Discoid lupus erythematosus
Encyclopedia
Discoid lupus erythematosus (DLE) is an uncommon autoimmune disease
of the basal cell layer
of the skin
. It occurs in humans and cats, more frequently occurring in dog
s. It does not progress to systemic lupus erythematosus
(SLE) in dogs. SLE can also have skin symptoms, but it appears that the two are either separate diseases or DLE is a mild form of SLE. DLE in dogs differs from SLE in humans in that plasma cell
s predominate histologically
instead of T lymphocytes. Because worsening of symptoms occurs with increased ultraviolet
light exposure, sun exposure most likely plays a role in DLE, although certain breeds (see below) are predisposed, so there is probably also a genetic cause. After pemphigus foliaceus
, DLE is the second most common autoimmune skin disease in dogs.
Probably the best-known human sufferer of the condition is the singer Seal
, who contracted it as a child and has distinctive scars on his upper cheeks.
The most common initial symptom is scaling and loss of pigment on the nose. This is found in up to 90 percent of dogs. The surface of the nose becomes smooth gray, and ulcerated, instead of the normal black cobblestone texture. Over time the lips, the skin around the eyes, the ears, and the genitals may become involved. Lesions
may progress to ulceration and lead to tissue destruction. DLE is often worse in summer due to increased sun exposure.
, ringworm, and other types of dermatitis. Biopsy
is required to make the distinction. Histopathologically
, there is inflammation
at the dermoepidermal junction
and degeneration of the basal cell layer. Unlike in SLE, an anti-nuclear antibody
test is usually negative.
, which is toxic to dogs) is important. Topical therapy includes corticosteroid
use. Oral vitamin E
or omega-3
and omega-6 fatty acid
s are also used. More refractory cases may require the use of oral niacinamide
and tetracycline, corticosteroids, azathioprine
, or chlorambucil
. Treatment is often lifelong, but there is a good prognosis
for long-term remission.
Autoimmune disease
Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the body actually attacks its own cells. The immune system mistakes some part of the body as a pathogen and attacks it. This may be restricted to...
of the basal cell layer
Stratum germinativum
The stratum basale is the deepest layer of the five layers of the epidermis, which is the outer covering of skin in mammals. The stratum basale is a continuous layer of cells...
of the skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
. It occurs in humans and cats, more frequently occurring in dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s. It does not progress to systemic lupus erythematosus
Lupus erythematosus
Lupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...
(SLE) in dogs. SLE can also have skin symptoms, but it appears that the two are either separate diseases or DLE is a mild form of SLE. DLE in dogs differs from SLE in humans in that plasma cell
Plasma cell
Plasma cells, also called plasma B cells, plasmocytes, and effector B cells, are white blood cells which produce large volumes of antibodies. They are transported by the blood plasma and the lymphatic system...
s predominate histologically
Histology
Histology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope...
instead of T lymphocytes. Because worsening of symptoms occurs with increased ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
light exposure, sun exposure most likely plays a role in DLE, although certain breeds (see below) are predisposed, so there is probably also a genetic cause. After pemphigus foliaceus
Pemphigus
Pemphigus is a rare group of blistering autoimmune diseases that affect the skin and mucous membranes.In pemphigus, autoantibodies form against desmoglein. Desmoglein forms the "glue" that attaches adjacent epidermal cells via attachment points called desmosomes...
, DLE is the second most common autoimmune skin disease in dogs.
Probably the best-known human sufferer of the condition is the singer Seal
Seal (musician)
Seal Henry Olusegun Olumide Adeola Samuel , known simply as Seal, is a British soul and R&B singer-songwriter, of Nigerian and Brazilian background. Seal has won numerous music awards throughout his career, including three Brit Awards—winning Best British Male in 1992, four Grammy Awards, and an...
, who contracted it as a child and has distinctive scars on his upper cheeks.
Symptoms
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
may progress to ulceration and lead to tissue destruction. DLE is often worse in summer due to increased sun exposure.
Diagnosis
DLE is easily confused with solar dermatitis, pemphigusPemphigus
Pemphigus is a rare group of blistering autoimmune diseases that affect the skin and mucous membranes.In pemphigus, autoantibodies form against desmoglein. Desmoglein forms the "glue" that attaches adjacent epidermal cells via attachment points called desmosomes...
, ringworm, and other types of dermatitis. Biopsy
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
is required to make the distinction. Histopathologically
Histopathology
Histopathology refers to the microscopic examination of tissue in order to study the manifestations of disease...
, there is inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
at the dermoepidermal junction
Stratum germinativum
The stratum basale is the deepest layer of the five layers of the epidermis, which is the outer covering of skin in mammals. The stratum basale is a continuous layer of cells...
and degeneration of the basal cell layer. Unlike in SLE, an anti-nuclear antibody
Anti-nuclear antibody
Anti-nuclear antibodies are autoantibodies directed against contents of the cell nucleus....
test is usually negative.
Treatment
Avoiding sun exposure and the use of sunscreens (not containing zinc oxideZinc oxide
Zinc oxide is an inorganic compound with the formula ZnO. It is a white powder that is insoluble in water. The powder is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber , lubricants, paints, ointments, adhesives, sealants,...
, which is toxic to dogs) is important. Topical therapy includes corticosteroid
Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...
use. Oral vitamin E
Vitamin E
Vitamin E is used to refer to a group of fat-soluble compounds that include both tocopherols and tocotrienols. There are many different forms of vitamin E, of which γ-tocopherol is the most common in the North American diet. γ-Tocopherol can be found in corn oil, soybean oil, margarine and dressings...
or omega-3
Omega-3 fatty acid
N−3 fatty acids are essential unsaturated fatty acids with a double bond starting after the third carbon atom from the end of the carbon chain....
and omega-6 fatty acid
Omega-6 fatty acid
n−6 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−6 position, that is, the sixth bond, counting from the methyl end.The biological effects of the n−6 fatty acids are largely mediated by their conversion to n-6 eicosanoids...
s are also used. More refractory cases may require the use of oral niacinamide
Nicotinamide
Nicotinamide, also known as niacinamide and nicotinic acid amide, is the amide of nicotinic acid . Nicotinamide is a water-soluble vitamin and is part of the vitamin B group...
and tetracycline, corticosteroids, azathioprine
Azathioprine
Azathioprine is a purine analogue immunosuppressive drug. It is used to prevent organ rejection following organ transplantation and to treat a vast array of autoimmune diseases, including rheumatoid arthritis, pemphigus, inflammatory bowel disease , multiple sclerosis, autoimmune hepatitis, atopic...
, or chlorambucil
Chlorambucil
Chlorambucil is a chemotherapy drug that has been mainly used in the treatment of chronic lymphocytic leukemia...
. Treatment is often lifelong, but there is a good prognosis
Prognosis
Prognosis is a medical term to describe the likely outcome of an illness.When applied to large statistical populations, prognostic estimates can be very accurate: for example the statement "45% of patients with severe septic shock will die within 28 days" can be made with some confidence, because...
for long-term remission.
Commonly affected dog breeds
- CollieCollieThe collie is a distinctive type of herding dog, including many related landraces and formal breeds. It originates in Scotland and Northern England. It is a medium-sized, fairly lightly built dog with a pointed snout, and many types have a distinctive white pattern over the shoulders. Collies...
- German Shepherd DogGerman Shepherd DogThe German Shepherd Dog , also known as an Alsatian or just the German Shepherd, is a breed of large-sized dog that originated in Germany. The German Shepherd is a relatively new breed of dog, with its origin dating to 1899. As part of the Herding Group, the German Shepherd is a working dog...
- Shetland SheepdogShetland SheepdogThe Shetland Sheepdog, often known as the Sheltie, is a breed of herding dog.They are small to medium dogs, and come in a variety of colors, such as sable/white, tri-color, and blue merle. They are vocal, excitable, energetic dogs who are always willing to please and work hard...
- Siberian HuskySiberian HuskyThe Siberian Husky is a medium-size, dense-coat working dog breed that originated in north-eastern Siberia. The breed belongs to the Spitz genetic family...
- Brittany Spaniel
- German Shorthaired PointerGerman Shorthaired PointerThe German shorthaired pointer is a breed of dog developed in the 19th century in Germany for hunting.The breed is streamlined yet powerful with strong legs that make it able to move rapidly and turn quickly. It has moderately long floppy ears set high on the head. Its muzzle is long, broad, and...