Comparison of hair follicle histology between horses with pituitary pars intermedia dysfunction and excessive hair growth and normal aged horses

Innerå, Marie; Petersen, Annette; Desjardins, Danielle R.; Steficek, Barbara A.; Rosser, Edmund J.; Schott, Harold C.

doi:10.1111/j.1365-3164.2012.01080.x

Cited by 25 publications

(21 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The long hair coat in horses with advanced PPID has recently been determined to be due to the persistence of hair follicles in the anagen stage and is therefore more correctly termed “hypertrichosis”. 25 Follicles arrested in the anagen stage fail to shed, as occuring in PPID-affected horses and ponies. Hirsutism, the term commonly used to describe the hair coat changes in PPID-affected horses and ponies, has been borrowed from the medical field and refers to the excessive androgen-dependent growth of hair in women with Cushing’s disease.…”

Section: Diagnosticsmentioning

confidence: 99%

Equine pituitary pars intermedia dysfunction: current perspectives on diagnosis and management

Spelta¹

2015

VMRR

View full text Add to dashboard Cite

Equine pituitary pars intermedia dysfunction (PPID) is a neurodegenerative disease of the hypothalamus, resulting in the loss of dopaminergic inhibition of pars intermedia. An oxidative stress injury of unknown etiology has been suggested to initiate the neurodegeneration. While hypertrichosis (formerly known as hirsutism) is considered pathognomic for advanced disease, the antemortem diagnosis of subclinical and early disease has continued to prove difficult. Numerous tests have been used with varying sensitivities and specificities. The overnight dexamethasone suppression test, originally documented to have 100% sensitivity and specificity in horses with advanced disease, has proven to be less valuable in identifying early disease. Basal plasma adrenocorticotropin concentrations have improved sensitivity and specificity when sampled during the autumn months, and α-melanocyte-stimulating hormone, while not yet commercially available, shows promise as a sensitive and specific single sample test. Recent advances in our knowledge include the strong association between laminitis and hyperinsulinemia, both common clinical signs associated with PPID. The pathogenesis of hyperinsulinemia, laminitis, and their association with this disease is a focus of current research. The dopamine agonist pergolide mesylate is still the mainstay of medical management, with studies on oral bioavailability, pharmacokinetics, and long-term survival rates now published.

show abstract

Section: Diagnosticsmentioning

confidence: 99%

Equine pituitary pars intermedia dysfunction: current perspectives on diagnosis and management

Spelta¹

2015

VMRR

View full text Add to dashboard Cite

show abstract

“…One study found that telogen hairs represented 75% to 85% of the total number of hair follicles counted in equine normal skin from the neck and rump (Innera et al . ). However, comparison with these numbers is not possible as this ratio varies with species, individual, environmental and metabolic fluctuations.…”

Section: Discussionmentioning

confidence: 97%

“…In our case, it seems difficult to say if this number is increased as there are data on the physiologic ratio of catagen/telogen versus anagen hairs in donkeys. One study found that telogen hairs represented 75% to 85% of the total number of hair follicles counted in equine normal skin from the neck and rump (Innera et al 2012). However, comparison with these numbers is not possible as this ratio varies with species, individual, environmental and metabolic fluctuations.…”

Section: Discussionmentioning

confidence: 99%

Mutually‐induced traumatic alopecia responsive to husbandry modification in two cohabiting donkeys

Brément

Hermange

Degorce‐Rubiales³

et al. 2018

Equine Veterinary Education

View full text Add to dashboard Cite

Summary Cutaneous expression of behavioural processes remains unexplored in donkeys. This case report describes a case of traumatic alopecia in two donkeys secondary to mutual hair plucking behaviour. Two genetically unrelated, male castrated, 4‐year‐old Cotentin donkeys living together were presented for a 2‐year history of alopecic, mainly nummular, nonpruritic lesions developing on the back, loin and croup. The general physical examination and behavioural assessment were unremarkable. Trichoscopy, scrapings and cytology were performed. Superficial bacterial infection was diagnosed but a 2‐week course of antibacterial treatment showed no improvement. Histopathological examination showed features compatible with traumatic alopecia and consistent with several behavioural causes of alopecia resembling human trichotillomania or acute traction alopecia, canine traction alopecia, feline self‐induced alopecia and murine barbering. Separation of the donkeys led to complete long‐term remission. Clinical and histopathological findings in our case share lots of similar features with the different mechanical traumatic alopecic disorders mentioned above, making it impossible to simply classify the described affection. Whether alopecic lesions resulted from an exclusive behavioural process (either abnormal excessive mutual grooming or other social interactions) or were associated with underlying causes of pruritus is uncertain. Mechanical alopecia secondary to a behavioural process should therefore be suspected in cases of permanent patchy alopecic nummular lesions on donkeys living in groups.

show abstract

“…Older horses have increased susceptibility for overheating during exercise, due to age related alterations in physiological mechanisms important for thermoregulation (McKeever et al, 2010). Knowing that also hair coat quality (Brosnan and Paradis, 2003 a,b;Innerå, et al, 2013;McGowan et al, 2010) and the distribution of adipose tissue may change in elderly horses (McGowan, 2010), age is another individual factor to be considered when deciding how to best manage a horse in changing weather.…”

Section: Introductionmentioning

confidence: 99%

Effects of hair coat characteristics on radiant surface temperature in horses

Jørgensen

Mejdell

Bøe

2020

Journal of Thermal Biology

View full text Add to dashboard Cite

Horse owners may lack knowledge on natural thermoregulation mechanisms in horses. Horses are managed intensively; usually stabled at night and turned out during the day, some are clipped and many wear a blanket, practices which reduce the horse' ability to regulate the heat dissipation. The aim of this study was to investigate the relation between hair coat characteristics, body condition and infrared surface temperatures from different body parts of horses. Under standard conditions, body surface temperature of 21 adult horses were investigated using infrared thermography. From several readings on the same body part, a mean temperature was calculated for each body part per horse. Detailed information on horse breed, age, management and body condition was collected. Hair coat samples were also taken for analyses. A mixed statistical model was applied. Warmblood horse types (WB) had lower hair coat sample weights and shorter hair length than coldblood horse types (CB). The highest radiant surface temperatures were found at the chest 22.5 ± 0.9 °C and shoulders 20.4 ± 1.1 °C and WB horses had significantly higher surface temperatures than CB horses on the rump (P<0.05). Horses with a higher hair coat sample weight had a lower surface temperature (P<0.001) and hind hooves with iron shoes had a significant lower surface temperature than unshod hind hooves (P=0.03). In conclusion, individual assessment of radiant surface temperature using infrared thermography might be a promising tool to give horse owners objective management advice, based on the individual horse's actual needs at the time.

show abstract

Comparison of hair follicle histology between horses with pituitary pars intermedia dysfunction and excessive hair growth and normal aged horses

Abstract: These findings document that excessive hair growth (hypertrichosis) in PPID-affected horses is due to persistence of hair follicles in A. Furthermore, treatment with pergolide improved shedding and reduced the percentage of A follicles in PPID-affected horses.

Cited by 25 publications

References 20 publications

Equine pituitary pars intermedia dysfunction: current perspectives on diagnosis and management

Equine pituitary pars intermedia dysfunction: current perspectives on diagnosis and management

Mutually‐induced traumatic alopecia responsive to husbandry modification in two cohabiting donkeys

Effects of hair coat characteristics on radiant surface temperature in horses

Contact Info

Product

Resources

About