Introduction

• Inflammation of the hair follicle caused by Staphylococcal bacteria.
• Cause:Staphylococcus aureus  Staphylococcus aureus    Staphylococcus spp  ,S. intermedius,S. hyicus.
• Signs: papules, pustules, crusts, scales, nodules and annular areas of alopecia over the saddle and tack areas.
• Diagnosis: history, examination, cytology, bacterial culture, histopathology.
• Treatment: topical antibacterial agents, systemic antibiotics.
• Prognosis: good.

Pathogenesis

Etiology

• Staphylococcus aureus  Staphylococcus aureus  is the most common, followed byS. intermedius, and rarelyS. hyicus.

Predisposing factors

• Hot and humid environment.
• Frequent riding/heavy work load.
• High insect/tick population.

• Poorly maintained/muddy paddocks or stalls.
• Ill-fitting tack   Saddlery: principles  .

• Poorly groomed horses.

Pathophysiology

• Bacterial infection of the hair follicle secondary to cutaneous trauma.
• Advanced lesions may   →   rupture of the hair follicle (furunculosis) with corresponding dermal inflammation.

• Damage to skin, eg insect bite, trauma   →    staphylococcal bacteria invades and infects the hair follicle    →   small papule forms and overlying hairs may become erect    →   a pustule may arise from the papule, rupture and form a crust or    →   papule enlarges and may develop a central ulcer with purulent discharge    →   hair follicle may eventually rupture resulting in free hair shafts in the dermis (furunculosis) and an inflammatory foreign body reaction.

Epidemiology

• Can be spread via fomites, eg shared tack.

Diagnosis

Treatment

Prevention

Outcomes