CHAPTER 6 SYMPTOM CHECKER (LESIONAL AND REGIONAL DERMATOSES) 61
Testosterone-responsive dermatoses: progressive truncal alopecia of castrated male
dogs.
Sertoli cell tumor: male feminization, gynecomastia, alopecia of perineum and genital
region (Figure 6.29).
Castration-responsive dermatosis: hair loss in collar area, perineum, caudomedial
thighs, flanks.
Topical hormone replacement therapy exposure: more recently recognized cause of
“endocrinopathy” appearance (Figures 6.30, 6.31).
Diabetes mellitus: partial diffuse alopecia, may be associated with miliary dermatitis
in the cat (Figure 6.32).
Color dilution alopecia: thinning of haircoat, associated with folliculitis, progres-
sive, often associated with blue coat color; common in Yorkshire terriers, dobermans,
labradors (Figure 6.33).Follicular dysplasia: slow progressive alopecia (Irish water spaniels, Italian spinones).
Follicular lipidosis: red points, young dogs, rottweilers.
Congenital alopecia: bichon frise, beagle, basset hound, French bulldog, rottweiler;
some breeds selected for this disorder – Chinese crested, Mexican dogs, American
hairless terrier, Abyssinian cat, sphinx cat.Telogen defluxion: associated with stressful event (e.g., pregnancy).
Keratinization disorder: associated with hyperkeratosis and excessive greasiness,
most common in the cocker spaniel (Figure 6.34).
Pemphigus: hair loss accompanied by scale, crust, pustules, erythema.
Cutaneous epitheliotropic lymphoma: scale and alopecia initial stage; progresses to
plaques, nodules, and ulceration, associated with depigmentation of mucous mem-
branes (Figures 6.35–6.37).Feline hereditary hypotrichosis: autosomal recessive, Siamese, Devon rex, Burmese,
birman; thin sparse haircoat.
Feline alopecia universalis: hereditary defect, complete absence of primary hairs,
decreased secondary hairs, thickened epidermis, oily skin, no whiskers, downy fur
at tip of tail, paws, scrotum (sphinx, Canadian hairless).Feline symmetrical alopecia: psychogenic or allergic dermatitis most common
etiology.
Feline thymoma; exfoliative dermatitis, erythematous, nonpruritic, starts on the head
and neck, becomes generalized, older cats.
Feline paraneoplastic alopecia: acute onset, rapidly progressing, ventrally (may also
affect eyes, nose, footpads) complete alopecia, smooth and glistening skin, pancreatic
exocrine adenocarcinomas and bile duct carcinomas (Figure 6.38).Feline lymphocytic mural folliculitis: alopecia, scale, hyperpigmentation,±pruritus
may be a reaction pattern or paraneoplastic syndrome.
Pseudopelade: lymphocytic attack on hair follicle isthmus with resultant alopecia,
nonpruritic, noninflammatory (Figure 6.39).
Alopecia mucinosa: mucinosis of hair follicle outer root sheath and epidermis.
Trichorrhexis nodosa: excessive trauma to the hair, focal hair shaft swelling associated
with cuticular damage.