Equine Lumps and Bumps 🐴
Name Description Clinical signs Diagnosis Treatment
Infectious or Inflammatory
Viral Papillomatosis Equine DNA papilloma virus [EcpV Multiple single or coalescent pink or Typical appearance +- Self-limiting disease → 3-4m
1] grey papules biopsy
(aka. Warts, grass warts, Cryotherapy, surgical removal or topical
verrucae) Usually young horses (<3yo) ⇒ Lesions have a hyperkeratotic surface DDs include verrucous wart medications if owners want to treat
may also affect with frond-like projections sarcoids, squamous cell (cosmetic)
immunocompromised older horses carcinoma, horse pox, and
(PPID) Common on muzzle, lips, around eyes, molluscum contagiosum
paragenital regions and distal limbs ^^ make sure to not
Transmitted by direct + indirect misdiagnose
contact (fomites)
Infection requires damaged skin
Pinnal Acanthosis Atypical form of papilloma virus → Raised depigmented PLAQUE-like Unlikely to resolve spontaneously
not a fungus lesions on inside surface of one or both
(Aural plaques) ears Best to leave alone – attempt treatment
Older horses (>2yo) often result in head shy horse
Lesions are typically covered with a
Seasonal onset (summer) ⇒ likely whitish keratinous crust Can try Imiquimod 5% ⇒ may cause severe
transmitted by flies inflammatory reactions
Eosinophilic Granuloma Frequent cause of nodular skin Single or multiple well circumscribed, Clinical signs +- biopsy Surgical removal or intralesional
disease in horses firm, non painful, non-pruritic nodules triamcinolone
(equine collagenolytic → approx. 3-5 cm in diameter
granuloma) Cause unknown → likely
hypersensitivity reaction to insects Distributed along neck, back and dorsal
(Seasonal problems) trunk
Other theories - pressure points
from tack/ distribution under
saddle
1
, Neoplastic
Sarcoids Most common skin tumor of Occult sarcoid: Characteristic clinical Factors affecting choice of treatment
horses (2-8% of horses affected) - Hairless, grey, scaly, roughly signs +/- biopsy +/- PCR - Location of sarcoid
circular patches of mildly Type of sarcoid
Fibroplastic, locally aggressive, thickened skin Biopsy may induce - Previous treatments • Prognosis
non-malignant cutaneous tumor - Mistaken for rubs, burns, proliferation ⇒ must treat - Potential for complications
All equid species are susceptible alopecia areata or ringworm + don't do it if it's clearly a - Owner and patient compliance
Verrucose sarcoid sarcoid - Facilities
Can occur at any age (most 2-9y) - Grey, scaly or warty
appearance, often with occult If can remove with laser use laser if in an
Both genetic and viral components halo area that cannot - use ECG
→ virtually all sarcoids are - Slow growing - not aggressive Benign Neglect
infected with type 1+2 bovine - Trauma can result in - Small sarcoids-not growing
papilloma virus transformation to nodular - Requires close monitoring
fibroblastic - Risky → can rapidly progress
General Clinical Signs: Nodular Sarcoids especially with trauma
- Can occur anywhere but - Easy to identify as discrete, - Not a cost-effective approach
predilection sites are: firm nodules under skin - Treatment when smaller has
- Axilla, groin, - Commonly in axilla, inner reduced morbidity, cost and
ear, periocular, thigh and eyelid improves outcomes
sheath - Type A ⇒ NOT ATTACHED to Ligation
- Often seen where flies go skin - Elastrator rings
→ flies attracted to - A1 ⇒ not attached - Limited to Type A1 and B1 nodular
traumatised area to skin or deeper sarcoids or Type 1A fibroblastic
- Once a horse had one - tissues sarcoid with defined neck and no
more likely to get more - A2⇒ Attached to root
- Failed treatment/trauma deeper tissues but - Case selection critical but can be
can trigger more not skin very cost effective
aggressive behaviour - Type B ⇒ attached to skin Topical immunotherapy → Imiquimod 5%
- 6 clinically recognizable - B1⇒ Attached to [Aldara]
forms skin but not deeper - Suited to superficial ocular and
tissue flat verrucous sarcoids
- B2⇒ attached to - Immune-modifying, antiviral and
skin and deeper anti-tumour properties
tissues - (Serious - Tazarotene 0.1% [Zorac] applied
type of sarcoid) daily for 2w → reduce superficial
Fibroblastic Sarcoid keratinisation → imiquimod 5%
- Fleshly and aggressive in every other day for 12 weeks
appearance Blood Root Ointment
- Easily ulcerated - attract flies - NA plant extract
- Type 1 ⇒ narrow pedicle - Cytotoxic and immune-
2
Name Description Clinical signs Diagnosis Treatment
Infectious or Inflammatory
Viral Papillomatosis Equine DNA papilloma virus [EcpV Multiple single or coalescent pink or Typical appearance +- Self-limiting disease → 3-4m
1] grey papules biopsy
(aka. Warts, grass warts, Cryotherapy, surgical removal or topical
verrucae) Usually young horses (<3yo) ⇒ Lesions have a hyperkeratotic surface DDs include verrucous wart medications if owners want to treat
may also affect with frond-like projections sarcoids, squamous cell (cosmetic)
immunocompromised older horses carcinoma, horse pox, and
(PPID) Common on muzzle, lips, around eyes, molluscum contagiosum
paragenital regions and distal limbs ^^ make sure to not
Transmitted by direct + indirect misdiagnose
contact (fomites)
Infection requires damaged skin
Pinnal Acanthosis Atypical form of papilloma virus → Raised depigmented PLAQUE-like Unlikely to resolve spontaneously
not a fungus lesions on inside surface of one or both
(Aural plaques) ears Best to leave alone – attempt treatment
Older horses (>2yo) often result in head shy horse
Lesions are typically covered with a
Seasonal onset (summer) ⇒ likely whitish keratinous crust Can try Imiquimod 5% ⇒ may cause severe
transmitted by flies inflammatory reactions
Eosinophilic Granuloma Frequent cause of nodular skin Single or multiple well circumscribed, Clinical signs +- biopsy Surgical removal or intralesional
disease in horses firm, non painful, non-pruritic nodules triamcinolone
(equine collagenolytic → approx. 3-5 cm in diameter
granuloma) Cause unknown → likely
hypersensitivity reaction to insects Distributed along neck, back and dorsal
(Seasonal problems) trunk
Other theories - pressure points
from tack/ distribution under
saddle
1
, Neoplastic
Sarcoids Most common skin tumor of Occult sarcoid: Characteristic clinical Factors affecting choice of treatment
horses (2-8% of horses affected) - Hairless, grey, scaly, roughly signs +/- biopsy +/- PCR - Location of sarcoid
circular patches of mildly Type of sarcoid
Fibroplastic, locally aggressive, thickened skin Biopsy may induce - Previous treatments • Prognosis
non-malignant cutaneous tumor - Mistaken for rubs, burns, proliferation ⇒ must treat - Potential for complications
All equid species are susceptible alopecia areata or ringworm + don't do it if it's clearly a - Owner and patient compliance
Verrucose sarcoid sarcoid - Facilities
Can occur at any age (most 2-9y) - Grey, scaly or warty
appearance, often with occult If can remove with laser use laser if in an
Both genetic and viral components halo area that cannot - use ECG
→ virtually all sarcoids are - Slow growing - not aggressive Benign Neglect
infected with type 1+2 bovine - Trauma can result in - Small sarcoids-not growing
papilloma virus transformation to nodular - Requires close monitoring
fibroblastic - Risky → can rapidly progress
General Clinical Signs: Nodular Sarcoids especially with trauma
- Can occur anywhere but - Easy to identify as discrete, - Not a cost-effective approach
predilection sites are: firm nodules under skin - Treatment when smaller has
- Axilla, groin, - Commonly in axilla, inner reduced morbidity, cost and
ear, periocular, thigh and eyelid improves outcomes
sheath - Type A ⇒ NOT ATTACHED to Ligation
- Often seen where flies go skin - Elastrator rings
→ flies attracted to - A1 ⇒ not attached - Limited to Type A1 and B1 nodular
traumatised area to skin or deeper sarcoids or Type 1A fibroblastic
- Once a horse had one - tissues sarcoid with defined neck and no
more likely to get more - A2⇒ Attached to root
- Failed treatment/trauma deeper tissues but - Case selection critical but can be
can trigger more not skin very cost effective
aggressive behaviour - Type B ⇒ attached to skin Topical immunotherapy → Imiquimod 5%
- 6 clinically recognizable - B1⇒ Attached to [Aldara]
forms skin but not deeper - Suited to superficial ocular and
tissue flat verrucous sarcoids
- B2⇒ attached to - Immune-modifying, antiviral and
skin and deeper anti-tumour properties
tissues - (Serious - Tazarotene 0.1% [Zorac] applied
type of sarcoid) daily for 2w → reduce superficial
Fibroblastic Sarcoid keratinisation → imiquimod 5%
- Fleshly and aggressive in every other day for 12 weeks
appearance Blood Root Ointment
- Easily ulcerated - attract flies - NA plant extract
- Type 1 ⇒ narrow pedicle - Cytotoxic and immune-
2
