What is swine dermatitis, and what are its clinical manifestations?
What exactly is dermatitis? What clinical manifestations does swine dermatitis have?
Dermatitis can be divided into the following three categories:
1. Infectious inflammatory dermatitis:
⟧ A. Viral infections: foot-and-mouth disease vesicles, dermatitis-nephritis syndrome; bacterial infections: streptococcal abscess, staphylococcal disease.
B. Spirochete infections: syphilitic rash; fungal infections: beriberi; parasitic and insect infections: sarcoptic mange
2. Non-infectious inflammatory dermatitis:
A. Allergic factors: contact dermatitis, drug-induced dermatitis, etc.;
B. Papulosquamous: psoriasis (bullous psoriasis)
C. Neurological dysfunction factors: neurodermatitis, stress syndrome;
D. Vasculitic factors: allergic purpura
E. Physical factors: polymorphic light eruption, corns;
F. Sebaceous gland secretion factors: seborrheic dermatitis, acne, rosacea
3. Non-inflammatory dermatitis
A. Metabolic factors: cutaneous amyloidosis, VA deficiency;
B. Hereditary keratotic factors, acrokeratosis verruciformis, tuberous sclerosis
C. Skin tumors: pigmented diseases, hemangioma, lymphoreticular tissue tumors
The mechanism of dermatitis
Dermatitis is caused by the accumulation of certain metabolites; localized proliferation of epidermal or dermal cells; inflammatory edema and various cell infiltrations, etc.
1. Deposition of metabolites: such as cutaneous amyloidosis (comedones), caused by amyloid protein deposition in the dermal papillary layer.
2. Localized proliferation of epidermal or dermal cells: such as dermatofibroma (warts, corns).
3. Dermatitis caused by inflammatory edema: seen in contact dermatitis, etc. (staphylococcal disease).
4. Dermatitis caused by various cells infiltrating the epidermis or dermis:
A. Purulent inflammatory dermatitis: neutrophil infiltration;
B. Chronic inflammatory dermatitis: lymphocyte infiltration
C. Allergic dermatitis: eosinophil infiltration;
D. Tuberculous papules: epithelioid lymphocyte infiltration
E. Syphilitic papules: plasma cell infiltration;
F. Xanthomatosis: foam cell infiltration.
Clinical manifestation forms of “dermatitis”
Divided into acute phase, subacute phase and chronic phase.
1. Acute phase: manifested as erythema, edema, may be accompanied by papules, vesicles or exudation.
Pathological manifestations: intercellular edema of epidermal cells, spongiosis, intraepidermal vesicles.
2. Subacute phase: vesicles, redness and swelling and exudation decrease, crusting and scaling appear.
3. Chronic phase: mainly skin thickening and lichenification, may be accompanied by hyperpigmentation or hypopigmentation
Pathological manifestations: epidermal thickening, acanthosis, lymphocyte infiltration in the dermal papillae.
The three phases often have no obvious boundaries, and some affected pigs may have them coexist simultaneously; some dermatitis does not necessarily go through all three phases.
5 clinically common types of dermatitis that can be classified
1. Contact dermatitis: skin or mucous membranes contact exogenous substances, and an inflammatory reaction occurs immediately at the contact site, manifested as erythema, swelling, papules, vesicles, etc. Such as acid and alkali irritation, etc.
2. Neurodermatitis (chronic lichen): caused by disorders of cortical inhibition and excitation functions, severe itching or lichenoid lesions, related to stress and emotions. Such as stress from regrouping pigs.
3. Drug-induced dermatitis (drug rash): caused by allergic reaction, diffuse, bright red macules or large red papules.
4. Solar dermatitis: a delayed photoallergic disease induced by sunlight (medium- and long-wave ultraviolet rays), divided into: plaque type, eczema type, erythema type, prurigo type, urticaria type, etc.
5. Seborrheic dermatitis (white scaling wind): begins as moist erythematous patches, then becomes greasy scaly map-like patches, and in severe cases exudation, thick crusts, and foul odor. Such as staphylococcus, etc.
Clinically, those with skin lesion characteristics such as macules, papules, vesicles, plaques, erosions, crusts or lichenification that cannot be further classified are collectively referred to as “eczema”.