Dermatology Past Paper 2024 - PA2025
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Uploaded by SuppleEucalyptus8621
UNM PA Program
2024
Dr. Aimee Smidt
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Summary
This document contains lecture notes on dermatology, focusing on nails, hair, warts, and corns. It includes questions about hair follicle cycles, different types of hair loss, nail disorders, and various case studies. The provided text section seems more like a set of lecture slides than a formal past paper.
Full Transcript
Module 8: Nails, Hair, Warts and Corns Dr. Aimee Smidt Hair Disorders Androgenic alopecia in men and women Telogen effluvium Alopecia areata Some Basic Science about Hair Follicles The follicle is the embryologically derived structure that produces the hair shaft The hair sh...
Module 8: Nails, Hair, Warts and Corns Dr. Aimee Smidt Hair Disorders Androgenic alopecia in men and women Telogen effluvium Alopecia areata Some Basic Science about Hair Follicles The follicle is the embryologically derived structure that produces the hair shaft The hair shaft is what is produced and what we see Hair shafts from mature follicles can be of (at least) 2 basic types Vellus hairs (e.g. cheeks, forehead) Terminal hairs (e.g. axillary, pubic, scalp, beard, eyebrow) How many hair follicles are on the human scalp (approximately)? A) 5,000,000 hair follicles B) 1,000,000 hair follicles C) 200,000 hair follicles D) 100,000 hair follicles E) 100-150 hair follicles How many terminal scalp hairs are normally shed each day? A) 300-500 hairs B) 100-120 hairs C) 10-50 hairs D) 0 hairs What percentage of the human scalp hair is actively growing at any given time: A. 3% B. 5-15% C. 80-90% D. 100% Some Basic Science about Hair Follicles Number of hair follicles on a human body? About 5 million! Most follicles produce vellus hairs Areas of very high density (follicles per square cm) include cheeks and forehead Number of hair follicles on human scalp? About 100,000 Areas of skin without hairs? Glabrous skin Palms and volar surfaces of fingers Soles of feet Mucosal surfaces Why do beards grow where they do? Why does acne occur is certain places more than others? Why does patterned baldness follow a pattern? Some Basic Science about Hair Follicles Hair Follicles structure and function is affected by hormones The type of effect and the strength of the effect (of the hormones) on the follicle depends where on the body the follicle is located Occipital scalp follicles are more independent of hormone signaling Frontal and vertex scalp follicles are more dependent on hormone signaling Central face and forehead follicles are more independent Lateral face and jawline follicles are more dependent Genetic variation also plays an important role in follicle behavior generally and on how hormones affect follicle behavior Some Basic Science about Hair Follicles Hair follicle is an immunologically privileged site “a location in the body where foreign tissue grafts can survive for extended periods of time without immune rejection” other examples = anterior chamber of eye, testis, nervous system tissue, placenta When the immune system targets and damages hair follicles it can be for 2 reasons: Primary attack on hair follicle by stimulated immune system mediators Breakdown of immune privilege leading to hair follicles and/or hair mistakenly appearing as ‘foreign tissue’ to immune system mediators Some Basic Science about Hair Follicles Hair Follicle Cycle (for Terminal Scalp Hair) Anagen (production phase of follicle) 85-90% of scalp hairs at any one time are in this phase A hair follicle in this phase can remain producing a growing hair shaft for 2-6 years Estrogens can prolong time in this phase Androgens can increase growth rate of the hair shaft in more dependent follicles Catagen (regression of follicle) Less than 1% of scalp hairs at any one time A hair follicle in this phase can spend 2-3 weeks regressing Some Basic Science about Hair Follicles Hair Follicle Cycle (for Terminal Scalp Hair) Telogen (resting phase of follicle) 10-15% of scalp follicles at any one time are in this phase A follicle resting in this phase can retain a hair shaft for up to 3 months Exogen (shedding of the hair shaft) Actually occurs in early part of anagen phase as the follicle starts to regenerate and grow a new hair shaft Involves not only a mechanical displacement of old hair shaft by new hair shaft, but a proteolytic process freeing the shaft from the follicle 100-200 hair shafts are shed daily Alopecia = Hair Loss Disruption in Normal Hair Cycle Subtypes – Loss or Decreased development Areata Androgenetic Trichotillomania Inflammatory/Scarring Genetic Subtypes – Shedding Telogen effluvium Anagen effluvium This otherwise healthy 30 yo woman presents with the sudden onset of an asymptomatic patch of alopecia. This condition can be associated with which of the following: A. Hypothyroidism B. Malignancy/Paraneoplastic C. Metabolic syndrome D. Obesity Alopecia Areata Localized (scalp) autoimmune phenomenon May be associated w other autoimmune conditions (thyroid) Follicles “under attack” Non scarring Geometric, clean patterning Can spontaneously improve Episodes may be associated w stressful events Totalis = whole scalp Universalis = whole body Treatment: Topical steroids/anti-inflammatories ?Prednisone/methotrexate Oral minoxidil Topical/oral JAK1 inhibitors Androgenetic Alopecia: Male & Female Male Pattern Most common hair loss in men (70%) Distinct patterning Higher 5-alpha reductase level, Lower total testosterone, Higher free androgens (DHT) Androgen effect → hair follicle diminishes and produces less Female Pattern Affects 40% lifetime Same overall pathogenesis Diffuse thinning or part thickening Trichotillomania Hair pulling behavioral disorder Obsessive-compulsive spectrum; may have associated anxiety or depression Range from mild to severe Treatment supportive/behavioral This is a 30 yo woman with leukemia undergoing treatment with combination chemotherapy. Which stage of hairs has been affected by her treatment: A. Anagen B. Catagen C. Telogen D. All of the above Anagen vs Telogen Effluvium Anagen Insult to hair follicle impairing mitotic activity (chemotherapy) Diffuse shedding of ACTIVELY GROWING hairs Telogen Occurs when abrupt shift occurs, so all telogens are in phase Post-partum, illness, stressor Diffuse shedding all at once of RESTING hairs Spontaneous regrowth Nails Ridging and beading Onycholysis Psoriasis Acute and chronic paronychia Nail nevi and melanoma Onychomycosis (fungal nail infection) Onychodystrophy = Nail Abnormalities Ridging Splitting Thickening Nail pitting/Median tic deformity Nail Psoriasis Onychomycosis = Nail Infection Thickened or discolored nail plate AND: Subungual debris Friable/flaky nail plate Tinea pedis Diagnosis nail clipping PAS stain or culture Usually needs systemic treatment unless 1 nail Terbinafine Topical option - ciclopirox Treat skin too if needed Recurrence COMMON Foot hygiene Paronychia - Acute Erythema, edema, PAIN +/- pus pocket Usually bacterial (staph/strep) Possibly after trauma Possibly med-induced Treatment: Oral antibiotics I&D Warm compresses Ibuprofen +/- topical steroid Paronychia - Chronic Often occupational Soaking/moisture Yeast/fungal Associated onychodystrophy Look at the cuticles! Treatment: Anti fungal/candida oral +/- topical steroid Preventive/vinegar soaks Nail Nevi/Melanoma Melanonychia = Pigment in nail plate Derives from pigment at nail matrix Etiologies Nail lentigo (freckle) Nail nevus ( mole) Nail melanoma (cancer) Mimic: Hemorrhage History/Duration, Age of patient ?Trauma Evolution/widening or irregularity If in doubt, refer! This 30 yo HIV+ gentleman presents with several years history of worsening thick warty papules and plaques on the hands. You suspect that the causative agent is: A. Arsenic exposure B. Hepatitis B virus (HBV) C. Herpes simplex virus (HSV) D. Human papilloma virus (HPV) Verruca (Warts) Human papillomavirus MANY subtypes Vulgaris = Common Palmoplantar Plana = Flat Condyloma acuminata = Genital If extensive, consider immunosuppression Treatment varies: Cryotherapy (Freezing) Topical immunomodulators or irritants Imiquimod Podophyllin Retinoids/tretinoin 5-Fluorouracil Chemical destruction Acids, cantharidin Intralesional (ouch) A healthy 10 yo girl presents for asymptomatic papules around her right eye and chin for the last few months. The family is concerned they are spreading. On close inspection, you see a central umbilication within a papule. You suspect: A. Pre-adolescent acne vulgaris B. Verruca - Human papillomavirus (HPV) C. Molluscum contagiosum (Poxvirus) D. Periocular Herpes simplex virus (HSV) E. Tinea facei (Dermatophyte/Fungus) Molluscum contagiosum is characterized by a papule with central umbilication. Molluscum Contagiosum Pox virus Description: Dome-shaped papules with waxy surface Single or multiple May be pruritic 5mm Location: trunk, face, axillae, genital area Spread by scratching (linear) Curdlike core can be expressed from center Course: spontaneous remission 2-3yrs Treatment Watchful waiting Cantharidin (vesicant) Curetting after topical anesthetic Corns/callus Arise at pressure points Skin lines retained Treatment: Off-loading pressure “Donut” bandages OTC salicylic acid/urea Thank you!