DISCOID lupus erythematosus
(also known as cutaneous lupus
erythematosus) is considered to be
an auto-immune disease and a
benign form of
systemic lupus
erythematosus.
Although rare, it is
one of the more common auto-
immune skin diseases seen in
practice and more cases are seen in
the summer suggesting that UV
light is a contributing factor in the
pathogenesis.
Clinical features
The nasal planum is the site most
commonly affected. More
rarely other parts of the body such as
the lips, periocular skin, bridge of the nose, pinnae and distal limbs are
affected. Lesions may consist of the
following:
- depigmentation
and loss of
cobblestone
appearance of nasal
planum; - the nose may take
on a blue colour followed later by – - erythema;
n scaling; - crusts.
Main differential diagnoses
- Pemphigus erythematosus
- Pemphigus foliaceus
- Dermatomyositis
- Uveodermatologic syndrome. The
nasal planum lesions are very similar
but anterior uveitis develops with the
skin lesions or soon after - Nasal pyoderma
- Demodicosis
Diagnosis
- History
- Physical examination
- Rule out differentials
- Histopathological examination.
Interface dermatitis involving the
dermo-epidermal junction. Apoptosis
of the basal cells may be seen.
Immunofluorescence or
immunohistochemistry will in some
cases demonstrate deposition of
immunoglobulin or complement at the
basement membrane zone.
Treatment
- Avoid sunlight as much as
possible. - Systemic glucocorticoids.
As DLE is a relatively
benign disease
glucocorticoids can be tried
initially at a lower dose than
is usual for auto-immune
diseases. - Topical glucocorticoids.
Topical products are limited in efficacy
due to the dog licking them off. - Topical 0.1% tacrolimus has been
reported to be of benefit in some cases. - Tetracycline-niacinamide in
combination with both given at a dose
of 250mg three times daily for several
months has also been advocated. - Cyclosporine (Atopica, Novartis)
5mg/kg once daily is an option in
severe cases that do not respond to
glucocorticoids or suffer unacceptable
side effects. The drug is not licensed for
this disease and informed consent is
necessary.
Prognosis
The prognosis is good. Many dogs
achieve remission on a short course of
glucocorticoids. Life-long intermittent
treatment is usually necessary
however. Possible sequelae include
permanent depigmentation and
scarring. There have been rare cases
that have developed squamous cell
carcinoma.
Further reading
Hnilica, K. A. (2011) Small Animal
Dermatology. A Color Atlas and Therapeutic
Guide 3rd ed. pp248-250.
Elsevier.
Miller, W. H., Griffin, C. E. and Campbell,
K. L. (2013) In Muller and Kirk’s Small
Animal Dermatology 7th ed. pp459-460.
Elsevier.
