Dermatology Flashcards
What is Nikolsky’s sign?
easy removal of skin by just little pressure such that the examiner’s finger is pulling skin off like a sheet
What three diseases are associated with Nikolsky’s sign being present?
- pemphigus vulgaris
- staphylococcal scalded skin syndrome
- toxic epidermal necrolysis
A young pt (30-40s) presents with thin fragile bullae similar to a burn, lesions are painful but not pruritic, involves oral mucosa, destruction is within epidermal layer, Nikolsky’s sign presents, and a possibly have a history of ACE inhibitor/ penicillamine use most likely suffers from …
Pemphigus Vulgaris
antibodies to intracellular spaces of epidermal cells
What is the most accurate test for pemphigus vulgaris?
skin biopsy
What is the treatment for pemphigus vulgaris?
steroids (prednisone)
if steroids uneffecteive use azathioprine/mycophenolate/ cyclophosphamide
An older pt (70-80s) presents with painful, thick walled bullae in which destruction was in the deep skin layers, no oral lesions or Nikolsky’s sign, possible history of using sulfa drugs, and minimal chance of infection or fluid loss most likely suffers from …
Bullous Pemphigoid
What is the best diagnostic test for bullous pemphigoid?
biopsy with immunofluorescent antibodies
What is the best initial treatment for bullous pemphigoid?
systemic steroids (prednisone)
What are alternative treatments for bullous pemphigoid?
- tetracycline
2. erythromycin with nicotinamide
A pt presents with superficial, easily broken bullae, a possible history of ACE inhibitor/ NSAIDs, history of other autoimmune diseases but no oral lesions most likely suffers from …
Pemphigus Foliaceus
What is the diagnostic test and treatment for pemphigus foliaceus?
biopsy; steroids
A pt with a history of alcoholism/ liver disease/ chronic hep C/ oral contraceptive use/ diabetes presents with nonhealing blisters on the sun-exposed parts of the body (face/ back of hands), hyperpigmentation of skin and hypertrichosis (abnormal hair growth) of the face resembling a werewolf most likely suffers from …
Porphyria Cutanea Tarda
photosensitivity reaction to accumulated porphyrins due to abnormal porphyrin metabolism
What is the diagnostic test for porphyria cutanea tarda?
urinary uroporphyrins (elevated 2-5x above the coproporphyrins)
What is the treatment for porphyria cutanea tarda? (5)
- stop drinking alcohol
- stop all estrogen use
- use barrier sun protection (sunscreen, hat, etc)
- remove iron (phlebotomy or deferoxamine)
- chloroquine (increases porphyrins excretion)
A pt develops evanescent wheals and hives within 30 minutes of a new medication/ insect bite/ ingestion of food/ emotionally stressful event/ contact with latex, the lesions are pruritic and last less than 24 hours most likely suffers from …
Urticaria
hypersensitivity reaction mediated by IgE and mast cells
What are three signs of chronic urticaria?
- dermatographism (pressure on skin results in urticaria)
- cold (induces urticaria)
- vibration (induces urticaria)
What is the best treatment for acute urticaria?
H1 antihistamines (diphenhydramine/ benadryl, hydroxyzine, cyproheptadine)
What is the next best step in management of acute urticaria that is life threatening?
add systemic steroids to H1 antihistamines
What is the best treatment for chronic urticaria?
nonsedating antihistamines (loratadine, desloratadine, fexofenadine, cetirizine)
What is the best treatment for urticaria when the trigger can not be avoided?
desensitization (stop beta blocker before procedure bc inhibit epinephrine if needed)
A pt develops a generalized maculopapular eruption that blanches with pressure similar to measles after exposure to a medication or even after the medication has been stopped most likely suffers from …
Morbilliform Rash
typical drug reaction; lymphocyte mediated
What is the treatment for morbilliform rash?
antihistamines
A pt develops targetlike or irislike lesions on the palms and soles, lesions do not occur on mucous membranes, and pt has a history of penicillin/ phenytoin/ NSAIDs/ sulfa use or infection with herpes simplex/ mycoplasma most likely suffers from …
Erythema Multiforme
What is the treatment for erythema multiforme?
antihistamines and treat underlying infection
A pt presents with severe skin lesions involving less than 10-15% of total body surface area, it involves mucous membranes (oral and conjunctiva), and can involve the respiratory tree (requiring mechanical ventilation), Nikolsky’s sign is absent and have a history of penicillin/ sulfa/ NSAIDs/ phenytoin/ phenobarbital use most likely suffer from ..
Stevens Johnson Syndrome
hypersensitivity response to medications
What are the medications that can induce Stevens Johnson syndrome and Toxic Epidural Necrolysis? (5)
- penicillin
- sulfa drug
- NSAIDs
- phenytoin
- phenobarbital
A pt presents with severe skin lesions involving more than 30% of total body surface area, involves mucous membranes and respiratory tree (requiring mechanical ventilation), NIkolsky’s sign is present, full thickness split of skin and have a history of penicillin/ sulfa/ NSAIDs/ phenytoin/ phenobarbital use most likely suffer from ..
Toxic Epidermal Necrolysis
hypersensitivity reaction to medications
What is the best diagnostic test for toxic epidermal necrolysis?
skin biopsy
A pt develops a round, sharply demarcated lesions that leaves a hyperpigmented spot and the lesion occurs at the precise same anatomic site on the skin with repeated drug exposure most likely suffers from ..
Fixed Drug Reaction
What is the treatment for fixed drug reaction?
topical steroids
A pt presents with painful, red raised nodule on the anterior surface of the lower extremity, nodules are tender to palpation but dont ulcerate, last about 6 weeks and are associated with pregnancy/ streptococcal infection/ coccidioidomycosis/ histoplasmosis/ hepatitis/ sarcoidosis/ inflammatory bowel disease/ syphillis/ enteric infection (Yersinia) most likely suffers from …
Erythema Nodosum
What is the treatment for erythema nodosum?
analgesics, NSAIDs and treating underlying disease
What is the best initial test for fungal infections (tinea pedis, tinea cruris, tinea corporis, tinea veriscolor, tinea capitis, onychomycosis)?
potassium hydroxide (KOH) test of skin
What is the most accurate test for fungal infections (tinea pedis, tinea cruris, tinea corporis, tinea veriscolor, tinea capitis, onychomycosis)?
fungal culture (could take up to 6 weeks; not needed unless infection of hair or nail)
What is the best treatment for fungal infection of hair (tinea capitis) or nails (onychomycosis)? (2)
- oral terbinafine
- oral itraconazole
(6 weeks for fingernail, 12 weeks for toenails)
What is a major side effect of terbinafine?
hepatotoxicity (check liver function tests periodically)
What are major side effects of systemic ketoconazole? (2)
- hepatotoxicity
2. gynecomastia
What is the best initial treatment for a bacterial skin infection (impetigo, erysipelas, cellulitis, folliculitis, furuncles, carbuncles)?
- oral dicloxacillin
- oral cephalexin
- oral cefadroxil
What are the IV equivalents of dicloxacillin? (2)
- IV oxacillin
2. IV nafcillin
What is the IV equivalent of cefadroxil?
IV cefazolin
What is the best initial treatment for a bacterial skin infection (impetigo, erysipelas, cellulitis, folliculitis, furuncles, carbuncles) when the patient is allergic to penicillin and it is only a rash?
cephalosporin
What is the best initial treatment for a bacterial skin infection (impetigo, erysipelas, cellulitis, folliculitis, furuncles, carbuncles) when the patient is allergic to penicillin and it is anaphylaxis?
- macrolides (erythromycin, azithromycin, clarithromycin)
- flurorquinolones (levofloxacin, gatifloxacin, moxifloxacin)
- IV vancomycin
(avoid cephalosporins, ciprofloxacin)
What is the best initial treatment for bacterial skin infection (impetigo, erysipelas, cellulitis, folliculitis, furuncles, carbuncles) in a nursing home patient or pt who has been in the hospital for long time?
IV vancomycin
treating for possible MRSA; second line is linezolid or Bactrim
A pt presents with a superficial, weeping, oozing, honey colored and draining skin lesion that occured during warm, humid conditions in a pt who lives in poverty most likely suffers from ….
Impetigo
can causes glomerulonephritis but not rheumatic fever
What is the treatment for Impetigo?
topical mupirocin (if not effective, then oral antistaphylococcal antibiotics)
A pt presents with fever, chills, bacteremia, and bright red angry swollen appearing face most likely suffers from …
Erysipelas
dermis and epidermal Strep pyogenes infection
What is the treatment for Erysipelas?
systemic oral or IV antibiotics
if confirmed Strep, then penicillin G
… is a bacterial infection of the dermis and subcutaneous tissues with Staph and Strep
Cellulitis
tx with IV abx if there is fever, hypotensions, signs of sepsis
A pt presents with redness, oozing lesion around hair follicles after spending time in a whirlpool or hot tub that is nontender most likely suffers from ….
Folliculitis due to Pseudomonas
What is the treatment for folliculitis?
topical mupirocin
What is the treatment for furuncles (small collection of infected material around hair follicle) and carbuncles (localized skin abscess around hair follicle)?
systemic antistaphylococcal antibiotics