Content continues after advertisement

Tick-Related Skin Lesions

Clinician's Brief (Capsule)

Infectious Disease

|July 2014

Sign in to Print/View PDF

Canine granulocytic anaplasmosis (CGA) is caused by Anaplasma phagocytophilum. This parasite is transmitted by several species of ixodid ticks in North America, Europe, and Asia. The clinical signs include fever, thrombocytopenia, lethargy, anorexia, arthropathy, and other nonspecific signs. Skin lesions have been reported in other species but not in dogs.

In this retrospective study, 52 skin biopsy specimens from 12 dogs seropositive for A phagocytophilum and responsive to doxycycline were compared with 2 specimens from 2 seronegative dogs and with 11 skin biopsy specimens from 10 dogs with unknown serologic status, compatible with tick-bite reactions. A phagocytophilum DNA was amplified in 4 of 12 seropositive dog samples. Skin lesions from the 12 dogs varied and included, but were not limited to, erythema, plaques, erosions, and crusts. Lesions were found on the head, ventral neck, ears, and ventral abdomen. Skin biopsy findings in all seropositive dogs included, but were not limited to, a perivascular-to-interstitial infiltrate of the superficial and deep dermis. A phagocytophilum was not amplified from seronegative and tick bite dogs. In 8 of the seropositive dogs, histologic findings included vasculopathy, fibrinoid necrosis of the vessel walls, and leuko-
cytoclastic changes.

Commentary

The most common tick-borne illnesses are borreliosis, canine anaplasmosis, Rocky Mountain spotted fever, ehrlichiosis, babesiosis, and canine hepatozoonosis. Lack of adequate tick control is the most important risk factor for dogs. The clinical signs of these diseases overlap, and definitive diagnosis depends on laboratory diagnostics. It is likely that skin biopsy specimens were obtained in these cases because the lesions developed in close association with the onset of systemic illness. Although the histologic review did not identify a causative agent, the key finding was presence of histologic changes compatible with vasculitis. In addition, it was likely an unexpected finding because the gross clinical descriptions were not typical of classic vasculitis. From a practical perspective, it is important to remember that vasculitis is not a definitive diagnosis, but rather a reaction pattern, often a sign of systemic illness. If found during skin biopsy, a thorough search for the cause is warranted.—Karen A. Moriello, DVM, DACVD

Source

Anaplasma phagocytophilum DNA isolated from lesional skin of seropositive dogs. Berzina I, Krudewig C, Silaghi C, et al. TICKS TICK BORNE DIS 5:329-335, 2014.

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Clinician's Brief may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.

Podcasts

Clinician's Brief:
The Podcast
Listen as host Alyssa Watson, DVM, talks with the authors of your favorite Clinician’s Brief articles. Dig deeper and explore the conversations behind the content here.
Clinician's Brief provides relevant diagnostic and treatment information for small animal practitioners. It has been ranked the #1 most essential publication by small animal veterinarians for 9 years.*

*2007-2017 PERQ and Essential Media Studies

© 2023 Educational Concepts, L.L.C. dba Brief Media ™ All Rights Reserved. Terms & Conditions | DMCA Copyright | Privacy Policy | Acceptable Use Policy