Immune-mediated and Autoimmune Skin Diseases Flashcards
Define autoimmune disease
Specific humoral or cell-mediated immune response against auto(self)-antigens that results in disease
Define immune-mediated disease
Used when skin disease is thought to result from inappropriate inflammation or immune attack in the skin but where a specific humoral or cellular response against self-antigens has not been demostrated
What determines the type of lesion seen in autoimmune/immune-mediated disease?
Nature and location of auto-antigen and associated inflammatory response
Which diseases are characterised by vesicles and bullae?
Diseases that are associated with immune-assaults on the basement membrane or basal keratinocytes
Skin and MM may be affected
What do vesicles and bullae end up looking like clinically and why?
Erosions and ulcers as they are very fragile structures
What are some examples of immune diseases that attack the basement membrane?
Bullous pemphigoid ad pemphigus vulgaris
What is pemphigus foliaceus?
Pustular disease wherein large numbers of neutrophils or eosinophils accumulate within the epidermis and evolve into crusts
What characterise diseases classed as subepidermal vesicular autoimmune diseases?
Target antigen is a protein located in the basement membrane leading to a loss of cohesion between the epidermis and dermis frequently associated with the accumulation of inflammatory cells
What are the primary and secondary lesions associated with subepidermal vesicular autoimmune diseases?
Vesicles or bullae which rapidly rupture to leave erosions and ulcers
Where are lesions of subepidermal vesicular autoimmune diseases located?
Frequently around mucocutaneous junctions, in the axille and groin and may involve the mucous membranes as well
What are some examples of subepidermal vesicular autoimmune diseases?
Bullous pemphigoid (BP) - dogs, cats, pigs, horses Mucous membrane pemphigoid (MMP) - dogs, cats Epidermolysis bullosa acquisita (EBA) - dogs
What are the differential diagnoses for subepidermal vesicular autoimmune diseases?
Other ulcerative autoimmune diseases, drug reactions and epitheliotropic lymphoma
What is the classification of pemphigus foliaceus?
Intra-epidermal pustular disease
What are the primary and secondary lesions seen with pemphigus foliaceus?
Primary = pustules Secondary = crusts, scales, hair loss, erosions and epidermal collarettes
Where does pemphigus foliaceus tend to affect?
Face (ears often first), feet including footpads and often the groin with the disease tending to become generalised
What systemic signs can be seen with pemphigus foliaceus if it is severe?
Fever and depression
What is diagnosis of pemphigus foliaceus made on?
History, signs, biopsy, pustule smears
Histopathology is essential
What are the histological features of interface dermatitis?
Dermo-epidermal junction is obscured by inflammatory cells or hydropic degeneration or a combination of these features
What are some examples of interface dermatitis?
Discoid lupus erythematosus
Erythema multiforme/toxic epidermal necrolysis (TEN)
What dogs are predisposed to discoid lupus erythematosus?
Collies, Shelties, GSD and Huskies
What are the signs of discoid lupus erythematosus?
Depigmentation, scaling and erythema of nose extending to the bridge of the nose and sometimes affecting the ears and periorbital areas
What is an early sign of discoid lupus erythematosus?
Loss of the cobblestone appearance of the nasal planum subsequently with erosion and crusting
What is the histopathological appearance of discoid lupus erythematosus?
Cell-rich, lymphocytic interface dermatitis
What is the treatment for discoid lupus erythematosus?
Avoid sunlight as it exacerbates the disease, topical fluorinated glucocorticoids twice daily, combined oxytetracycline and niacinamide therapy, Vitamin E, systemic prednisolone in severe cases
