Nail conditions Mrs Sue Paterson MA Vet MB

Nail conditions Mrs Sue Paterson MA Vet. MB DVD Dip. ECVD RCVS and European Specialist in Veterinary Dermatology Rutland House Veterinary Hospital, St Helens, UK

Structure of the canine claw courtesy of Patel, Forsythe

Nail terms �Onychoclasis – breaking of the claw �Onychocryptosis – ingrown nail �Onychodystrophy – abnormal claw formation �Onychogryphosis – hypertrophy and abnormal curvature of the claw �Onychomedesis – sloughing of the claw �Onychomalacia – softening of the claw �Onychomycosis – fungal infection of the claw �Onychorrhexis – longitudinal striations associated with brittleness and breaking of the claw �Onychoschizia - splitting or lamination of the claw �Paronychia – inflammation or infection of the claw fold

Paronychial disease – involves the nail fold Nail disease – involves the nail

Important to differentiate between diseases of the nails beds and those of the nails Investigation and therapy of each disease is different

Disease of the nail bed – Dogs Bacterial paronychia secondary to allergy, endocrine disease, demodex Malassezia paronychia secondary to allergy or endocrine disease Demodectic paronychia Leishmaniasis Neoplastic Immune mediated S. L. E. Pemphigus foliaceus Bullous pemphigoid Drug eruption

Disease of the nails – Dogs Congenital disease – DEB, Ichthyosis Traumatic injury –RTA Onychomycosis Vasculitis Dermatomyositis Leishmaniasis Idiopathic lupoid onychodystropy

Disease of the nail bed – Cats Bacterial paronychia secondary to allergy or FIV, Fe. LV Malassezia paronychia secondary to allergy or endocrine disease Viral paronychia calici, herpes, pox Demodectic paronychia S. L. E. Pemphigus foliaceus Bullous pemphigoid Drug eruption Neoplastic met bronchial carcinoma

Disease of the nails – Cats Traumatic – RTA Onychomycosis Vasculitis Idiopathic onychodystrophy

Investigation of nail disease �History �Physical examination �Dermatological examination

Examination of nail �Examination of the nail / nail bed is important to establish which structure is affected �In some case paronychial disease and nail disease is present concurrently

Investigation of nail disease �Diagnostic tests �Samples from nail beds – skin scrapes, hair plucks, cytology �Nail trimmings for dermatophytes culture �Removal of nail for histopathology ?

BIOPSY TECHNIQUES

Symmetrical lupoid onychodystrophy

Approach to a nail case �History – breed, age, life style �Physical examination – signs of systemic ill health �Dermatological examination – evidence of involvement of other areas, e. g. face, other mc junctions

Symmetrical lupoid onychodystrophy Aetiology Uncommon to rare immune mediated claw loss Usually young adult - middle aged dogs esp. GSD Initial signs are of loss of 1 – 2 nails but disease is progressive and over weeks to months all claws will slough Replacement claws are usually misshapen, soft, brittle, friable and will slough again without therapy Feet usually painful and dog may be lame This is a diagnosis of exclusion

Initial diagnostic tests �Cytology of any exudate �Bacterial culture of exudate when appropriate �Fungal culture of claw clippings �Bloods if systemic disease is suspected �Biopsy of skin if generalised disease is a potential differential diagnosis �Histopathology of P 3

Initial diagnostic tests �Diagnostic histopathology of P 3 �Hydropic degeneration, apoptosis of individual keratinocytes in basal cell layer, pigentary incontinence, lichenoid interface dermatitis

Symmetrical lupoid onychodystrophy Differential diagnosis Dermatophytosis Trauma Autoimmune disease e. g. pemphigus foliaceus Immune mediated disease – vasculitis, dermatomyositis

Further investigation �A diagnosis of onychodystrophy is made by exclusion of other causes �Removal of all nails by traction should be undertaken �Dog anaesthetised with full analgesia. �The feet are clipped and prepared surgically �Each nail is grasped in turn with a pair of artery forceps and is twisted and pulled to remove it �Cultures taken from nail bed and nail submitted for fungal culture

Post operatively �Dog feet are dressed & hospitalised for 48 hrs �Antibiotics given usually Cephalexin 25 mg/kg bid plus analgesia Tramadol 2 – 5 mg / kg bid �After 24 hours dressings removed, feet gently cleaned – under GA if necessary. No further dressing are applied �Dog sent home initially with more antibiotics, pain relief and a large buster collar

10 day recheck – ongoing tx At 10 days analgesia and antibiotics can be discontinued Ongoing treatment �Immune modulators �Nutritional supplements

10 day recheck – ongoing tx Immune modulators �Tetracycline or Doxycycline and Niacinamide �Glucocorticoids �Azathioprine �Ciclosporine �Pentoxyphylline

10 day recheck – ongoing tx Nutritional supplements �Omega 6 and /or omega 3 EFAs �Biotin

Tetracycline/doxycycline + niacinamide �Dogs < 15 kg Tetracycline 250 mg with Niacinamide 250 mg tid �Dogs > 15 kg Tetracycline 500 mg with Niacinamide 500 mg tid �Alternative to tetracycline - Doxycycline 10 mg/kg sid �Precise mechanism unknown. �Tetracycline and Doxycycline both have antiinflammatory and immune modulating activity �Niacinamide shown to have range of antiinflammatory effects �Combination useful in DLE and pemphigus as well as lupoid onycodystrophy

Glucocorticoids �Have been shown to be useful in many case, only start once any bacterial or fungal infection has been resolved �Dose rate is very variable �Low dose therapy �Prednisolone 0. 5 mg/kg sid/eod po �High dose therapy �Prednisolone 2. 0 mg/kg sid/eod po �Gastric protectants useful if using the higher dose rate

Azathioprine / Cyclosporine Both drugs can be used with or to replace steroids Azathioprine 2 mg/kg po sid up to 3 months until remission is seen then eod. �Dogs must be monitored for changes in liver function and bone marrow Cyclosporine 5 m/kg po sid up to 3 months until remission and then taper to eod or biw �Monitoring not necessary in a healthy dog, but cost may be prohibitive

Omega 6 and /or omega 3 EFAs �Essential fatty acids increasing the suppleness of thin, brittle nails. �Important in dogs when exercising and when nails are cut �Dose 300 mg EPA / 10 kg daily or � 200 mg GLA / 10 kg daily

Pentoxiphylline 10 -24 mg/kg bid/tid �Immunodulatory drug in man useful for treatment of peripheral vascular disease and vasculitis �Been shown to be useful for similar conditions in dogs

Biotin - Human studies �Biotin supplementation increases nail thickness by 25 percent in 63% of a group of patients with brittle nails. (Floersheim GL 1989). �Patients taking biotin daily for 3 -6 mths had reduced brittleness & splitting (Hochman LG et al 1993). �Increased nail thickness as identified by scanning EM was recorded after biotin supplementation. (Colombo VE et al 1990).

Typical combination therapy �Essential fatty acids GLA 200 mg/10 kg sid po or 300 mg/10 kg sid po �Biotin 2. 5 - 3 mg daily/ dog �Prednisolone 0. 5 mg/kg eod po �Pentoxyphylline 10 mg/kg tid po �Continue therapy for 6 weeks then reassess �If dog making progress consider with drawing Pentoxyphylline, continue with other drugs long term

Failure to respond to therapy �Switch to a different immune modulator �Azathioprine �Ciclosporine �Tetracycline / doxycycline with niacinamide �Surgical intervention to amputate all of the claws.