Applied Clinical Genetics Case Library
Case 12

Signalment & History
Signalment:
  • 12-month-old 
  • Neutered male 
  • Purebred American Bulldog
History:
  • H/o otitis externa; chronic flaky, erythematous skin and intermittent pruritus, and malodor. Unresponsive to medical management; Diet: beneful free feed; HW Preventive: current on HW/Flea/Tick Prevention; Fecal/Parasite Exam: Submitted 2 months ago–neg. for ova
  • Current Treatments: Janus kinase inhibitor, immunomodulating injection, hydrolyzed diet, essential fatty acid supplementation, oral antifungal medication
Presenting Complaint
  • Chronic skin issues
Physical Exam
  • Temp: 102.2; Pulse: 102; Respiration: pant; MM: p/m; CRT: 2s; BCS: 7/9; Weight: 95.1 lbs; Eyes: wnl; Ears: moderate amount of brown caseous debris accumulated bilaterally with minimal canal erythema; Mouth: Dental Disease = Grade 1; LN’s: wnl; Cardio: wnl; Resp: wnl; Abd: wnl; GI: wnl; MS: wnl; CNS: wnl; Skin: desquamation on lateral aspects of both distal hind limbs, lateral lumbar areas and lateral aspects of both shoulders; no intact pustules; diffusely red skin with brown flakes, malodor, and sensitivity to touch; Lumps: n/a; Urogen: wnl
Primary
  • Primary idiopathic seborrhea
  • Vitamin A-responsive dermatosis
  • Zinc-responsive dermatosis
  • Epidermal dysplasia
  • Canine ichthyosis
  • Sebaceous adenitis
Secondary
  • Microbial (pyoderma, Malassezia, dermatophytosis)
  • Parasitic (flea, cheyletielosis, sarcoptic mange, demodectic mange, pediculosis)
  • Endocrinopathy (hypothyroidism, hyperadrenocorticism)
  • Allergic (food hypersensitivity, atopic dermatitis)
  • Management (poor nutrition, inappropriate medication administration, poor compliance with topical therapies)
  • Metabolic disease (liver disease)
  • Immune mediated disease (adverse drug reaction)
  • Paraneoplastic disorders
  • Cutaneous T-cell lymphoma
  • Genetic screening
  • Skin scrape & cytology
  • Fungal culture
  • Food trial
  • Trying different ectoparasite treatment
  • Full CBC, chemistry, and thyroid testing
Click here to open genetics report
  • Owner elected a confirmatory skin biopsy to diagnose a severe form of ichthyosis. 
  • They will begin managing him with judicious topical therapies (specialized shampoos, moisturizing rinses, and agents to remove excess scale and to reinstate the corneocyte lipid envelope). 
  • Discussed the need for dental cleanings with client.
Outcome
  • Skin concerns were not due to allergies alone. Genetic testing revealed predisposition to ichthyosis. Proper expectations and directed management have begun in light of incorporating genetic testing into clinical tools.
  • Casal ML, Wang P, Mauldin EA, Lin G, Henthorn PS. A Defect in NIPAL4 Is Associated with Autosomal Recessive Congenital Ichthyosis in American Bulldogs. PLoS One. 2017;12(1):e0170708. Published 2017 Jan 25. doi:10.1371/journal.pone.0170708
  • Mauldin EA, Wang P, Evans E, et al. Autosomal Recessive Congenital Ichthyosis in American Bulldogs Is Associated With NIPAL4 (ICHTHYIN) Deficiency. Vet Pathol. 2015;52(4):654-662. doi:10.1177/0300985814551425
  • Briand A, Cochet-Faivre N, Reyes-Gomez E, Jaraud-Darnault A, Tiret L, Chevallier L. NIPAL4 deletion identified in an American Bully with autosomal recessive congenital ichthyosis and response to topical therapy. Vet Med Sci. 2019;5(2):112-117. doi:10.1002/vms3.149
  • E.A. Mauldin, D. Crumrine, M.L. Casal, S. Jeong, L. Opálka, K. Vavrova, et al. Cellular and metabolic basis for the ichthyotic phenotype in NIPAL4 (Ichthyin)-deficient canines Am J Pathol, 188 (2018), pp. 1419-1429. https://doi.org/10.1016/j.ajpath.2018.02.008.
  • Mauldin EA. Canine ichthyosis and related disorders of cornification. Vet Clin North Am Small Anim Pract. 2013;43(1):89-97. doi:10.1016/j.cvsm.2012.09.005
  • https://vgl.ucdavis.edu/test/ichthyosis-gr
  • https://www.sciencedaily.com/releases/2018/07/180705165717.htm#:~:text=No%20effective%20treatments%20currently%20exist,step%20toward%20a%20topical%20therapy

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