Pastern dermatitis

Question 1

Pastern dermatitis is

Answer 1

an umbrella term for inflammatory cutaneous lesions
on the Lower extremities (palmar/ plantar
pastern) of horses.
* Mud fever, scratches, greasy heel, grapes etc.

Multifactorial syndrome
* Unspecific reaction to various irritants/ pathogens

Affects White skin more commonly as well as draft horses: look out for CPL (chronic progressive lymphedema).

Question 2

Clinical presentation of pastern dermatitis.

Answer 2

• Alopecia
• Dry scales, crusts
• Ulceration
• Thickened skin
• Erythema

The following May be present:
* Pain/ pruritus
* Lameness
* edema

CPL (chronic progressive lymphedema):
* Thickened skin folds, varying degrees of severity.

Question 3

Etiology and typical patient for pastern dermatitis.

Answer 3

Affects Draft breeds more. Hind limbs and Unpigmented skin more.

Genetics playing a role is Highly likely; but specific genes not known.

Dirt + moisture + opportunistic pathogens cause it.
Maybe Environmental allergens are involved.

Parasites too maybe:
* Chorioptes mites
* Strongyloides westeri larvae
* Trombiculid mites
* Microsporum spp.
* S. aureus, Dermatophiluscongolensis etc.
Think Causative or opportunistic.

Question 4

Diagnostics to use for pastern dermatitis.

Answer 4

• Skin scrape + swab culture
• Fungal culture
• Biopsy

Question 5

Tx of pastern dermatitis.

Answer 5

Soak and remove the scabs.

Shampoo the pasterns with antibacterial shampoo e.g. 4% chlorhexidine alternated with zinc shampoo (Zincoseb) Every other day.

Dry the skin and apply Antibacterial ointment e.g. Silver-sulfadiazine, sulfargin etc.

• Antifungal treatment: Imaverol washes
• Remove protein and other concentrates from feed.
• Add omega fish oil (aim for DHA 1.5 grams/day).
• Some cases get topical steroid cream.

Question 6

Describe Leukocytoclastic Vasculitis ini horses.

Answer 6

Aetiopathogenesis unclear, maybe:
– Photo-aggravation
– Wet conditions

Unpigmented skin more prone – lateral/medial
lesions with:
▪ Erythema
▪ Erosions, ulcerations
▪ Exudation and crusting
▪ Often with a circular, well circumscribed lesion.
▪ Leg edema and thickened skin

Biopsy the lesion but resolve secondary infections
first.

Tx with topical/Systemic Steroids and Control Secondary Infections. Use Sunlight Protection.

Question 7

Describe Chronic progressive lymphedema or CPL.

Answer 7

Is a progressive disease of the lymphatic system caused by a defect in lymphatic drainage & tissue
perfusion. Chronic inflammation + Secondary infections (e.g., mites, bacteria).

Cause not fully undertood but there’s a Genetic predisposition (likely heritable). Seen more in Draft breeds like:
* Shire
* Clydesdale
* Belgian Draft
* Irish Cob (Gipsy Vanner, Tinker)
* Fresian

Question 8

Clinical signs of Chronic progressive lymphedema or CPL.

Answer 8

• Swelling of the lower limbs (especially fetlocks)
• Thickened, folded skin with fibrosis
• Formation of skin nodules and plaques
• Hyperkeratosis (scaly skin)
• Recurrent infections, often with secondary bacterial or mite involvement.
• Lameness or reduced mobility over time

Question 9

Management of Chronic progressive lymphedema or CPL.

Answer 9

No effective treatment.

But to mange it:
* Clip the pastern feathers.
* Wash gently and dry carefully
* Topical Antibiotics for sec. bacterial infection
* Antiparsitic treatment against Chorioptes
* Daily exercise
* Manual lymph drainage
* Compression bandages
* Dry environment
* Regular trimming
* Forage based diet with Low sugar and starch <10-15%