Canine dermatitis on contacting grass leaf: A case series

Abstract

Background: Pruritus is a common clinical sign in dogs for which owners seek veterinary attention. Its diagnosis and treatment are often a source of frustration for the owner and veterinarian. Contact dermatitis is rarely considered, even when lesions are located only on the skin. This report describes the immediate reaction to grass leaf material after skin exposure, with similarities to human protein contact dermatitis. Hypothesis/Objective: To describe the history, clinical findings, diagnostic methods, and characteristics of an undescribed canine pruritic dermatitis that is clinically distinct from canine atopic dermatitis and contact dermatitis. Animals: Eighteen pet dogs living in Australia were referred for unresolved pruritic dermatitis. Materials and Methods: Retrospective analysis of clinical records from patients with pruritic dermatitis after contacting grass leaves. Findings on skin testing, isolation, challenge, and description of skin lesions are described. Results: Dogs had an inflammatory and pruritic dermatitis affecting the ventral chest, anterior-medial thighs and distal limb, areas that had been in contact with grass, which dogs instinctively avoided. Erythema and erythematous macules and papules were characteristic in the affected skin, inducing coat loss, and thickened pigmented skin. Isolating the dogs from grass resolved their clinical signs and pruritus returned within hours of contact with causative grass. Conclusion and Clinical Importance:A literature review revealed that this canine dermatitis was similar to human protein contact dermatitis. The impact may be enormous for the treatment of dogs having this disease because the treatment path differs from the therapeutic options of common canine pruritic skin disorders, including the possibility of cure by avoidance.

Immunoglobulin E‐specific allergens against leaf in serum of dogs with clinical features of grass leaf allergy

“…These dogs also reacted within 20 min of contact with specific (and not all) grass material present in their environment with a crude scratch test (cST). The positive test at 20 min supports the hypothesis of an immediate allergic reaction to the grass leaf 14 . This study tests for IgE allergen‐specific to grass proteins in leaf and pollen in the serum of dogs diagnosed with grass dermatitis 14 …”

“…Isolation from suspected grass led to clinical resolution, and the challenge back on the grass caused the condition to flare again. 14 These dogs also reacted within 20 min of contact with specific (and not all) grass material present in their environment with a crude scratch test (cST). The positive test at 20 min supports the hypothesis of an immediate allergic reaction to the grass leaf.…”

“…The positive test at 20 min supports the hypothesis of an immediate allergic reaction to the grass leaf. 14 This study tests for IgE allergen-specific to grass proteins in leaf and pollen in the serum of dogs diagnosed with grass dermatitis. 14…”

“…14 This study tests for IgE allergen-specific to grass proteins in leaf and pollen in the serum of dogs diagnosed with grass dermatitis. 14…”

“…Affected dogs tended to avoid walking on particular lawn grass, especially when wet. Isolation from suspected grass led to clinical resolution, and the challenge back on the grass caused the condition to flare again 14 . These dogs also reacted within 20 min of contact with specific (and not all) grass material present in their environment with a crude scratch test (cST).…”