Discussion

There are a huge number of equine dermatoses that can, with variable frequency, be pruritic at some level (Knottenbelt 2009; Scott and Miller 2011). Many of these are relatively typical in their historical and clinical presentation, and rarely seen (by me, anyway!). I find it useful to attempt (pending the owner's powers of observation) to divide pruritic dermatoses into 2 basic categories: 1) those that are initially pruritic in the absence of visible palpable lesions those that already have visible/palpable lesions at the time pruritus is recognised. With the caveat that any disease can probably do anything it wants to, I also find it helpful to prioritise pruritic region(s) of the body initially affected.
The approach to these dermatoses begins with a thorough history and physical examination (Knottenbelt 2009; Scott and Miller 2011). Laboratory tests are selected (or not) based on a prioritised (which is geographically variable) differential diagnosis (Knottenbelt 2009; Scott and Miller 2011). Investigations may include skin scrapings, trichography, cytology, fungal culture, skin biopsy, allergy testing, therapeutic trials, or combinations of these (Knottenbelt 2009; Scott and Miller 2011). Because the majority of pruritic horses I see have allergy(ies), I use many antipruritic agents