Skin Injuries and Lesions Overview

Questions and Answers

What are the characteristics of hair loss known as alopecia?

Alopecia refers to the loss of hair, which can vary in severity and can be influenced by factors such as hormonal changes or disease.

Define hyperpigmentation and provide an example of a condition that may cause it.

Hyperpigmentation is the increased production of melanin from existing melanocytes, commonly seen in conditions like melanosis.

What is a comedo and in which condition is it notably observed in dogs?

A comedo is a dilated hair follicle filled with cornified cells and sebaceous material, notably seen in dogs with hyperadrenocorticism (Cushing's syndrome).

Explain the term 'lichenification' as it relates to skin conditions.

Lichenification refers to the thickening and hardening of the skin with exaggeration of superficial markings, often due to chronic irritation. Signup and view all the answers

What does the term 'effluvium' describe in terms of hair?

Effluvium describes excessive shedding of hair, which can be triggered by various stressors or health conditions. Signup and view all the answers

Differentiate between hypertrichosis and hypotrichosis.

Hypertrichosis is the condition of having more hair than normal, while hypotrichosis refers to having less hair than normal. Signup and view all the answers

What is leukoderma and what causes it?

Leukoderma is a condition characterized by decreased pigmentation of the skin, often due to a lack of melanocytes or their failure to produce melanin. Signup and view all the answers

Describe the appearance and significance of an epidermal collarette in skin lesions.

An epidermal collarette appears as a circular rim of keratin flakes following the loss of the 'roof' of a vesicle or pustule, often indicating previous inflammation or infection. Signup and view all the answers

What are primary lesions and why are they significant in dermatological diagnosis?

Primary lesions are direct results of the underlying disease process and arise from the same organ. They are significant diagnostically because they provide crucial insights into the specific condition affecting the skin. Signup and view all the answers

Differentiate between a macule and a papule in terms of size and characteristics.

A macule is an area of altered skin color up to 1 cm, while a papule is a small, round solid elevation of the skin that is also 1 cm in size. The key difference lies in the elevation; a macule is flat while a papule is raised. Signup and view all the answers

What defines a vesicle, and how does it differ from a bulla?

A vesicle is a well-circumscribed elevation of the epidermis less than 1 cm in diameter filled with clear fluid. In contrast, a bulla is larger than 1 cm and is also filled with fluid. Signup and view all the answers

What is a tumor in the context of skin lesions, and how does it differ from a cyst?

A tumor is a large mass that implies neoplasia and can involve any structure of the skin or subcutis, whereas a cyst is an epithelial lined cavity containing fluid or solid material. Tumors generally indicate abnormal growth while cysts are typically benign. Signup and view all the answers

Explain the term 'wheal' and provide a common cause for its appearance.

A wheal is a smooth, sharply circumscribed elevation of skin due to dermal edema, often seen in allergic reactions or hypersensitivity disorders. It commonly occurs in conditions affecting horses and less frequently in dogs. Signup and view all the answers

How are secondary lesions different from primary lesions in terms of their development?

Secondary lesions evolve from primary lesions and are caused by processes such as self-trauma or altered keratinization. They are considered less important diagnostically compared to primary lesions. Signup and view all the answers

What is the role of pustules in skin conditions, and how are they defined?

Pustules are small, circumscribed elevations of the epidermis that are filled with pus. They typically indicate an infection or inflammatory process in the skin. Signup and view all the answers

Define an abscess and its significance in diagnosing skin infections.

An abscess is a small, circumscribed accumulation of pus within the epidermis or within a follicle. Its presence is significant as it often indicates an underlying infection that requires treatment. Signup and view all the answers

Study Notes

Factors Causing Skin Injury

External (exogenous) factors include environmental influences.
Internal (endogenous) factors arise from within the body.

Types of Skin Lesions

Primary lesions: Direct results of disease, crucial for diagnosis.
Secondary lesions: Evolve from primary lesions, usually less diagnostically significant.

Primary Skin Lesions

Macule: Discolored area, ≤ 1 cm; example: lentigo, a benign hyperpigmentation.
Papule: Small, round, solid elevation, ≤ 1 cm in size.
Plaque: Larger, flat-topped solid elevation of the skin.
Nodule: Hard elevation, ≥ 1 cm, extends into deeper skin layers.
Vesicle: Circumscribed elevation of < 1 cm filled with clear fluid.
Bulla: Larger vesicle (> 1 cm) containing fluid within the epidermis.
Tumor: Large mass implicating neoplasia, affecting skin or subcutis.
Cyst: Epithelial-lined cavity with fluid or solid material.
Pustule: Small, pus-filled elevation of the epidermis.
Abscess: Accumulation of pus within epidermis or hair follicle.
Wheal: Smooth, well-defined elevation from dermal edema, commonly seen in allergic reactions.

Secondary Skin Lesions

Scale: Accumulation of flakes or dandruff on the skin surface.
Crust: Dried exudate, blood, or serum accumulation.
Comedo: Dilated hair follicle filled with cornified cells; often seen in conditions like hyperadrenocorticism.

Hair Abnormalities

Alopecia: Loss of hair.
Hypotrichosis: Less hair than normal.
Atrichia: Absence of hair due to failure of development.
Effluvium/defluxion: Excessive shedding.
Hypertrichosis (hirsutism): More hair than usual; can be due to endocrine disorders.

Epidermal Pigmentation Alterations

Hyperpigmentation: Increased melanin production, often due to inflammation or genetics.
Hypopigmentation: Reduced melanin, can be congenital or due to melanocyte dysfunction.
Pigmentation incontinence: Loss of melanin from the basal epidermis.

Secondary Lesion Characteristics

Epidermal collarette: Circular rim of keratin flakes after vesicle/pustule loss.
Ulcer: Break in the epidermis, exposing underlying dermis.
Excoriation: Erosions or ulcers from scratching or trauma.
Scar: Fibrous tissue replacing damaged skin.
Fissure: Linear cracks in thickened, inelastic skin.
Lichenification: Thickening and hardening of skin with visible superficial markings.

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Description

Explore the various factors causing skin injury and the types of skin lesions. This quiz provides insights into primary and secondary lesions, including their characteristics and importance in diagnosis. Test your knowledge of skin health and related terminologies.