Greasy Heel

Also known as:

Grease Heel Pastern Folliculitis Pastern Dermatitis

Description

Greasy heel is not a single disease but refers to the clinical presentation of a group of inflammatory skin conditions of the distal limb of the horse. Several aetiologies have been suggested including immunodysregulation, contact dermatitis and genetic (breed) predisposition. Predisposing factors include constant wetting, non-pigmented skin and abrasions to the limb. Multiple bacteria are thought to have a role in the disease and include Dermatophilus, Staphylococcus, Fusiformis and Dermatophilus.

Signalment

Greasy heel has no sex predilection in the adult horse. Although all breeds are affected, draft horses such as Shires and Clydesdales are more prone to developing the condition. It has been hypothesised that these breeds are particularly affected due to underlying immune-mediated vasculitis.

Clinical signs

Skin lesions are seen most commonly in non-pigmented areas at the palmar or plantar aspect of the pastern. Hindlimbs are most commonly affected and lesions are often symmetrical. The dermatitis is initially characterised by erythema, alopecia, exudation, pruritus and crusting of the lower limb. Lameness may occasionally be a feature of the condition. In chronic cases, thickening of the skin occurs with hyperkeratosis and fissure formation.

Diagnosis

The list of differential diagnoses for this condition is lengthy and several important conditions should be ruled out. If lesions are restricted to non-pigmented skin only, liver enzymes and bile acids should be evaluated in order to rule out photosensitisation as a cause of disease. Skin scrapes should be performed in order to rule out parasites such as Chorioptes mites (especially in heavily-feathered horses).