Podcast
Questions and Answers
Which layer of the skin serves as a physical barrier and is involved in temperature regulation?
Which layer of the skin serves as a physical barrier and is involved in temperature regulation?
- Epidermis (correct)
- Subcutis
- Dermis
- Hypodermis
The skin is the smallest organ in the body.
The skin is the smallest organ in the body.
False (B)
What is the primary reason for veterinary consultations regarding skin disease?
What is the primary reason for veterinary consultations regarding skin disease?
Cosmetic and economic importance
The skin consists of three layers: Epidermis, dermis, and __________.
The skin consists of three layers: Epidermis, dermis, and __________.
Match the skin layers with their descriptions:
Match the skin layers with their descriptions:
What is a significant factor in the diagnosis of skin diseases?
What is a significant factor in the diagnosis of skin diseases?
Deep bacterial infections are less serious than superficial bacterial infections.
Deep bacterial infections are less serious than superficial bacterial infections.
List one autoimmune disease associated with the skin.
List one autoimmune disease associated with the skin.
What is the major disadvantage of a skin biopsy?
What is the major disadvantage of a skin biopsy?
Itchy dogs are generally good candidates for a skin biopsy.
Itchy dogs are generally good candidates for a skin biopsy.
What is the recommended number of skin biopsy samples to be collected for increased diagnostic accuracy?
What is the recommended number of skin biopsy samples to be collected for increased diagnostic accuracy?
Photosensitization causes damage primarily in the ______ cells of the skin.
Photosensitization causes damage primarily in the ______ cells of the skin.
What is the primary function of the keratin layer in the epidermis?
What is the primary function of the keratin layer in the epidermis?
The basal cell layer of the epidermis contains cells that can divide indefinitely.
The basal cell layer of the epidermis contains cells that can divide indefinitely.
Match the following types of photosensitivity with their descriptions:
Match the following types of photosensitivity with their descriptions:
What is the term for hair loss?
What is the term for hair loss?
Which diagnostic test allows for a diagnosis of demodicosis?
Which diagnostic test allows for a diagnosis of demodicosis?
Exposure to the sun only causes chronic skin lesions.
Exposure to the sun only causes chronic skin lesions.
The skin lesions caused by inflammation within the dermis are called __________.
The skin lesions caused by inflammation within the dermis are called __________.
What is the purpose of including a detailed history when submitting skin biopsies?
What is the purpose of including a detailed history when submitting skin biopsies?
Match the type of skin lesion with its definition.
Match the type of skin lesion with its definition.
A ______ punch is recommended to take a skin biopsy.
A ______ punch is recommended to take a skin biopsy.
What is anagen?
What is anagen?
What feature helps to distinguish photosensitization clinically?
What feature helps to distinguish photosensitization clinically?
Dermatosis refers to inflammation within the dermis.
Dermatosis refers to inflammation within the dermis.
Spring eczema in calves is typically severe and progresses quickly.
Spring eczema in calves is typically severe and progresses quickly.
What is the process called when mature squames slough off the skin?
What is the process called when mature squames slough off the skin?
The __________ are responsible for the production of hair.
The __________ are responsible for the production of hair.
What can be sent with biopsy submissions to assist in diagnosis?
What can be sent with biopsy submissions to assist in diagnosis?
All skin diseases will become infected by the ______ present on the skin.
All skin diseases will become infected by the ______ present on the skin.
Match the term with its definition.
Match the term with its definition.
Which of the following is NOT a type of photosensitivity?
Which of the following is NOT a type of photosensitivity?
Which layer of skin primarily contains adipose tissue?
Which layer of skin primarily contains adipose tissue?
Sequentially taking a thorough clinical history is unimportant in diagnosing skin diseases.
Sequentially taking a thorough clinical history is unimportant in diagnosing skin diseases.
Which method can be used to obtain diagnostic samples for skin diseases?
Which method can be used to obtain diagnostic samples for skin diseases?
Inflammation of the hypodermis is known as __________.
Inflammation of the hypodermis is known as __________.
What does 'pigmentary incontinence' refer to?
What does 'pigmentary incontinence' refer to?
What type of photosensitization is commonly caused by the ingestion of sporidesmin toxin in New Zealand sheep and cattle?
What type of photosensitization is commonly caused by the ingestion of sporidesmin toxin in New Zealand sheep and cattle?
Dogs are the only domestic animals that develop melanomas as a result of sun exposure.
Dogs are the only domestic animals that develop melanomas as a result of sun exposure.
What is the clinical name for the sunburn observed in sheep due to secondary photosensitization?
What is the clinical name for the sunburn observed in sheep due to secondary photosensitization?
Increased serum gamma-glutamyl transferase (GGT) is used to confirm the presence of __________ photosensitization.
Increased serum gamma-glutamyl transferase (GGT) is used to confirm the presence of __________ photosensitization.
Match the condition with its corresponding type:
Match the condition with its corresponding type:
What are common areas predisposed to sunburn in sheep?
What are common areas predisposed to sunburn in sheep?
Chronic sun exposure primarily leads to the development of neoplasia in various domestic animals.
Chronic sun exposure primarily leads to the development of neoplasia in various domestic animals.
What fungus produces the sporidesmin toxin that causes secondary photosensitization in New Zealand?
What fungus produces the sporidesmin toxin that causes secondary photosensitization in New Zealand?
The excessive grooming behavior in cats leading to hair shaft breakage is known as __________.
The excessive grooming behavior in cats leading to hair shaft breakage is known as __________.
What is a common clinical manifestation resulting from acral lick dermatitis in dogs?
What is a common clinical manifestation resulting from acral lick dermatitis in dogs?
Skin fold dermatitis occurs only in dogs.
Skin fold dermatitis occurs only in dogs.
What is a characteristic histological finding in feline psychogenic alopecia?
What is a characteristic histological finding in feline psychogenic alopecia?
Thermal burns can be classified into ______ degrees based on their severity.
Thermal burns can be classified into ______ degrees based on their severity.
Match the condition to its description:
Match the condition to its description:
Which of the following diseases is commonly referred to as puppy pyoderma?
Which of the following diseases is commonly referred to as puppy pyoderma?
What is the primary factor contributing to frostbite in animals?
What is the primary factor contributing to frostbite in animals?
Superficial pustular dermatitis is a contagious disease.
Superficial pustular dermatitis is a contagious disease.
What bacterium is responsible for exudative epidermatitis of pigs?
What bacterium is responsible for exudative epidermatitis of pigs?
Cold agglutination disease primarily affects cats and can occur even during moderately cold temperatures.
Cold agglutination disease primarily affects cats and can occur even during moderately cold temperatures.
The disease commonly seen in sheep due to moisture trapped in the fleece is called _____ rot.
The disease commonly seen in sheep due to moisture trapped in the fleece is called _____ rot.
What is the most important part of the skin's physical barrier against bacteria?
What is the most important part of the skin's physical barrier against bacteria?
In _________, an abnormal composition of plasma proteins causes blood agglutination in cats.
In _________, an abnormal composition of plasma proteins causes blood agglutination in cats.
What is the primary cause of pyotraumatic dermatitis?
What is the primary cause of pyotraumatic dermatitis?
Which of the following can disrupt the skin's chemical barrier?
Which of the following can disrupt the skin's chemical barrier?
Dermatophilosis occurs exclusively in dogs.
Dermatophilosis occurs exclusively in dogs.
What environmental factor is a predisposing cause of equine pastern dermatitis?
What environmental factor is a predisposing cause of equine pastern dermatitis?
Bacteria can cause disease without any skin disorder present.
Bacteria can cause disease without any skin disorder present.
Match the skin infection with its description:
Match the skin infection with its description:
The bacterium involved in dermatophilosis is called _____ congolensis.
The bacterium involved in dermatophilosis is called _____ congolensis.
What is a common nicknamed form of equine pastern dermatitis?
What is a common nicknamed form of equine pastern dermatitis?
What type of bacteria commonly cause skin infections in companion animals?
What type of bacteria commonly cause skin infections in companion animals?
Match the following diseases with their associated causative agents:
Match the following diseases with their associated causative agents:
Superficial bacterial infections are typically confined to the _________.
Superficial bacterial infections are typically confined to the _________.
Foot rot is caused exclusively by one type of bacterium.
Foot rot is caused exclusively by one type of bacterium.
What is often necessary for the clinical cure of most bacterial skin diseases?
What is often necessary for the clinical cure of most bacterial skin diseases?
Most bacterial skin diseases will not recur if proper treatments are provided.
Most bacterial skin diseases will not recur if proper treatments are provided.
Which bacterial infection is particularly common due to cat bites?
Which bacterial infection is particularly common due to cat bites?
What environmental condition increases the likelihood of frostbite in animals?
What environmental condition increases the likelihood of frostbite in animals?
Infections of penetrating wounds can lead to the formation of _____ and pyoderma.
Infections of penetrating wounds can lead to the formation of _____ and pyoderma.
What is an effective treatment approach for dermatophilosis?
What is an effective treatment approach for dermatophilosis?
Bacteria such as __________ can cause superficial pustular dermatitis, particularly in young animals.
Bacteria such as __________ can cause superficial pustular dermatitis, particularly in young animals.
Name one common underlying cause of pyotraumatic dermatitis.
Name one common underlying cause of pyotraumatic dermatitis.
Which season is most likely to see an increase in cases of cold agglutination disease in cats?
Which season is most likely to see an increase in cases of cold agglutination disease in cats?
Hair shafts are a significant part of the skin's defenses against bacterial infection.
Hair shafts are a significant part of the skin's defenses against bacterial infection.
What is the most common cause of dermal infection with mycobacteria in animals?
What is the most common cause of dermal infection with mycobacteria in animals?
Feline leprosy is caused exclusively by biting flies.
Feline leprosy is caused exclusively by biting flies.
What visible characteristic can be found in lesions caused by botryomycosis?
What visible characteristic can be found in lesions caused by botryomycosis?
Pox viruses cause localized skin disease in many food animal and avian species, but they are most pathogenic in __________.
Pox viruses cause localized skin disease in many food animal and avian species, but they are most pathogenic in __________.
Match the following diseases with their associated viruses or causative agents:
Match the following diseases with their associated viruses or causative agents:
Which of the following is a common disease associated with herpes viruses in cattle?
Which of the following is a common disease associated with herpes viruses in cattle?
Telecom infections are primarily the result of viral agents.
Telecom infections are primarily the result of viral agents.
What type of lesions do herpes viruses cause in animals?
What type of lesions do herpes viruses cause in animals?
What is the most common skin neoplasm of horses?
What is the most common skin neoplasm of horses?
Feline sarcoids are a common neoplasm typically found on the ears and paws of cats.
Feline sarcoids are a common neoplasm typically found on the ears and paws of cats.
Infections with papillomaviruses most often result in __________.
Infections with papillomaviruses most often result in __________.
Match the viral disease to its primary affected animal:
Match the viral disease to its primary affected animal:
What is commonly known as ringworm?
What is commonly known as ringworm?
Which of the following conditions is most associated with dermatitis due to herpes viruses?
Which of the following conditions is most associated with dermatitis due to herpes viruses?
Equine sarcoids are caused by an infection of __________ papillomavirus.
Equine sarcoids are caused by an infection of __________ papillomavirus.
Which dog breed has a predisposition for developing viral plaques?
Which dog breed has a predisposition for developing viral plaques?
Surgical excision is an effective long-term solution for recurring lesions caused by mycobacterial infections.
Surgical excision is an effective long-term solution for recurring lesions caused by mycobacterial infections.
All cats can potentially develop Malassezia dermatitis.
All cats can potentially develop Malassezia dermatitis.
What do bovine fibropapillomas typically develop around in bulls?
What do bovine fibropapillomas typically develop around in bulls?
Bovine herpes viruses can cause inflammation of the __________ due to milking irritation.
Bovine herpes viruses can cause inflammation of the __________ due to milking irritation.
What fungal organism is the most common cause of Dermatophytosis?
What fungal organism is the most common cause of Dermatophytosis?
Symptoms of cutaneous fungal infections in animals typically include areas of crusting and __________.
Symptoms of cutaneous fungal infections in animals typically include areas of crusting and __________.
Match the following diseases with their associated organisms:
Match the following diseases with their associated organisms:
What can be a consequence of viral plaques in dogs?
What can be a consequence of viral plaques in dogs?
Fungal infections in animals are typically pruritic (itchy).
Fungal infections in animals are typically pruritic (itchy).
What are the three categories of fungal skin diseases?
What are the three categories of fungal skin diseases?
Cryptococcosis commonly accesses the body via the __________.
Cryptococcosis commonly accesses the body via the __________.
Where do lesions from Cryptococcosis typically develop on the body?
Where do lesions from Cryptococcosis typically develop on the body?
What percentage of people with AIDS develop an infection with C. neoformans?
What percentage of people with AIDS develop an infection with C. neoformans?
C. neoformans infections are most commonly associated with healthy individuals.
C. neoformans infections are most commonly associated with healthy individuals.
Which specific type of mites are primarily responsible for demodicosis in dogs?
Which specific type of mites are primarily responsible for demodicosis in dogs?
Demodicosis is common in dogs, particularly breeds with a short, dense __________ coat.
Demodicosis is common in dogs, particularly breeds with a short, dense __________ coat.
What is the primary reason for the hair loss in dogs with demodicosis?
What is the primary reason for the hair loss in dogs with demodicosis?
Pruritus is a common feature of demodicosis in dogs.
Pruritus is a common feature of demodicosis in dogs.
What is the primary mode of transmission for sarcoptic mange?
What is the primary mode of transmission for sarcoptic mange?
Sarcoptic mange is best considered a __________ reaction.
Sarcoptic mange is best considered a __________ reaction.
Which of the following is NOT associated with sarcoptic mange?
Which of the following is NOT associated with sarcoptic mange?
A skin scraping is a highly effective method for diagnosing sarcoptic mange.
A skin scraping is a highly effective method for diagnosing sarcoptic mange.
What is the main aim of treatment for demodicosis in older dogs?
What is the main aim of treatment for demodicosis in older dogs?
Match the following skin diseases with their descriptions:
Match the following skin diseases with their descriptions:
What are typical clinical signs of demodicosis in dogs?
What are typical clinical signs of demodicosis in dogs?
The treatment of ectoparasites is an important source of __________ for veterinarians.
The treatment of ectoparasites is an important source of __________ for veterinarians.
What is the most common allergen responsible for dermatitis in dogs and cats?
What is the most common allergen responsible for dermatitis in dogs and cats?
Atopy is primarily caused by food allergens.
Atopy is primarily caused by food allergens.
Which body areas are most commonly affected by flea allergy dermatitis?
Which body areas are most commonly affected by flea allergy dermatitis?
Mosquito-bite hypersensitivity leads to ulcerated lesions on the non-haired skin of the ______.
Mosquito-bite hypersensitivity leads to ulcerated lesions on the non-haired skin of the ______.
Match the following allergic conditions with their descriptions:
Match the following allergic conditions with their descriptions:
What characterizes urticaria (hives) in animals?
What characterizes urticaria (hives) in animals?
Food allergies typically result in a consistent distribution of lesions on the body.
Food allergies typically result in a consistent distribution of lesions on the body.
What histological feature is often seen in flea allergy dermatitis?
What histological feature is often seen in flea allergy dermatitis?
Eosinophilic plaques in feline allergic dermatitis often appear on the ______ abdomen.
Eosinophilic plaques in feline allergic dermatitis often appear on the ______ abdomen.
Match the following allergic reactions with their descriptions:
Match the following allergic reactions with their descriptions:
Which allergic condition is characterized by the strong genetic basis?
Which allergic condition is characterized by the strong genetic basis?
Equine allergies generally present as generalized skin reactions.
Equine allergies generally present as generalized skin reactions.
What type of cells mainly infiltrate eosinophilic plaques in allergic dermatitis?
What type of cells mainly infiltrate eosinophilic plaques in allergic dermatitis?
Which of the following are the most common areas affected by human-adapted S scabiei mites?
Which of the following are the most common areas affected by human-adapted S scabiei mites?
Human-adapted S scabiei mites can spontaneously resolve without treatment.
Human-adapted S scabiei mites can spontaneously resolve without treatment.
Atopy is estimated to account for around ______% of all canine skin disease.
Atopy is estimated to account for around ______% of all canine skin disease.
What are the two categories of diseases caused by flies?
What are the two categories of diseases caused by flies?
Immune-mediated skin diseases are more common in __________ animals.
Immune-mediated skin diseases are more common in __________ animals.
What release is caused by mast cell degranulation in allergic reactions?
What release is caused by mast cell degranulation in allergic reactions?
All allergens produce distinct histological lesions.
All allergens produce distinct histological lesions.
Identify one unique manifestation of allergic skin disease found in cats.
Identify one unique manifestation of allergic skin disease found in cats.
Allergic reactions in animals are often associated with overproduction of _______.
Allergic reactions in animals are often associated with overproduction of _______.
Match the following types of allergens with their descriptions:
Match the following types of allergens with their descriptions:
Which of the following can trigger allergic skin disease in animals?
Which of the following can trigger allergic skin disease in animals?
Canine allergies typically do not cause lesions due to self-trauma.
Canine allergies typically do not cause lesions due to self-trauma.
What histological cell types are predominant in allergic skin disease?
What histological cell types are predominant in allergic skin disease?
The skin lesions created by chronic allergic reactions are often __________ and __________.
The skin lesions created by chronic allergic reactions are often __________ and __________.
Which type of skin conditions are autoimmune diseases commonly associated with?
Which type of skin conditions are autoimmune diseases commonly associated with?
Flea infestation can cause anemia in older animals.
Flea infestation can cause anemia in older animals.
Which of the following is an autoimmune disease affecting dogs and cats?
Which of the following is an autoimmune disease affecting dogs and cats?
Pemphigus foliaceus can develop secondary to drug therapy.
Pemphigus foliaceus can develop secondary to drug therapy.
What is the primary treatment recommendation for allergic reactions in pets?
What is the primary treatment recommendation for allergic reactions in pets?
The disease characterized by the loss of cellular adhesion in the epidermis due to antibodies is called __________.
The disease characterized by the loss of cellular adhesion in the epidermis due to antibodies is called __________.
Match the following conditions with their characteristics:
Match the following conditions with their characteristics:
What body area is typically first affected in pemphigus foliaceus?
What body area is typically first affected in pemphigus foliaceus?
Discoid lupus erythematosus is considered a true autoimmune disease.
Discoid lupus erythematosus is considered a true autoimmune disease.
What is the commonly affected area in dogs with discoid lupus erythematosus?
What is the commonly affected area in dogs with discoid lupus erythematosus?
Autoimmune skin disease constitutes what percentage of cases in companion animal dermatology referral centers? __________
Autoimmune skin disease constitutes what percentage of cases in companion animal dermatology referral centers? __________
Match the breed with the skin conditions they are predisposed to:
Match the breed with the skin conditions they are predisposed to:
What is the primary characteristic of primary seborrhea in dogs?
What is the primary characteristic of primary seborrhea in dogs?
What diagnostic test is required for definitive diagnosis of autoimmune diseases?
What diagnostic test is required for definitive diagnosis of autoimmune diseases?
Juvenile sterile granulomatous dermatitis involves bacterial infections.
Juvenile sterile granulomatous dermatitis involves bacterial infections.
Most dogs with hypothyroidism display symmetrical alopecia.
Most dogs with hypothyroidism display symmetrical alopecia.
What is the mean age at diagnosis for pemphigus foliaceus in dogs?
What is the mean age at diagnosis for pemphigus foliaceus in dogs?
What causes the unpleasant odor associated with seborrhea?
What causes the unpleasant odor associated with seborrhea?
In cases of hypothyroidism, skin lesions may include loss of hair in areas of __________.
In cases of hypothyroidism, skin lesions may include loss of hair in areas of __________.
Feline plasma cell pododermatitis is also referred to as __________.
Feline plasma cell pododermatitis is also referred to as __________.
Match the following skin conditions with their characteristics:
Match the following skin conditions with their characteristics:
Which of the following is NOT a feature of pemphigus foliaceus?
Which of the following is NOT a feature of pemphigus foliaceus?
Which treatment is commonly effective for juvenile sterile granulomatous dermatitis?
Which treatment is commonly effective for juvenile sterile granulomatous dermatitis?
Secondary seborrhea will resolve only after treating the primary skin disease.
Secondary seborrhea will resolve only after treating the primary skin disease.
What age group of puppies is most commonly affected by juvenile sterile granulomatous dermatitis?
What age group of puppies is most commonly affected by juvenile sterile granulomatous dermatitis?
Seborrhea can occur as a primary or __________ process.
Seborrhea can occur as a primary or __________ process.
What histological finding is common in cases of seborrhea?
What histological finding is common in cases of seborrhea?
What is the primary histological change observed in dogs with non-thyroid endocrinopathies?
What is the primary histological change observed in dogs with non-thyroid endocrinopathies?
Histological examination can differentiate between the four non-thyroid endocrinopathies in dogs.
Histological examination can differentiate between the four non-thyroid endocrinopathies in dogs.
Which endocrinopathy in dogs is characterized by alopecia that spares the head and extremities?
Which endocrinopathy in dogs is characterized by alopecia that spares the head and extremities?
In dogs, cyclical flank alopecia is believed to be triggered by changes in the ______.
In dogs, cyclical flank alopecia is believed to be triggered by changes in the ______.
Match the following endocrinopathies with their descriptions:
Match the following endocrinopathies with their descriptions:
What is a clinical feature of starvation in food animals?
What is a clinical feature of starvation in food animals?
Calcinosis cutis is a common finding in horses with PPID.
Calcinosis cutis is a common finding in horses with PPID.
What is the treatment recommendation for cyclical flank alopecia?
What is the treatment recommendation for cyclical flank alopecia?
The skin lesions associated with non-thyroid endocrinopathies are characterized by ________ symmetrical alopecia.
The skin lesions associated with non-thyroid endocrinopathies are characterized by ________ symmetrical alopecia.
What type of alopecia is commonly seen in dogs with sex hormone responsive dermatosis?
What type of alopecia is commonly seen in dogs with sex hormone responsive dermatosis?
Dystrophic calcification is the only unique condition in dogs related to chronic hyperadrenocorticism.
Dystrophic calcification is the only unique condition in dogs related to chronic hyperadrenocorticism.
What causes alopecia in growth hormone responsive dermatosis in mature animals?
What causes alopecia in growth hormone responsive dermatosis in mature animals?
Horses with PPID fail to shed their winter coats and appear excessively ______.
Horses with PPID fail to shed their winter coats and appear excessively ______.
Match the following disorders with their related species:
Match the following disorders with their related species:
Study Notes
Pathology of the Skin: Learning Objectives
- Understand pathogenesis and diagnosis of common skin diseases.
- Recognize the role of clinical history and examination in skin disease diagnosis; value of skin biopsy.
- Differentiate development of superficial vs. deep bacterial skin infections.
- Grasp genetic basis and pathogenesis of allergic skin diseases in animals.
- Identify variations in clinical presentation of allergic skin diseases across dogs, cats, and horses.
- Comprehend pathogenesis of key autoimmune skin diseases, including pemphigoid diseases and discoid lupus erythematosus.
- Identify histological lesions related to canine non-thyroid endocrinopathies; list associated diseases.
- Know tests for diagnosing neoplastic and non-neoplastic skin tumors.
General Considerations
- Skin is the largest organ; important for cosmetic and economic reasons in veterinary consultation.
- Skin diseases can be primary or secondary to other bodily diseases.
- Limited skin responses complicate gross differentiation between diseases.
Function and Normal Histology of the Skin
- Skin functions: barrier, temperature regulation, blood pressure, serum electrolyte regulation, vitamin D production, and immune system component.
- Normal skin consists of three layers: Epidermis (5-50 cells thick), Dermis, Hypodermis.
- Basal cells in the epidermis are stem cells that differentiate into keratinized cells at the surface.
- Hair follicles are epidermal invaginations; hair is keratin produced by these cells.
- Adnexal glands (apocrine and sebaceous) are present in the dermis for hair maintenance.
Glossary of Terms
- Alopecia: hair loss; Dermatitis: inflammation in the dermis; Hyperkeratosis: increased keratin thickness; Folliculitis: hair follicle inflammation; Spongiosis: fluid accumulation in the epidermis.
Diagnosing Skin Disease
- Clinical history should include age, sex, breed, pruritus, duration of lesions, and systemic health signs.
- Clinical examination focuses on lesion distribution and characteristics for presumptive diagnoses.
- Diagnostic samples can include skin scrapes, Sellotape strips, and cytology of biopsies.
- Skin biopsy advantages: broad diagnostic range but costly; histology can confirm multiple skin diseases. Examine only primary lesions for accurate diagnosis.
Environmental and Physical Diseases
- Solar cutaneous diseases relate to skin's susceptibility based on hair, keratin thickness, and pigmentation.
- Photosensitization: can be congenital, primary (chemical ingestion), or secondary (liver damage causing phylloerythrin buildup).
- Spring eczema is a solar-induced dermatitis unique to New Zealand, with mild manifestations in calves and severe in adults.
- Chronic sun damage can lead to skin neoplasia, such as squamous cell carcinomas and hemangiosarcomas.
Dermatological Conditions
- Acral lick dermatitis: chronic self-trauma in dogs resulting in epidermal hyperplasia; often behavioral.
- Feline psychogenic alopecia: excessive grooming leads to hair shaft breakage; often seen in anxious cats.
- Callus: hyperplastic epidermis due to pressure from hard surfaces; leads to secondary infections.
- Injection site reactions from vaccines can vary by species; nodular reactions in most species, vasculitis in some dog breeds.
- Skin fold dermatitis arises when skin surfaces rub together; moisture leads to bacterial infection, commonly in dogs and cattle.
- Temperature extremes: burns classified by degree (1st epidermis, 2nd epidermis and dermis, 3rd full thickness).### Burns and Frostbite
- Superficial dermal burns lead to blistering and significant exudation.
- Severe dermal damage causes coagulative necrosis, thrombosis, and infarction, inhibiting exudation.
- Secondary infections in devitalized dermis can be fatal.
- Frostbite is rare in New Zealand, primarily affecting extremities like dairy cow teats.
- Neonates and animals moved from warm climates are more susceptible to frostbite.
- Exposure to extreme cold causes sustained blood vessel contraction, leading to tissue hypoxia.
- Cats can develop 'cold agglutination disease' (cryofibrinogenemia), where cold temperatures cause blood agglutination and tissue damage.
- Symptoms resembling frostbite can occur without extreme cold due to abnormal plasma proteins.
Infectious Diseases
- Skin is constantly exposed to infectious agents; bacterial infections typically require predisposing factors.
- Viral and fungal infections can occur without prior skin disorders.
Bacterial Skin Disease
- Skin defenses include physical barriers (hair, keratin), chemical barriers (fatty acids, immunoglobulin), and a resident microbial barrier.
- Keratin serves as a vital physical barrier, providing a dry environment that inhibits bacterial colonization.
- Infection occurs when skin defenses are disrupted by friction, moisture, or altered epidermis maturation.
- Restoration of skin defenses is crucial for resolving bacterial infections.
- Staphylococcus pseudintermedius commonly causes bacterial skin infections in companion animals.
- Most strains are antibiotic-susceptible in New Zealand, making routine cultures less informative.
Superficial Bacterial Infections
- Confined to the epidermis, these infections include:
- Superficial pustular dermatitis: Overgrowth caused by impaired skin defenses, common in young animals. Not contagious and typically resolves as defenses are restored.
- Pyotraumatic dermatitis (hot-spot dermatitis): Caused by self-trauma and moisture, often associated with allergies.
- Dermatophilosis: Caused by Dermatophilus congolensis in chronically damp conditions. Treated by reducing moisture and restoring defenses.
- Exudative epidermatitis of pigs: Caused by Staphylococcus hyicus, resulting in greasy, malodorous exudation, particularly in young pigs.
- Fleece rot and equine pastern dermatitis: Result from moisture entrapment, leading to bacterial proliferation and skin damage.
- Interdigital dermatitis and foot rot: Caused by chronic moisture allowing infection by Fusobacterium necrophorum and other bacteria.
Deep Bacterial Infections
- Defined by bacteria and neutrophils within the dermis (pyoderma) and require more intensive treatment.
- Persistence of bacteria complicates resolution, necessitating prolonged antibiotics.
- Common examples include:
- Staphylococcal folliculitis and furunculosis: Often in dogs, sheep, and horses, commonly linked to pressure points or trauma.
- Infections of penetrating wounds: Common cat bite abscesses from contaminated puncture wounds.
- Mycobacterial infections: Nodular lesions observed in several species, including cutaneous leprosy in cats and dogs.
- Botryomycosis: Nodular bacterial infections, often from wound infections leading to yellow "sulphur granules."
Viral Skin Disease
- Pox viruses: Cause skin disease in various species, with zoonotic potential.
- Parapox viruses in New Zealand cause papular stomatitis in calves and contagious ecthyma in sheep and goats.
- Herpes viruses: Economically important in cattle and can cause various conditions, including mammillitis and coital exanthema.
- Papillomaviruses: Cause hyperplastic papillomas, typically self-limiting but can be persistent in some cases, particularly in young animals.
Fungal Skin Disease
- Sub-classified as cutaneous, subcutaneous, or systemic.
- Fungal infections involve keratinized layers of the epidermis, with potential inflammation in the dermis.### Ringworm (Dermatophytosis)
- Commonly referred to as ringworm, it's the most prevalent fungal skin disease in animals and humans.
- Young, immunosuppressed animals are most susceptible, especially in humid, overcrowded environments.
- Microsporum canis is the primary causative agent in cats and dogs, thriving particularly in long-haired breeds.
- Fungi invade keratin in hair shafts, leading to inflammation and epidermal hyperplasia.
- Hair shaft damage can cause breakage, and severe cases may lead to furunculosis.
- Typical lesions manifest as crusting and alopecia; fluorescence with Wood’s lamp can aid diagnosis, more common in cats.
- Fungal cultures are also diagnostic without requiring biopsies.
- Most animals develop immunity after infection, leading to spontaneous resolution.
- Infecting nails can lead to soft, discoloured nails that easily break.
- Trans-species infections of M. canis can occur in humans, though animals typically do not experience pruritus.
Malassezia Dermatitis
- Caused by the yeast Malassezia pachydermatis, mainly seen in dogs, particularly small breeds.
- Typically originating from ear canals, it proliferates due to impaired skin defenses, often from secondary atopy.
- Clinical signs include hyperpigmentation, lichenification, alopecia, and an unpleasant odour.
- Treatment revolves around addressing underlying conditions, with excessive keratin removal often being curative.
- West Highland White Terriers show congenital susceptibility, complicating treatment.
Cryptococcosis
- Caused by Cryptococcus neoformans, usually enters via the lungs.
- From the lungs, it predominantly infects the nasal cavity, skin, and reproductive organs.
- Common lesions are nodular, often found on the face, ears, and paws.
- Diagnosis is confirmed through cytology or histology.
- Surgical excision may be curative for isolated cutaneous lesions but may indicate potential systemic involvement.
- Notably affects cats, but all species can be infected; it's more serious in immunocompromised humans.
Demodicosis
- Primarily affects dogs, caused by Demodex mites which are host-specific and generally asymptomatic.
- Risk factors include age (common in dogs under one year) and certain breeds, such as pit bulls.
- Symptoms manifest as erythematous, alopecic, crusting areas mainly on the face and forelegs.
- Diagnosis is achieved through skin scraping, revealing large numbers of mites.
- Histological findings include follicle distention, pigmentation changes, and potential for secondary bacterial infection.
Sarcoptic Mange
- Caused by Sarcoptes scabiei, significantly affects pigs and dogs; transmitted through direct contact.
- Characterized as a hypersensitivity reaction, where even few mites trigger severe pruritus.
- Clinical lesions start on ears, elbows, and neck due to self-trauma; histologically shows hyperplasia and eosinophilic dermatitis.
- Treatment often leads to dramatic improvement and can serve as a confirmation of diagnosis.
Fleas
- Major parasites for cats and dogs, causing irritation and potentially anemia in young animals.
- Fleas predominantly trigger allergic skin disease, leading to significant discomfort.
Chorioptic Mites
- Affect cattle, horses, goats, and sheep, typically found on lower limbs and sensitive areas causing crusting and alopecia.
Immunity and Allergic Skin Disease
- Immune-mediated diseases are common in companion animals, rarely affecting food animals.
- Allergic skin diseases result from excess IgE production, with genetic predispositions playing a role.
- Environmental allergens lead to localized or systemic reactions, characterized by inflammation and self-trauma lesions.
Flea Allergy
- Flea saliva is the most common cause of allergy-related dermatitis in dogs and cats, affecting typical flea-occupied areas.
- Histological findings may include eosinophilic pustules, but fleas can be difficult to detect.
Atopy
- Atopy prevalence has increased with better flea control measures; environmental allergens are typically involved.
- Seasonal patterns are common, with pruritus mainly around the face and feet; predisposition to ear infections is notable.
- Genetic predisposition is significant, affecting up to 50% of animals with a family history of allergies.
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Description
This quiz explores the impact of frostbite and cold agglutination disease in animals, particularly focusing on dairy cows and other species. Learn about the effects of extreme cold on tissue health and the risk factors involved in these conditions. Understand how environmental changes affect animal health and management strategies.
