Viral Skin Infections Quiz

Viral infections of the skin can occur when the skin barrier is compromised, allowing viruses to enter.

Papillomaviruses are a group of viruses that cause skin growths called papillomas. They are epitheliotropic, meaning they infect epithelial cells, which are the cells that line surfaces, including skin.

Poxviruses cause skin lesions that progress through different stages: erythema (redness), papules (raised bumps), vesicles (fluid-filled blisters), pustules (pus-filled blisters), ulceration, and crust formation. The healing process often leaves scars.

Papillomas are neoplastic lesions, meaning they involve abnormal cell growth. They are caused by papillomaviruses and can be flat, raised, crusty, fissured, or horny.

Poxvirus infections are proliferative, meaning they involve rapid cell growth. The lesions are characterized by epidermal swelling, vacuolation (formation of spaces within cells), and multiloculated vesicles (blisters with many compartments).

A distinctive characteristic of poxvirus infection where cells swell up and develop tiny cavities within them.

Small, dense structures found inside infected cells that contain viral DNA or RNA.

A type of skin infection caused by poxviruses, often characterized by the progression of lesions through different stages: vesicles (fluid-filled blisters), pustules (pus-filled blisters), and crusts.

A thickening of the outermost layer of skin (epidermis) due to increased cell proliferation. Often seen in poxvirus infections.

A characteristic feature of contagious ecthyma, where the epidermis shows a spongy appearance with spaces between cells.

A skin infection, also known as contagious pustular dermatitis, caused by the Orf virus.

A type of abnormal cell growth characterized by an increase in the thickness of the epidermis.

Small, round structures that are found inside infected cells and contain viral proteins. These inclusions are often brightly colored when viewed under a microscope.

Refers to the remarkable resistance of intact skin to bacterial invasion due to factors like dryness, constant shedding of skin cells, and the presence of normal flora.

When the skin barrier is damaged, bacteria from the transient or resident flora on the skin can become pathogenic, causing infections.

Persistent moisture on the skin, leading to softening and breakdown of the outermost layer (stratum corneum) and loss of the protective lipid coat, increases bacterial colonization and infection.

Conditions or alterations that disrupt the normal process of skin cell development and shedding can increase bacterial susceptibility.

Physical damage to the skin, such as irritation from parasites, excessive rubbing, or trauma, can create entry points for bacteria.

Pyoderma is a general term for bacterial infections of the skin, ranging from superficial to deep.

Superficial pyoderma affects only the epidermis, often heals without scarring, and doesn't usually cause systemic illness.

Deep pyoderma involves the dermis and sometimes the subcutaneous layer, often scars, can be chronic, and may affect the lymph nodes and overall health.

Superficial mycoses are fungal infections that mainly affect the outermost layers of the skin, such as the stratum corneum, hair follicles, and hair shafts.

A characteristic feature of superficial mycoses is the circular patch of alopecia with expanding edges and central healing, creating a ring-like appearance.

Dermatophytosis, also known as ringworm, affects the keratinized layers of the skin, hair, and nails, causing inflammation.

Microsporum and Trichophyton are the common dermatophyte genera seen in young and immunocompromised animals. The infection spreads through direct contact, infected animals, or contaminated objects.

Dermatophytosis can manifest as circular patches of scaling and alopecia, sometimes progressing to papules, pustules, furunculosis, and crusting.

Dermatophytosis can affect various body parts, but one common manifestation is focal alopecia, erythema, and scaling on the canine pinna.

Dermatophytosis in cattle is characterized by multifocal alopecia with scaling and crusting, often observed on the head.

Dermatophytosis can affect humans. Exposure to infected animals, even if asymptomatic, increases the risk of contracting the infection.

A bacterial skin infection in dogs characterized by pustules and yellow crusty sores. It is often triggered by moisture, dirt, abrasions, parasites, or poor nutrition.

A superficial exudative dermatitis in ruminants, primarily observed in hot and humid environments.

A bacterial disease that causes a characteristic skin lesion in pigs with a rhomboid or diamond shape. It's a result of infection with Erysipelothrix rhusiopathiae.

A condition where the skin is severely irritated and the animal scratches excessively, leading to wounds and secondary bacterial infections. Symptoms include hair loss, scratches, and oozing sores.

A common bacterial skin infection in cats caused by bacteria colonizing hair follicles. It manifests as small blackheads or pustules, particularly on the chin.

A bacterial disease often caused by Salmonella or other bacteria that produce endotoxins. This can lead to blood clots in the veins of the extremities, causing tissue death.

A type of fungal infection that affects only the outer, non-living layers of skin.

A fungal infection of the skin caused by Microsporum spp. and Trichophyton spp. It primarily affects the non-living, outermost layer of skin.

Sporotrichosis is a subcutaneous infection caused by the fungus Sporothrix schenkii, typically entering through skin wounds. It causes nodules that often ulcerate, discharging a thick, red-brown exudate. Healing is slow.

Microscopically, Sporotrichosis is characterized by intense pyogranulomatous dermatitis with numerous cigar-shaped or oval budding yeast-like organisms within macrophages. These organisms are typically pink-stained and can be found intracellularly, extracellularly, or in microabscesses.

Deep mycoses are fungal infections caused by saprophytic fungi that primarily enter the body through inhalation or skin penetration. Examples include Cryptococcosis and systemic Sporotrichosis. They manifest as nodules, ulcers, fistulas, and abscesses.

Histologically, Deep Mycoses show granulomatous or pyogranulomatous dermatitis and can involve subcutaneous fat (panniculitis). These changes often accompany systemic fungal disease.

Subcutaneous mycoses are caused by saprophytic fungi that gain entry into the body through penetrating skin wounds. These infections primarily involve the subcutaneous tissues.