Lecture 29

What is Ichthyosis characterized by?

Generalized scaling due to defects in stratum corneum formation, with clinical signs including lamellar hyperkeratosis, lichenification, and crusting.

What causes Epidermolysis Bullosa and what are the clinical signs ?

Mutations in structural proteins such as keratins, integrins, and collagens. Clinical signs include blistering and ulceration of skin and mucous membrane

What is the clinical sign of Congenital Hypotrichosis?

Absence of hair follicles and/or abnormal follicular development, leading to less hair.

What type of diseases are caused by UV exposure?

Actinic Diseases.

What is Photosensitisation Dermatitis?

A condition where photodynamic substances in the skin are activated by UV-A or visible light.

What are the three types of Photosensitisation Dermatitis?

Type I is exogenous agents, Type II involves aberrant heme pigment synthesis, Type III is due to abnormal phylloerythrin buildup from a damaged liver

What is facial eczema

A type of Photosensitisation Dermatitis that affects the face of sheep, commonly caused by the accumulation of photodynamic substances in the skin, leading to inflammation and irritation.

What virus causes contagious ecthyma or scabby mouth and its clinical sign?

A zoonotic parapox virus which causes ballooning degeneration.

Which types of viruses cause the vesicular diseases such as FMD, vesicular stomatitis, vesicular exanthema and swine vesicular disease

These are caused by epitheliotropic viruses

Which bacteria cause Greasy Pig Disease and what type of disease is it

Staphylococcus hyicus. It is an exudative epidermatitis

What is Malassezia Dermatitis?

An opportunistic secondary fungal infection often associated with excessive sebum production, moisture accumulation, and barrier disruption.

What causes dermatophilosis and what is it characterised by histologically

Caused by Dermatophilus congolensis, it is characterized histologically by branching filaments that form parallel rows of coccoid zoospores

What causes feline leprosy

Mycobacterium lepraemurium

What is dermatophytosis

A highly contagious, zoonotic, superficial fungal infection caused by genera including Epidermophyton, Microsporum and Trichophyton

What is the primary cause of Sarcoptic Mange?

Infestation by Sarcoptes scabiei, which burrows and tunnels into the stratum corneum.

What clinical signs are associated with sarcoptic mange

alopecia, thickened crusts, erythema, pruritic lesions, lichenification

What causes demodectic mange and what are the clinical signs

Demodectic mange is caused by an overpopulation of Demodex mites, leading to clinical signs such as alopecia, erythema, hyperpigmentation and comedones

What are typical clinical signs of endocrine disorders in the skin?

Bilaterally symmetrical alopecia, hyperpigmentation, secondary pyoderma, and scaling.

Which condition is characterized by hypersensitivity Type I with symptoms like pruritis and lesions on forepaws?

Atopic Dermatitis.

What is urticaria

A hypersensitivity dermatosis which is Type I and is characterised by wheals which are focal areas of oedema

What clinical signs would you see with flea allergy dermatitis

Alopecia and erythema in the caudal region. Cats can see erythmeatous plaques in the abdomen as well

What is the pathogenesis of Pemphigus Complex?

Autoantibodies are made against the desmoglein proteins of the keratinocytes → causes seperation and individualisation of the keratinocytes (=acantholytic cells) → disruption of the keratinocyte layer

What lesions would you see in pemphigus complex disease

Vesicles, pustules, and erosions on the skin, often involving the oral mucosa and other areas. such as the ear or generalised areas in horses

What are clinical signs of Lupus Erythematosus?

Pigmentation of nasal area, crusting, pustule formation, and potentially systemic disease.

What is lupus erythematosus

An autoimmune disease where antibodies are created against nuclear antigens (the nucleus) → immune response which can cause organ damage

What characterizes Equine Pastern Dermatitis or Greasy Heel?

A cutaneous syndrome influenced by genetics, long hair coats, moisture, and trauma, showing lesions around the hindlimbs and particularly the hoof and pastern region

What are the 3 presentations of Greasy heel

• Mild form = mud fever → see inflammation and erythema and alopecia in the pastern region

• Exudative form = greasy heel → see exudative discharge

• Chronic proliferative form = grapes → proliferative lesions which look like grapes due to exuberant granulation tissue

What is feline eosinophilic granuloma complex

A group of skin lesions in cats, characterized by eosinophilic inflammation, often manifesting as ulcers, plaques, or granulomas

What is seen with Hypothyroidism?

Can see myxedema.

What is seen with Hyperadrenocorticism?

Can see lots of comedones and can be endogenous or exogenous.

What is seen with Gonadal hormone imbalance?

Alopecia starts at the caudal end.

What is seen with Alopecia X?

Pathogenesis unclear but can see lots of alopecia and thin skin.

What is seen with Equine pituitary adenoma?

Causes hypertrichosis = hair retention.