05 - PA 614 2023 Dermatology Basic Lesions Overcash.pptx

Introduction to Dermatology PA 614 : Fundamentals of Clinical Medicine (FCM) 2023 Michael Overcash, MPAS, PA-C, DSDPA Clinical Faculty, Medical Univ. of SC Skin: Functions • The Largest Organ • Protective: – Physical and chemical injury – Sunlight – Microorganisms (Infection) • – Loss of fluid...

Introduction to Dermatology PA 614 : Fundamentals of Clinical Medicine (FCM) 2023 Michael Overcash, MPAS, PA-C, DSDPA Clinical Faculty, Medical Univ. of SC Skin: Functions • The Largest Organ • Protective: – Physical and chemical injury – Sunlight – Microorganisms (Infection) • – Loss of fluids (dehydration) Regulation of body temperature • Sensory: Touch, Temperature, • Pain Synthesis of Vitamin D Skin: Structure • 1. Epidermis – Superficial, thinner • Avascular • Basement Membrane Zone: – Interface betw. Epidermis and Dermis: • 2. Dermis – Deeper, thicker connective tissue – Nerves and blood vessels • 3. Subcutaneous (SQ) Fat – “hypodermis” Layer 1: Epidermis- Key Players • • • • • • Composed of Stratified Keratinized Epithelium 4 cell types: 1. Keratinocytes: Produce keratin- a protective fibrous protein 2. Melanocytes: Produce pigment melanin 3. Langerhans cells: macrophages: immune function 4. Merkel cells: sensory Epidermis: Keratinocyt es Epidermis: melanocyt es Melanin is produced by melanocytes. All humans have about the same number of them. Fitzpatrick Scale [1-6]: relates to sun resistance, skin cancer, and tanning vs burning. Americans are a diverse mix of color and genetics: genomic analysis found that on an average the African American genome was 73.2 percent Africa n, 24 percent Europea n and 0.8 percent Native American. (23 and Me: 160,000 Basement membrane zone: Located in between Epidermis and Dermis Basement membrane zone: Located in between Epidermis and Dermis Basement Membrane : A thin layer of basal cells joining epidermis to dermis A selective filter for molecules moving between the 2 layers Site of bulla formation when the 2 layers become separated 2. The Dermis: Layer 2 • Connective tissue layer, mostly collagen • Contains nerves and blood vessels • Permanent: scarring occurs here, also tattooing 3. Hypodermis: Layer 3 • AKA Subcutaneous Fat (hypodermis) - loose, connective tissue, fat • Insulation • Contains: – sweat glands – base of hair follicles – Sense organs for • touch, pressure, temp Diagnosis of Skin Disease The challenge: 3,000 rashes and 500 tumors; one disorder can have numerous presentations, evolving in different stages. The Solution: Have an approach: – History – Distribution – Primary Lesion – Differential Diagnosis – Tests Coming up next: Describing a Rash: Primary Lesions • Primary – Macule – Flat, non-palpable lesion <1cm – Patch – Flat, non-palpable lesion >1cm – Papule – Raised lesion >0.5 cm – Plaque – A plateau-like lesion >0.5 cm – Vesicle – <0.5cm elevated lesion containing fluid – Bulla – >0.5cm elevated lesion containing fluid – Pustule – Elevated lesion containing pus – Wheal – Transient, elevated, edematous lesion often with clearing in center – Maculopapular – Some flat, some raised Coming up next: Describing a Rash: Secondary Changes • Secondary changes – Lichenification - Thickened skin with distinct borders – Crusted - Hard and rough surface caused by dried sebum, exudate, blood, or necrotic tissue – Scaly - Heaped up horny epithelium, flaky – Macerated - Increase in water content, soggy – Fissure - Thin, linear erosion or ulcer – Atrophy - Loss of skin or tissue, thinning, shiny – Excoriated - Shallow hemorrhagic excavation, linear or punctate, from scratching – Erosion - Partial break in epidermis – Ulcer - Full thickness loss of the epidermis Macule/ Patch -Flat, Not palpable Example of macules: Post-Inflammatory hyper/hypo- pigmentation Hyperpigmentation Hypopigmentation Papule/ Plaque -Papule: -elevated -up to 0.5 cm diameter -”Plaque” – Palpable/elevated May form when papules become confluent May have scale or crust Think psoriasis > 0.5 cm Vesicle • Fluid filled blister, raised, <5mm, superficial, well defined. (Grouped, linear, annular) • Larger than 5 mm is called ? K. Blair BULLA/BULLAE Wheals (Urticaria, Hives) • Transient elevated pink plaque • Gone in <24 hours K. Blair Scale • Excess accumulation of stratum corneum, flaky. K. Blair Crust • Dried exudate of fluids and cellular debris. Yellow (serous) or red (hemorrhagic) Erosion • • • • Loss of epidermis only (not dermis or BM) May ooze transudate not below epidermal-dermal junction. Heal without scarring. Ulcer • Erosion that extends into dermis • Scarring Fissur e • Crack in skin or ulcer in mucous membrane. K. Blair Atrophy • Thinning of skin, fat, muscle. Shiny, delicate, wrinkled, or depression. K. Blair Scar • After dermis destruction. May be erythematous, hypo/hyperpigmented, or destroy hair follicles. K. Blair ainhum Excoriations Comedones Open Comedone(s) Milia and miliaria <- Milia around the eyes are commonly caused by early sun damage Miliaria Crystallina Cyst • Raised pouch filled with liquid, solid, semisolid. Can be removed. https://youtu.be/4RoAatou_PE K. Blair • Petechiae • Purpura Burrow Lichenifica tion • Thickening characterized by accentuated skin folds. (elephant like skin). Telangiectasia Hyperkeratosis • Hypertrophy of horny (granular & spinous) layers. (Extensive callous) Quick quiz: name these lesions: Quick quiz: name these lesions: Quick quiz: name these lesions: