Trichoscopic diagnosis of cutaneous Pelodera strongyloides infestation in a dog

Pelodera strongyloides infestation has rarely been reported in dogs. It is a saprophytic free-living nematode, found in moist decaying organic matter, whose L3 larval stages occasionally can invade the skin of dogs and humans. Larvae penetrate the follicular infundibula causing an erythematous and pruritic dermatitis. The disease is usually diagnosed by deep skin scraping or histopathology, with large numbers of parasites readily identified in hair follicles.

Pelodera strongyloides dermatitis was diagnosed in a six-year-old mixed breed dog presenting with alopecia, erythema and severe pruritus on the ventrum and limbs. The infestation was diagnosed by microscopic examination of plucked hair shafts and confirmed on microscopic examination of skin biopsies collected for histopathology. Only two of 10 deep skin scrapings gave positive findings. The nematode infestation was eradicated following two applications, 2 weeks apart, of a moxidectin/imidacloprid spot-on product.

Skin scrapings are considered the diagnostic test of choice for P. strongyloides infestations. In this case, parasites were identified by hair trichograms more readily than by skin scrapings.