LUPOID ONYCHODYSTROPHY
- At a glance
- WHAT DOES IT LOOK LIKE?
- WHAT ELSE LOOKS LIKE THIS?
- HOW DO I DIAGNOSE IT?
- HOW DO I MANAGE IT?
- COMMENTS
AT A GLANCE
- The most common inflammatory disease to cause abnormal claws
- The cause of this condition is unknown but is suspected to be hereditary, inflammatory or immune-mediated
- Normally involves multiple nails/claws on all four feet
- Uncommon to rare in dogs
- Most commonly seen in middle aged dogs, 3-8 years of age
- Predisposed breeds include the German Shepherd dog, Rottweiler and Gordon Setter
WHAT DOES IT LOOK LIKE?
- Often starts as an acute onset of claw loss
- May be associated with significant inflammation or purulent discharge from nailbeds
- May also present as dry, distorted claws that do not slough on their own
- Typically, one or two claws are lost first, followed by sloughing of all claws within several weeks to months
- One or more of the following abnormalities are seen over time
- Onychogryphosis- abnormal curvature of the claws
- Onychomadesis- sloughing of claws
- Onychorrhexis- fragmentation of the claws
- Onychoschizia- splitting of the claws
- Inflammation of the nail fold (paronychia) is uncommon unless there is a secondary bacterial infection present
- Other skin abnormalities and systemic illness are not seen
- Dogs with this disease may be asymptomatic or have associated lameness
WHAT ELSE LOOKS LIKE THIS?
- Bacterial claw infection
- Dermatophytosis/deep fungal infection
- Immune-mediated diseases:
- Pemphigus vulgaris
- Bullous pemphigoid
- Lupus erythematosus
- Vasculitis
- Drug eruption
- Neoplasia (squamous cell carcinoma)
- Cryoglobulinemia or cold agglutinin disease
HOW DO I DIAGNOSE IT?
- History and clinical signs
- Fungal culture to rule out dermatophytosis
- Skin cytology/culture if significant paronychia is noted
- Surgical amputation or biopsy of an affected P3 for dermatohistopathology:
- Hydropic degeneration of the basal cell layer
- Lichenoid interface dermatitis
- Pigmentary incontinence
HOW DO I MANAGE IT?
General information
- Treatment will often take up to 12 weeks to see significant clinical response
- If there is minimal response after 6-8 weeks, medications can added to the current protocol or changed altogether
- Treatment should be continued for a minimum of 6 months but may be necessary for the rest of the dog’s life
Specific treatments
- Manual removal of loose claws (general anesthesia recommended)
- Omega-3 and omega-6 fatty acids
- 180mg EPA/5 kg every 24 hours
- Often used in combination with vitamin E
- Vitamin E
- 200-400 IU by mouth every 12 hours
- Tetracycline/Niacinamide
- Dogs weighing less than 10kg- 250mg of each by mouth every 8 hours
- Dogs weighing more than 10kg- 500mg of each by mouth every 8 hours
- This can be tapered to every 12 hours after noticeable nail regrowth
- Doxycycline at 5-10 mg/kg by mouth every12-24h can be used in place of tetracycline
- Pentoxifylline
- 10-25mg/kg by mouth every 8-12 hours
- Cyclosporine
- 5-10 mg/kg by mouth every 24 hours
- Tapered to lowest dose possible that prevents relapse
- Prednisone
- Often reserved for cases that have failed other treatments
- 2-4 mg/kg/day for approximately 2-4 weeks, then tapered slowly to reach the lowest every other dose that prevents relapse
- Azathioprine
- 1.1-2.2 mg/kg by mouth every 24 to 48 hours
- Monitor CBC and liver enzymes every 2 weeks until disease is in remission and dose has been decreased
- Frequent trimming of claws (about every 2 weeks) to prevent further cracks
- Treatment with appropriate antibiotics if secondary bacterial paronychia is present
- Onychectomy may be considered for refractory cases associated with onychalgia (pain)
- Consider a food elimination trial if there is an suspicion of an adverse food reaction based on history and diagnostics
- Overall prognosis is good but claws may continue to break easily and remain deformed
COMMENTS
- Also called symmetric lupoid onychitis due to the presence of inflammation involving the claws
- Lupoid onychodystrophy is the most common inflammatory disease that leads to abnormal claws and eventual claw loss.
- Diagnosis is often based on history and clinical signs although surgical removal and histopathology of an affected P3 is helpful for definitive diagnosis
- A variety of therapies can be used- one or multiple modalities of treatments can be used to treat the condition
- It will often take up to 3 months of treatment to see significant clinical response
- Some dogs will need lifelong therapy to maintain remission
Further Reading and References
- Hnilica KA. Symmetrical Lupoid Onychodystrophy. In: Small Animal Dermatology- A Color Atlas and Therapeutic Guide. 3rd Edition. St. Louis: WB Saunders, 2011. p 425-427..
- Miller WH Jr, Griffin CE, Campbell KL. Symmetric Lupoid Onychitis. In: Muller and Kirk’s Small Animal Dermatology. 7th edition. Philadelphia: WB Saunders; 2013. p. 734-739.
abscess
A discrete swelling containing purulent material, typically in the subcutis
alopecia
Absence of hair from areas where it is normally present; may be due to folliculitis, abnormal follicle cycling, or self-trauma
alopecia (“moth-eaten”)
well-circumscribed, circular, patchy to coalescing alopecia, often associated with folliculitis
angioedema
Regional subcutaneous edema
annular
Ring-like arrangement of lesions
atrophy
Thinning of the skin or other tissues
bulla
Fluid-filled elevation of epidermis, >1cm
hemorrhagic bullae
Blood-filled elevation of epidermis, >1cm
comedo
dilated hair follicle filled with keratin, sebum
crust
Dried exudate and keratinous debris on skin surface
cyst
Nodule that is epithelial-lined and contains fluid or solid material.
depigmentation
Extensive loss of pigment
ecchymoses
Patches due to hemorrhage >1cm
epidermal collarettes
Circular scale or crust with erythema, associated with folliculitis or ruptured pustules or vesicles
erosion
Defect in epidermis that does not penetrate basement membrane. Histopathology may be needed to differentiate from ulcer.
erythema
Red appearance of skin due to inflammation, capillary congestion
eschar
Thick crust often related to necrosis, trauma, or thermal/chemical burn
excoriation
Erosions and/or ulcerations due to self-trauma
fissure
Excessive stratum corneum, confirmed via histopathology. This term is often used to describe the nasal planum and footpads.
fistula
Ulcer on skin surface that originates from and is contiguous with tracts extending into deeper, typically subcutaneous tissues
follicular casts
Accumulation of scale adherent to hair shaft
hyperkeratosis
Excessive stratum corneum, confirmed via histopathology. This term is often used to describe the nasal planum and footpads.
hyperpigmentation
Increased melanin in skin, often secondary to inflammation
hypopigmentation
Partial pigment loss
hypotrichosis
Lack of hair due to genetic factors or defects in embryogenesis.
leukoderma
Lack of cutaneous pigment
leukotrichia
Loss of hair pigment
lichenification
Thickening of the epidermis, often due to chronic inflammation resulting in exaggerated texture
macule
Flat lesion associated with color change <1cm
melanosis
Increased melanin in skin, may be secondary to inflammation.
miliary
Multifocal, papular, crusting dermatitis; a descriptive term, not a diagnosis
morbiliform
A erythematous, macular, papular rash; the erythematous macules are typically 2-10 mm in diameter with coalescence to form larger lesions in some areas
nodule
A solid elevation >1cm
onychodystrophy
Abnormal nail morphology due to nail bed infection, inflammation, or trauma; may include: Onychogryphosis, Onychomadesis, Onychorrhexis, Onychoschizia
onychogryphosis
Abnormal claw curvature; secondary to nail bed inflammation or trauma
onychomadesis
Claw sloughing due to nail bed inflammation or trauma
onychorrhexis
Claw fragmentation due to nail bed inflammation or trauma
onychoschizia
Claw splitting due to nail bed inflammation or trauma
papule
Solid elevation in skin ≤1cm
papules
Solid elevation in skin ≤1cm
paronychia
Inflammation of the nail fold
patch
Flat lesion associated with color change >1cm
petechiae
Small erythematous or violaceous lesions due to dermal bleeding
phlebectasia
Venous dilation; most commonly associated with hypercortisolism
plaques
Flat-topped elevation >1cm formed of coalescing papules or dermal infiltration
pustule
Raised epidermal infiltration of pus
reticulated
Net-like arrangement of lesions
scale
Accumulation of loose fragments of stratum corneum
scar
Fibrous tissue replacing damaged cutaneous and/or subcutaneous tissues
serpiginous
Undulating, serpentine (snake-like) arrangement of lesions
telangiectasia
Permanent enlargement of vessels resulting in a red or violet lesion (rare)
ulcer
A defect in epidermis that penetrates the basement membrane. Histopathology may be needed to differentiate from an erosion.
urticaria
Wheals (steep-walled, circumscribed elevation in the skin due to edema ) due to hypersensitivity reaction
vesicle
Fluid-filled elevation of epidermis, <1cm
wheal
Steep-walled, circumscribed elevation in the skin due to edema