Skin Lesions and Their Etiology

Skin Lesions

• Lesion: An abnormality in tissue, caused by damage or disease.
• Rash: A widespread eruption of lesions.
• Vesicle: A small elevated lesion filled with clear fluid (e.g., chickenpox, shingles).
• Bulla: A larger vesicle (greater than 0.5 cm), like a blister.
• Macule: A flat, discolored area of skin, not altering thickness or texture (e.g., freckles).
• Papule: A raised, solid, non-fluid-filled lesion, less than 0.5 cm (e.g., warts).
• Pustule: A raised lesion containing pus (e.g., acne, chickenpox).
• Cyst: A closed, fluid-filled sac deeper in the skin, often painless unless infected.
• Maculopapular Rash: Small, raised papules alongside or on top of macules (e.g., measles).
• Purpura: A rash of large purple spots due to bleeding in skin layers, does not blanch when pressed.
• Ulcer: A sore from destroyed skin layers, often due to secondary infection.

Etiological Agents and Transmission

• Chickenpox: Varicella zoster; respiratory droplets or direct contact.
• Shingles: Herpes zoster; reactivation of a latent virus.
• Smallpox: Variola; respiratory droplets or contact with infected fluids.
• HSV-1: Herpes simplex virus type 1; saliva or direct contact.
• HSV-2: Herpes simplex virus type 2; sexually transmitted.
• Rubeola (Measles): Measles virus; respiratory droplets.
• Rubella (German Measles): Rubella virus; respiratory droplets.
• Warts: Human papillomavirus (HPV); direct contact or contaminated surfaces.

Latent Persistent Infection

• Latent persistent infection: A dormant infection that can reactivate later.

Variola Major vs. Variola Minor

• Variola major: Severe smallpox, 30% mortality, deep scars.
• Variola minor: Less severe smallpox, 1% mortality.

HSV-1 vs. HSV-2

• HSV-1: Spread through saliva or direct contact.
• HSV-2: Spread through sexual contact.

Types of Warts

• Plantar warts: Warts on the feet.
• Seed warts: Warts on hands and toes.
• Flat warts: Warts on the genital region.

Acne Bacteria

• Acne: Caused by Cutibacterium acnes.

Skin Infections by Staph Aureus

• Impetigo: Superficial pus-filled vesicles.
• Erysipelas: Spread to surrounding skin, upper dermis and lymph nodes.
• Cellulitis: Infection spreads to lower dermis and subcutaneous tissue.
• Folliculitis: Red, pus-filled hair follicles.

Eye and Skin Diseases

• Conjunctivitis: Inflammation of the conjunctiva ("pink eye").
• Keratitis: Severe inflammation of the cornea.
• Viral Conjunctivitis: Predominantly caused by adenoviruses.
• Bacterial Keratitis: Primarily caused by Pseudomonas aeruginosa and Staphylococcus aureus.
• Bacterial Keratitis Risk Factors: Eye injury, contact lens use.

Explore the world of skin lesions and their various types, including rashes, vesicles, and ulcers. This quiz also covers the etiological agents associated with these skin conditions such as chickenpox. Test your knowledge on how these lesions manifest and what they signify in dermatology.