and immunological close match for Promeris-triggered PF and naturally occurring autoimmune PF in dogs.

• Authors: Petra Bizikova, Keith E Linder, Thierry Olivry
• Journal: Veterinary dermatology (Vet Dermatol) Vol. 25 Issue 2 Pg. 103-11, e29-30 (Apr 2014) ISSN: 1365-3164 [Electronic] England
• PMID: 24666660 (Publication Type: Journal Article)
• Copyright: © 2014 ESVD and ACVD.

Chemical References

• Drug Combinations
• Insecticides
• Pyrazoles
• Toluidines
• amitraz
• Methoprene
• fipronil

Topics

• Animals
• Dog Diseases (chemically induced, immunology, pathology)
• Dogs
• Drug Combinations
• Female
• Insecticides (administration & dosage, adverse effects, therapeutic use)
• Male
• Methoprene (administration & dosage, adverse effects, therapeutic use)
• Pemphigus (chemically induced, immunology, pathology, veterinary)
• Pyrazoles (administration & dosage, adverse effects, therapeutic use)
• Toluidines (administration & dosage, adverse effects, therapeutic use)