Skin Structure
Bullous Disorders
Inflammatory Disorders
Infections
Genetic Disorders
100
This epidermis layer provides the main barrier to water loss and contains dead keratinocytes.
What is the stratum corneum?
100
A 60-year-old woman presents with painful oral ulcers and flaccid skin bullae. Nikolsky sign is positive.
What is pemphigus vulgaris?
High yield: antibodies are against desmosomes!
100
A child with asthma presents with intensely pruritic rash in the antecubital fossae and dry skin.
What is atopic dermatitis?
Type 1 HSN Reaction!!
100
A child presents with lesions around the mouth after a minor scratch.
What is impetigo?
Usually Staph or Strep!
100
A child presents with multiple fractures.
What is osteogenesis imperfecta? AKA brittle bone disease
↓ Type I collagen synthesis by osteoblasts → ↓ osteoid production → weak bones (↑ fractures)
200
These structures connect keratinocytes to each other and are targeted in pemphigus vulgaris.
What are desmosomes (desmoglein)?
200
An elderly patient develops pruritic, tense bullae without mucosal involvement. Nikolsky sign is negative.
What is bullous pemphigoid?
High yield: antibodies are against hemidesmosomes!
200
A patient presents with well-demarcated plaques on extensor surfaces with silvery scale. Auspitz sign +
What is psoriasis?
200
A patient has recurrent painful vesicles on the lip that resolve and recur in the same location. Usually preceded by a tingling sensation.
What is herpes labialis?
Classically caused by HSV 1!
200
What is Ehlers-Danlos syndrome (defective collagen synthesis)?
- The classical type of Ehlers-Danlos syndrome (joint and skin symptoms) is caused by a mutation in type V collagen
-Compared to the vascular type of EDS which is caused by a type III collagen deficiency
300
A 10-year-old boy has diffuse hypopigmentation of skin, hair, and eyes. Labs show inability to synthesize melanin despite normal melanocyte number. This enzyme affected is _
What is tyrosinase?
300
A 4-year-old child develops diffuse erythema and superficial skin sloughing after a skin infection. Mucosa is spared. Nikolsky sign +
What is staphylococcal scalded skin syndrome?
Mechanism: Toxin-mediated cleavage of desmoglein 1 causing superficial epidermal splitting in children.
300
A patient with hepatitis C develops pruritic, purple, polygonal papules on the wrists. Patient also has mouth findings seen above:
What is lichen planus?
Histology findings: Hypergranulosis and saw tooth pattern
300
A 65 year old male develops a painful unilateral vesicular rash.
What is varicella-zoster virus AKA Shingles?
Dermatomal distribution!
300
A tall, thin adolescent presents with decreased visual acuity. Exam shows superotemporal lens displacement and long, slender fingers. Echocardiogram reveals dilation of the ascending aorta.
What is Marfan syndrome (fibrillin-1 mutation)?
400
These antigen-presenting cells contain rod-shaped “tennis racket” granules and mediate cutaneous immunity.
What are Langerhans cells?
Birbeck granules!
400
A patient recently started on allopurinol develops widespread skin necrosis with mucosal involvement and positive Nikolsky sign.
Hint: >30% of Body Surface Area (BSA) affected
What is toxic epidermal necrolysis?
Severe drug reaction with full-thickness epidermal necrosis and mucosal involvement.
400
A young man with severe nodulocystic acne is started on a drug that decreases sebaceous gland size. Hint: highly teratogenic!
What is isotretinoin?
400
A 7 year old girl has severe itching at night with linear burrows between fingers. Household members are also affected.
What is Sarcoptes scabiei?
400
A 28-year-old man with a history of long limbs and prior lens surgery presents with sudden, severe chest pain radiating to his back. Blood pressure differs between arms. Imaging shows an intimal flap in the ascending aorta.
What is aortic dissection?
500
Vitamin C is required for this step in collagen synthesis.
What is hydroxylation of proline and lysine?
500
A young adult presents with intensely pruritic vesicles on elbows and knees. He has chronic diarrhea.
Hint: Biopsy shows IgA deposition in dermal papillae.
What is dermatitis herpetiformis?
500
An obese patient presents with recurrent painful nodules and sinus tracts in the axillae and groin.
What is hidradenitis suppurativa?
Smoking also increases risk!
500
A patient presents with a painless genital ulcer followed weeks later by a widespread maculopapular rash involving palms and soles.
What is syphilis (Treponema pallidum)?
Specifically secondary syphilis!
500
A 6-month-old boy presents with developmental delay, hypotonia, and seizures. His hair is sparse, brittle, and “kinky.” Laboratory studies reveal low serum copper levels due to impaired intestinal absorption.
What is Menkes Disease?
Missing enzyme: Lysyl oxidase (with copper as cofactor)