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Discoid lupus erythematosus (DLE, lupoid
dermatosis of the nose)
DLE is a sun-aggravated (and probably induced) sterile immune mediated disease that mainly
affects the nasal planum of dogs (and less commonly the muzzle skin, eyelids and paws).
There is likely a hereditary component to the disease as it is seen more frequently in Collies,
Shetland Sheepdogs, Border Collies, and Kelpies.
Diagnosis
DLE is sometimes a diagnostic challenge because there are many diseases of the nose that
can look similar clinically AND on histopathology. This means that biopsy alone is NOT enough
confirm a diagnosis prior to commencement of therapy. What is required is a correlation of a
supportive biopsy with a consistent clinical picture and (importantly) ruling out concurrent or
differential diagnoses. For example, DLE may be aggravated by secondary bacterial infection
and so infection must be treated before a biopsy is taken. A 2-3 week course of cephalexin at
22 mg/kg q12h immediately prior to biopsy should be done to rule out or resolve
mucocutaneous bacterial pyoderma
The most common reason for treatment failure is an INCORRECT DIAGNOSIS. The nasal
planum is one of the most difficult areas to get a diagnostic biopsy from as there is not much
tissue and lesion selection is absolutely critical. It is prudent to discuss ALL cases involving
nasal planum with a dermatologist or consider referral PRIOR to biopsy collection to maximise
the chance the a diagnostic sample first time. The avoids having to repeat the biopsy.
Initial Therapy

Treatment for DLE varies with individuals and the severity of disease. In all cases sun
avoidance between 10am and 4pm is strongly recommended, and any secondary infection
should be adequately treated (if it has not already) if present prior to starting immunomodulatory
therapies.
Mild cases may be managed with sun avoidance alone. Vitamin E supplementation (250-500
units q12h) may also be used although we do not find much success with this.
More moderate to severe cases require a more aggressive approach. If the dog will tolerate
topical medication, Elidel (pimecrolimus) ointment twice daily has worked very well for us. It is a
localised treatment, which is ideal, and is well tolerated and not expensive. Topical
corticosteroids e.g. mometasone (Elocon) ointment may be needed early in treatment to get
faster control of the crusting. Elidel does not penetrate the crusting so well initially.
If a case of DLE has not responded well to topical Elidel with initial Elocon within 6 to 8 weeks,
then referral is indicated.
Systemic Therapy

If DLE has been confirmed by a dermatologist but topical treatment has failed then systemic
treatment may be required. The next step up is doxycycline / vitamin B3 therapy. Niacinamide
or nicotinamide at 250 mg q8h in small dogs < 15kg bodyweight and 500 mg q8h in larger dogs,
and doxycycline at 5-10 mg/kg q24h is used, but response can take up to 6 weeks. Because of
this we frequently will also use prednisolone 0.5 mg/kg once daily on a tapering dose in these
initial phases of therapy to help rapidly resolve clinical lesions. These treatments are used in
conjunction with Elidel and Elocon topically unless there are pet temperament issues that
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preclude use of topicals. Long term the aim is to be able to withdraw prednisolone and taper the
doxycycline to 2.5 mg/kg q24h and the vitamin B3 to q24h, or even less frequent if possible.
This is important because prednisolone, while often effective for improving nasal lesions of
DLE, is likely to cause iatrogenic hyperadrenocroticism with long term use at doses of >
0.25mg/kg eod (and less in some animals).
If none of these therapies are effective then immunosuppression is required and management
by a dermatologist recommended. Plastic surgery with removal of the dorsal nasal planum is an
approach sometimes undertaken in severe cases. This surgery should only be performed by an
experienced surgeon.
Prognosis

Medical management in most cases is lifelong, and the disease rarely resolves permanently
either spontaneously or with therapy. Some dogs will require large doses of
immunosuppressive medication to achieve complete remission of clinical signs but then
maintain well on more benign medication (a good outcome). It is also important to realise that
depigmented regions are at risk of solar induced neoplasia (e.g. SCC) and so this is another
reason to stress to owners the importance of sun avoidance.
T: 03 9887 8844 F: 03 9887 8500
E: [email protected] W: www.melbvet.com.au
 Copyright  2009 Melbourne Veterinary Specialist Centre 

Source: http://www.melbvet.com.au/files/JRK8RE2RDB/Discoid_lupus_erythematosus_DLE_.pdf