Applied Clinical Genetics Case Library
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
What is on your problem list?
- Seborrhea
What is on your differential diagnostics list?
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
What diagnostics/prognostics do you run?
- 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
What is your plan? How will you follow up with this patient?
- 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.
References/Additional Resources
- 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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