Page 1522 - Clinical Small Animal Internal Medicine

1460 Section 12 Skin and Ear Diseases

in that it shows a pseudoepitheliomatous follicular
VetBooks.ir hyperplasia and perifollicular mucinosis.

Therapy
Treatment of Eutrombicula or Neotrombicula usually
consists of 1–2 applications of topical parasiticidal agents
or dips. Otic products that have parasiticidal properties
can also be efficacious. Studied products include 0.25%
fipronil spray applied to the entire body monthly for 1–4
months. Another evaluated option is a permethrin‐
pyriproxyfen topical spray or spot‐on for dogs for 1–2
treatments. Systemic glucocorticoids may be indicated
to alleviate pruritus and antibiotics may be of benefit if
secondary superficial pyoderma is present.
Treatment of Walchia americana consists of the same par-
asiticidal products used for the treatment of Eutrombicula
Figure 165.15 Eutrombicula alfreddugesi larva. Source: Courtesy of and Neotrombicula. Treatment of Straelensia cynotis has
Dr Erica Toledo. been suggested with macrocyclic lactones or fipronil.

late summer and early autumn. This mite is found in the
follicular ostia. It causes papules and nodules typically Ticks
over the dorsum and head. Alopecia, scale, and erythema
have been noted. Pruritus appears to be dependent on Ixodid (hard) ticks and argasid (soft) ticks both can affect
the presence of secondary infections. cats and dogs. The ixodid ticks, which have a chitinous
shield, can serve as vectors of rickettsial, protozoal, and
viral diseases. They may also cause a hypersensitivity
Diagnosis
reaction from their bite, and can sometimes result in tick
Diagnosis can be made with visualization of the reddish paralysis. The types of ixodid ticks of importance will
colored mite attached to the skin. Definitive diagnosis not be elaborated on in this section.
can be made by placing the mites obtained by skin Argasid ticks do not have the chitinous shield, or
scraping on mineral oil and examining the sample scutum. Otobius megnini can inhabit the ear canal in
microscopically. dogs and cats. The larvae and nymphs of this tick can
Diagnosis of Walchia americana is generally made lead to otitis externa. They can cause a severe irritation.
with skin scrapes. Biopsy can be helpful as well. Treatment includes manual removal of the ticks. Oil‐
Unfortunately, skin scrapings are unrewarding with based ear treatments may smother the tick. Prevention is
Straelensia cynotis. The mite can be found within the key to help reinfestation. Many topical and oral parasiti-
hair follicle on biopsy. Also, the histopathology is unique cidal treatments offer tick prevention.

Further Reading

Becskei C, de Bock F, Illambas J, et al. Efficacy and safety of Bowden DG, Outerbridge CA, Kissel MB, Baron JN,
a novel oral isoxazoline, sarolaner (Simparica™), for the White SD. Canine demodicosis: a retrospective study
treatment of sarcoptic mange in dogs. Vet Parasitol of a veterinary hospital population in California,
2016; 222: 56–61. USA (2000–2016). Vet Dermatol 2018; 29(1):
Beugnet F, de Vos C, Liebenberg J, Halos L, Larsen D, 19–e10.
Fourie J. Efficacy of afoxolaner in a clinical field study in Duangkaew L, Hoffman H. Efficacy of oral fluralaner for
dogs naturally infested with Sarcoptes scabiei. Parasite the treatment of Demodex gatoi in two shelter cats.
2016; 23: 26. Vet Dermatol 2018; 29(3): 262.
Beugnet F, Halos L, Larsen D, de Vos C. Efficacy of oral
afoxolaner for the treatment of canine generalized
demodicosis. Parasite 2016; 23: 14.