Intro to Dermatology 2024 PDF

Johnson & Wales University Physician Assistant Program Dermatology Module Intro to Derm 2024 Mark Trott, MBA, MHP, PA-C Diplomate Fellow-SDPA [email protected] Agenda Session 1 Session 3 Intro to Dermato...

Johnson & Wales University Physician Assistant Program Dermatology Module Intro to Derm 2024 Mark Trott, MBA, MHP, PA-C Diplomate Fellow-SDPA [email protected] Agenda Session 1 Session 3 Intro to Dermatology Skin Based Disorders III Approach to the Dermatology Nevi and Skin Cancer Patient Skin Based Disorders IV Common Skin Lesions Session 4 Session 2 Hair and Nail Disorders Skin Based Disorders I Derm Diagnostic Procedures Topical Steroids Skills Lab Skin Based Disorders II Session 5 Derm Cases/Review Introduction to Dermatology Goals Introduce the specialty of Dermatology Establish a clinical understanding of the skin and its appendages Set the foundation for properly describing skin lesions and rashes Dermatology Clinically Diverse Specialty Medical Surgical Cosmetic Scope of Dermatology Skin Hair Nails Mucous Membranes  OB/GYN URGENT CARE EMERGENCY MEDICINE RHEUMATOLOGY Dermatology ALLERGY/IMMUNOLOGY/ENT ENDOCRINOLOGY PSYCHIATRY/BEHAVIORAL HEALTH SURGICAL SPECIALTIES Dermatologic Diagnoses Neoplasms Infections Benign Bacterial; Fungal Malignant Viral; Protozoal Inflammatory Disorders Other Papulosquamous Cutaneous Manifestations of Eczematous Systemic Disease Urticarias Psychogenic Erythemas Toxic Insults Autoimmune Trauma Connective Tissue Diseases Congenital and Developmental Blistering Disorders Disorders Who Evaluates and Manages Skin Disease? More than 60% of visits for skin disease are made to non- dermatologists “Probably Ringworm?” “Probably a Drug Rash?” “Probably Benign?” Dermatology Terminology Accurately describing skin lesions and rashes is arguably the most important skill in Dermatology Communication between Clinicians Accuracy of Differential Diagnosis Quicker Diagnosis Definitive Treatment  How would you describe this? “Rash on chest” 3 cm DDX for “grouped vesicles on a red base” Herpes Simplex Herpes Zoster- Shingles Allergic Contact Dermatitis  Functions of the Skin Protective Barrier Injury Repair Protection from trauma Wound Healing Keeps good things in and bad things out Circulation Immunologic Protection Hematologic/Lymphatic Infection; Toxins; Cancer Communication Autoimmunity Cellular/Humoral/Neurologic Thermoregulation Aesthetic Sweating Attract attention Vasodilation-Vasoconstriction Sexual signaling Structure of the Skin Epidermis Dermis Subcutaneous Layer Adnexal Structures Hair, Nails, Glands Epidermis What is the dominant cell type of the epidermis? A. Keratinocytes B. Melanocytes C. Langerhans Cells D. Merkel Cells Cells of the Epidermis Keratinocytes Produce Keratin Key structural protein-skin, hair, nails Produce Lipids Ceramides Free Fatty Acids Cholesterol Keratinocyte Journey Basal Layer Stratum Corneum Dividing stem cells produce immature keratinocytes Granular Layer Spinous and Granular Layer Spinous Layer Keratinocytes undergo squamous differentiation as they migrate upward Basal Layer Stratum Corneum Flattened anuclear keratinocytes Keratotic Lesions Keratosis A neoplasm arising from proliferating keratinocytes Types of Keratoses Benign Pre-cancerous Cancerous Clinical Features of Keratoses Rough or “keratotic” raised lesions Examples of Keratotic Lesions Seborrheic Keratosis Actinic Keratosis Squamous Cell Carcinoma Cells of the Epidermis Melanocytes Dendritic pigment producing cells located along the basal layer Examples of Melanocytic Lesions Melanocytic Nevus A benign mole Melanoma A serious malignancy Melanocytic Lesions Melanocytic Nevus Melanoma Melanocytes Melanin The dominant pigment that gives us our unique skin color Melanocytes transfer melanin into keratinocytes Once in the keratinocytes, melanin concentrates around the nucleus protecting it from UVR  Concentration of Melanocytes is consistent across all skin types! In Darker Skin In Lighter Skin Melanocytes Melanocytes have longer have shorter dendrites and dendrites and deposit more deposit less melanin melanin lower throughout the in the epidermis epidermis Fitzpatrick Skin Phototypes Type I Type II Type III Always Burns Usually Burns Sometimes Burns Never Tans Tans With Difficulty Tans Average Type IV Type V Type VI Rarely Burns Rarely Burns Never Burns Tans Easily Tans Very Easily Tans Quickly Fitzpatrick Skin Phototypes Clinical Application Predicting skin cancer risk Recognizing variable presentations of skin disease in different skin tones Choosing therapeutic or cosmetic modalities that enhance outcomes and limit adverse effects across all skin tones Cells of the Epidermis Langerhans Cells Dendritic macrophages that provide continuous immuno-surveillance for antigens in the epidermis Antigen presenting cells of the Epidermis Located mostly in the spinous layer Cells of the Epidermis Merkel Cells Touch receptors associated with nerve endings deep in the epidermis Under both neurologic and endocrine control Dermis Dermis Provides structural support for the skin Nurtures and communicates with the avascular epidermis Location of Skin Appendages Hair Follicle Sebaceous Glands Sweat Glands Dermis Rete Ridges Dermal-Epidermal Junction (DEJ) Specialized Basement Membrane Zone (BMZ) where the dermis interfaces with the epidermis Papillary Dermis Upper 20% Looser connective tissue Reticular Dermis Lower 80% Denser connective tissue Dermal Papillae Cells of the Dermis Fibroblasts Produce extracellular matrix (ECM) proteins that give the dermis its structural support Collagen and Elastin Ground Substance Adhesive Proteins “On-call” to assist with Maintaining ECM Wound Healing Tissue Fibrosis…scar formation Other Cells of the Dermis Dermal Dendritic Cells Mast Cells Antigen presenting cells of the Regulate skin inflammation and dermis immunity Leukocytes Plasma Cells Neutrophils Antibody secreting cells that help Eosinophils maintain the skin barrier, clear Lymphocytes cellular debris, repair tissue damage and prevent autoimmunity Wound Healing and Scars Tissue response to Dermal Injury Inflammatory Phase Begins immediately Regulated by pro-inflammatory and anti-inflammatory cytokines Proliferative Phase Ongoing throughout the healing process Macrophages release growth factors that regulate Fibroblast activity Remodeling Phase Starts at week 3 and lasts 12 months Reorganization of collagen and wound contraction resulting in a Mature scar Scars Types of Scars Normal Scars Atrophic Scars Hypertrophic Scars Keloidal Scars Normal Scars Normal Scars Heal Relatively Flat Discolored Asymptomatic Atrophic Scars Atrophic Scars Depressed Scars Secondary to dermal or subcutaneous injury Examples “Icepick scars” associated with acne Steroid Atrophy Hypertrophic Scars Hypertrophic Scars Thick scars that respect the boundaries of the original injury Fibroblasts produce excess ECM and up to 3X more collagen than normal scars Can be painful or itchy Often flatten over time naturally Respond better to treatment than Keloids Keloidal Scars Keloids Thick scars that do not respect the boundaries of the original injury Abnormal Fibroblast activity results in up to 20 X more collagen than normal scars Often delayed in onset Can be painful or itchy Respond poorly to treatment Scars DX Clinical Normal Atrophic Hypertrophic Keloidal Scars RX Occlusive Dressings Silicone gel pads Compression Therapy Button Compression; Pressure Earrings Steroids Intralesional Triamcinolone 10-40mg/ml q 4-6 wks 2nd Line Excision Radiation Laser Intralesional Fluorouracil Subcutaneous Layer Fatty Layer- “Panniculus” Simple structure Adipocytes Fibrous Septae Functions Physical protection Binds skin to underlying structures Thermoregulation Energy reserve Fat Cells Septae Disorders of the Subcutaneous Layer Panniculitis Refers to a group of disorders whose hallmark is inflammation of subcutaneous tissue Septal Lobular Mixed Erythema Nodosum Most common Panniculitis in childhood Skin Appendages Pilosebaceous Unit Sebaceous Glands Arrector pili muscle Hair and Hair Follicle Sweat Glands Nails  Sebaceous Glands Follicular Ostium Sebaceous Glands Oil producing glands Secrete sebum into the hair follicle lubricating the skin and hair Generalized Distribution But not on palms and soles Rich with Androgen Receptors Androgens influence sebaceous gland size and production of sebum Arrector Pili Muscle Attaches the hair follicle to the papillary dermis Contracts in response to cold or fear slightly raising the skin making the hair stand erect “Goose bumps” The Hair Follicle Follicular Ostium Follicular Infundibulum Upper portion of follicle From the sebaceous gland to the follicular ostium Lined with epidermis The Hair Follicle Isthmus Mid portion of follicle From sebaceous gland to pili muscle Location of Bulge region Source of Stem Cells Migrate upward and differentiate to support the sebaceous glands and the epidermis Bulge Migrate downward to support the hair matrix The Hair Follicle Bulb Lower portion of the follicle Matrix Stem cells differentiate to form the growing hair Melanocytes here give hair its color Dermal Papilla Provides blood, oxygen and nutrients to the matrix Rich with Androgen Receptors Androgens regulate hair follicle activity and hair growth Hair Growth Cycle Anagen Phase Catagen Phase Telogen Phase Period of active growth Involutional stage Resting Phase 90% of scalp hairs 1% of scalp hairs