DERM1-Table 1 Flashcards
What happens to the epidermis with age?
–Skin more fragile; prolonged turnover rate & ↓ DNA repair
–↓7-dehydrocholesterol + less outdoor activity = insufficient sun exposure = ↓ Vitamin D production
What happens to the dermis with age?
–Loss thickness
–↓ Mast cells & histamine; ↓ vascular supply; ↓ collagen synthesis
What happens to the SQ fat with age?
↓ volume (face & hands) & ↑ volume (abdomen & thighs)
this can lead to pressure ulcers
What does the change in hair with age potentially lead to?
Thinning of hair can lead to baldness/alopecia
What does the decrease in melanin production potentially lead to?
Graying of hair
What does the flattening of the dermo-epidermal jxn lead to?
Skin fragility and propensity to injury
What does capillary fragility lead to?
Actinic purpura
What can atrophy of sweat glands lead to?
Difficult with temp regulation with advanced age
A pt presents with rash…. What are the classification basics?
–Onset: acute vs. chronic –Distribution & pattern –Type of primary lesion & topography –Secondary features –Consistency w/palpation
What are secondary features? What classifies them?
–Crusts: serous, hemorrhagic, purulent
–Scales: hyperkeratosis, accumulated stratum corneum
–Fissure: linear cleft in skin d/t marked dryness, thickening & loss elasticity
–Erosion: loss of epidermis, moist & oozing or crusted
–Ulceration: loss of epidermis & partial superficial dermis: note size, shape & depth along w/traits border, base & surrounding skin
–Excoriation: exogenous, all or part epidermis
-atrophy: epidermal thinning leads to shiny wrinkled appearance, dermal leads too depression
-lichenification” thickening and accentuation of natural skin lines
What are 3 ROS you must ask if a pt presents with a rash?
Fever, pruritus, dysesthesia
Acute fever+ rash = what?
Infectious
Inflammatory
Other
What are the infectious causes of acute fever+ rash?
Bacterial: TSS, scarlet fever, meningococcal
Viral: exanthems, dissem zoster, immunocompromised
Fungal/ protazoal
What are the inflammatory causes of acute fever+ rash?
SJS/TENS/erythema multiforme, pustular psoriasis, rheumatologic (SLE, vasculitis), drug rxn (serum sickness rxn), graft vs. host rxn
What are the other causes of acute fever + rash?
Neoplastic- lymphoma
What are the types of pruritus? What is the ddx for each?
- Primary (aka idiopathic)
- Secondary: derm disorder, allergy, systemic dz, malignancy, toxin d/t renal/hepatic failure, meds, neuro dz, behavioral dz
What are the types of dysesthesia?
Neuropathic and psychocutaneous
What is the DDX for neuropathic dysesthesia?
–Radiculopathy; small fiber polyneuropathies
–Orodynia (burning mouth syndrome); burning scalp syndrome
What is the DDX for psychocutaneous dysesthesia?
Neurotic (psychogenic) excoriation: associated w/OCD, stress, anxiety, depression & bipolar disorder
What can you use KOH prep on?
Scales, hair shafts, subungual and or nail plate
What is dermoscopy?
noninvasive method: allow in vivo evaluation of colors & microstructures in epidermis, dermoepidermal junction & papillary dermis not visible to naked eye
What is dermscopy used to ID?
specific diagnostic patterns related to distribution of colors & dermoscopy structures can better suggest a malignant or benign pigmented skin lesion
When is biopsy indicated?
- Rash or vessels involving dermis: r/o drug rxn, deep tissue infection, vasculitis, E. multiforme
- Atypical moles – malignant suspicion (FHx/PMH – risk factor evaluation, advanced age, fair skin, multiple pigmented nevi)
What are some criteria for atypical moles?
–ABCDE criteria
–Glasgow 7-point checklist: major vs minor features
–“Ugly duckling” sign
What are the types of biopsy?
Shave or punch and excisional
What is a saucerization?
Spoon shaped biopsy
What is an elliptical?
Excision where the entire lesion is removed
What is primary intention?
Wound healing where wound edges heal directly touching each other
–Results in linear scar tissue = goal whenever a wound is sutured closed
What is secondary intention?
wound is left open & filled with granulation tissue which subsequently turns into scar tissue
When is shave biopsy indicated?
predominantly epidermal lesions w/out dermal extension - warts, papillomas, skin tags, superficial BCC & SCC, seborrheic & actinic keratoses
When is shave biopsy not indicated?
When there is a suspicious pigmented lesion
How is a shave biopsy performed?
–Inject anesthetic & create wheal to elevate lesion
–45 angle to shave (#15 scalpel blade, dermablade, double edge razor blade, scissors)
•Remove thin disk of tissue:
What is the healing for a shave biopsy?
Can use silver nitrate or aluminm chloride for hemostasis, keep area clean and covered for one week
A punch biopsy can be both ???? OR ???
Excisional or incisional
When is punch biopsy indicated?
lesion requires dermal or subcutis (bullous lesion, dysplastic or complex nevi, scalp or hair follicle)
What is the limitation of punch biopsy?
narrow deep specimen – may not be wide enough sample because select thickest area of lesion
How is punch biopsy performed?
Punch perpendicular to surface of lesion & rotate through skin until no tension on tissue = full thickness sample; remove tissue w/forceps or needle to minimize crushing
What is the post procedure tx of punch biopsy?
Can do electrocautery or use an agent for hemostasis
Close small site with 2nd intention and large site with steri-strip adhesives or suture
When is a saucerization biopsy indicated?
for pigmented or suspect skin lesions
lesions difficult to remove elliptically d/t cosmesis or anatomic location, vesicobullous disorders, seborrheic keratosis
How is a saucerization biopsy performed?
–45 angle to remove disk of tissue: 1- 4 mm deep combined epidermis & dermis + subcutis
•Nidus of pigment noted s/p biopsy - perform punch or elliptical biopsy
How do you tx a saucer biopsy?
Same as punch but keep area clean and dressed for healing by secondary intention
What is a wedge biopsy?
Incisional, for large lesions - need length, width & depth; stab incision (V or triangular shape) = remove a cone of tissue
