Skin Layers and Structure
What is the outermost layer of the skin?
Epidermis
Name one way the skin prevents infection.
Acts as a physical barrier; contains immune cells.
Contact dermatitis is what type of hypersensitivity reaction?
Type IV (delayed) hypersensitivity.
Impetigo lesions have what characteristic appearance?
Honey-colored crusts.
Acne vulgaris is caused by excess production of what?
Sebum from sebaceous glands.
What is the primary cell type in the epidermis that produces keratin?
Keratinocytes
Which layer of skin contains sweat glands, sebaceous glands, nerves, and hair follicles?
Dermis
What is the main cause of diaper dermatitis and how can it be prevented?
Prolonged exposure to moisture/irritants; frequent diaper changes.
Cellulitis involves which layers of the skin?
Dermis and subcutaneous tissue.
Psoriasis is what type of disorder, and what are its characteristic lesions?
Autoimmune; plaques with silvery scales.
The epidermis is avascular. What does that mean?
It has no blood vessels; nutrients diffuse from the dermis.
The skin helps regulate temperature through what two vascular mechanisms?
Vasoconstriction and vasodilation
What type of dermatitis occurs in skin folds from friction and moisture?
Intertrigo
What bacteria commonly cause folliculitis and furuncles?
Staphylococcus aureus (often MRSA).
Chronic venous insufficiency can lead to what dermatitis type?
Stasis dermatitis.
Which layer of the skin provides structural support and contains hair follicles, nerves, and glands?
Dermis
What vitamin does the skin produce with sunlight exposure?
Vitamin D
What are the six Ps of lichen planus?
Planar, pruritic, papule, plaque, purple, polygonal.
Tinea infections are caused by what organism type, and what is another name for them?
Fungi; dermatophytes (ringworm).
Which condition presents as a “Christmas tree” rash and is self-limiting?
Pityriasis rosea.
What are the main structural proteins in the dermis providing strength and elasticity?
Collagen and elastin
What are three general functions of the skin?
Barrier, temperature regulation, sensory/immune defense.
Atopic dermatitis (eczema) is what type of immune reaction, and what is its hallmark symptom?
Type I (IgE-mediated); intense pruritus.
Name the viral infection that causes small dome-shaped pearly papules.
Molluscum contagiosum (poxvirus).
Which two parasitic infections cause itching and require treatment of clothing and bedding?
Scabies and lice infestation.