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Questions and Answers
What is the primary function of the skin?
Which type of immune cells are found in the epidermis?
What is a macule?
Which of the following skin lesions is more than 5 mm in size?
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What is a common term for both a vesicle and a bulla?
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What is a common characteristic of acute eczematous dermatitis lesions?
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Which of the following conditions can trigger erythema multiforme?
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What type of lymphocytes mediate the epithelial injury in erythema multiforme?
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What is a distinguishing feature of chronic eczematous dermatitis lesions?
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Which complication may arise from drug-induced erythema multiforme?
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What is the primary mediating mechanism in urticaria?
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What characterizes wheals in acute urticaria?
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Which of the following is NOT a typical treatment for urticaria?
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What distinguishes angioedema from wheals in urticaria?
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Which finding is commonly seen in the pathology of urticaria?
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Which type of eczema is caused by delayed hypersensitivity reactions?
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In chronic eczema, what characterizes the lesions?
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What age group is primarily affected by urticaria?
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What characterizes a wheal in skin lesions?
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Which of the following is NOT a requirement for diagnosing skin diseases?
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What does the term acanthosis refer to in pathology?
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Which condition is characterized by intercellular edema of the epidermis?
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What type of skin diseases persist for days to several weeks and are characterized by inflammation and edema?
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Which term describes the abnormal, premature keratinization occurring within cells beneath the stratum granulosum?
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Which skin lesion results from a traumatic injury breaking the epidermis?
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What is the primary characteristic of lichenification in skin lesions?
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Study Notes
Skin
- The skin is the largest organ in the body, composed of the epidermis and dermis.
- The skin is a critical part of the immune system.
- The dermis contains T lymphocytes, memory T cells, regulatory T cells, and B cells.
- The epidermis contains intraepithelial lymphocytes, including γ/δ T cells.
Skin Diseases Diagnosis
- Skin diseases are diagnosed based on clinical history, gross appearance, distribution of lesions, and pathology findings.
Skin Lesions
- Macule: A flat, circumscribed lesion with discoloration, ≤5 mm in diameter.
- Patch: A flat, circumscribed lesion with discoloration, > 5 mm in size.
- Papule: A dome-shaped or flat-topped, elevated lesion, ≤ 5 mm in diameter.
- Nodule: A dome-shaped, elevated lesion, > 5 mm in size.
- Plaque: An elevated, flat-topped lesion, > 5 mm in diameter.
- Pustule: A discrete, pus-filled, raised lesion.
- Vesicle: A fluid-filled, raised lesion ≤ 5 mm in diameter.
- Bulla: A fluid-filled, raised lesion >5 mm in diameter.
- Wheal: An itchy, transient, elevated lesion caused by dermal edema, with variable erythema.
- Scale: A dry, horny, plate-like excrescence.
- Excoriation: A traumatic lesion breaking the epidermis, often due to scratching.
- Lichenification: Thickened, rough skin, often resulting from repeated rubbing.
Pathology Terms
- Hyperkeratosis: Thickening of the stratum corneum, often associated with abnormal keratinization.
- Parakeratosis: Retention of nuclei in the stratum corneum.
- Acanthosis: Diffuse epidermal hyperplasia.
- Dyskeratosis: Abnormal, premature keratinization within cells below the stratum granulosum.
- Acantholysis: Loss of intercellular connections resulting in loss of cohesion between keratinocytes.
- Spongiosis: Intercellular edema of the epidermis.
- Papillomatosis: Surface elevation caused by hyperplasia and enlargement of dermal papillae.
- Lentiginous: Linear melanocyte proliferation within the epidermal basal cell layer.
Skin Inflammatory Diseases
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Acute Inflammatory Skin Diseases: Last for days to several weeks.
- Characterized by inflammation and edema.
- May transition to chronic phases.
- Chronic Inflammatory Skin Diseases: Last for weeks to months.
- Infectious Dermatosis: Skin infections caused by viruses, bacteria, fungi, or parasites.
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Blistering (bullous) disorders:
- Characterized by blisters.
- Can be caused by autoimmune diseases or infections.
Acute Inflammatory Skin Diseases
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Urticaria (Hives):
- Most common in individuals between 20 and 40 years old.
- Mediated by mast cell degranulation.
- Can be caused by allergens, medications, or direct effects on mast cells.
- Approximately 75% of cases are idiopathic.
- Pathogenesis: Stimuli trigger mast cell to release histamine and other proinflammatory mediators leading to vasodilation and increased permeability of venules.
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Acute Eczematous Dermatitis:
- Characterized by rash, pruritus, and xerosis.
- Types: Allergic contact dermatitis (delayed hypersensitivity), Atopic dermatitis (genetic predisposition), Drug-related, Photoeczematous dermatitis, Primary irritant dermatitis.
Chronic Inflammatory Skin Diseases
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Psoriasis:
- Chronic inflammatory skin disease characterized by well-defined, scaly, erythematous plaques.
- Pathogenesis: Immune dysregulation leading to abnormal keratinocyte proliferation and inflammation.
- Pathology: Hyperkeratosis, parakeratosis, acanthosis, and neutrophilic infiltrate in the epidermis.
Erythema Multiforme
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Erythema Multiforme:
- Acute, self-limited hypersensitivity reaction.
- Typically triggered by infections, medications, or autoimmune diseases.
- Pathogenesis: CD8+ cytotoxic T lymphocytes attack epithelial cells, resulting in target lesions.
- Pathology: Interface dermatitis leads to epidermal injury and liquefactive necrosis.
- Stevens-Johnson syndrome: Severe form of erythema multiforme.
- Toxic Epidermal Necrolysis: Life-threatening form of erythema multiforme, characterized by widespread epidermal sloughing.
Urticaria (Hives)
- Pathology: Mild superficial dermal edema, dilatation of small blood vessels, mild perivascular lymphocytic infiltrates.
- Treatment: Antihistamines, oral corticosteroids (for angioedema).
Acute Eczematous Dermatitis
- Pathology: Acute lesions display spongiosis, dermal edema, and lymphocytic infiltrates. Chronic lesions show hyperkeratosis, acanthosis, and mild spongiosis.
Erythema Multiforme
- Pathology: Interface dermatitis, liquefactive necrosis, and dyskeratosis.
- Treatment: Identifying and removing the trigger, supportive care, and corticosteroids.
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Description
Test your knowledge on the skin's anatomy, its role in the immune system, and the various types of skin lesions. This quiz covers essential terminologies and diagnostic methods related to skin diseases. Perfect for students of dermatology and health sciences!
