Morphology Matters
This term describes a flat lesion <1 cm in diameter
What is a macule?
A honey-colored crust is classic for this bacterial skin infection
What is impetigo?
This transient, itchy, raised lesion is caused by localized dermal edema and blanching
What is a hive/wheal?
The “slapped cheek” appearance is characteristic of this viral infection
What is fifth disease (parvovirus B19)?
Associated with tampon use and caused by toxins from this bacterium
What is Staphylococcus aureus (or Streptococcus pyogenes)?
A raised, broad, solid lesion >1 cm
What is a plaque?
This viral illness begins on the face and spreads downward, often with Koplik spots inside the mouth
What is measles (rubeola)?
This rash results from direct skin exposure to an allergen or irritant, often presenting with vesicles or linear streaks
What is contact dermatitis?
This viral exanthem follows a high fever that resolves just before the rash appears
What is roseola (HHV-6/HHV-7)?
This intensely pruritic rash with burrows and papules, is often worse at night
What is scabies?
A fluid-filled lesion that is <1 cm in diameter
What is a vesicle?
Main difference between erysipelas and cellulitis
What is borders/demarcation?
This type of hypersensitivity reaction often appears after contact with poison ivy, nickel, or latex.
What is a delayed/type IV hypersensitivity reaction?
Sandpaper-like rash with strawberry tongue
What is scarlet fever
This scalp infection, common in children, can cause hair loss and black dot appearance
What is tinea capitis?
This term refers to a superficial loss of epidermis with no scarring
What is an erosion?
What is Nikolsky's sign?
Gene defect associated with atopic dermatitis
What is the filaggrin (FLG) gene?
Virus causing vesicular rash on hands, feet, and mouth
What is Coxsackie virus A16?
Pain and tenderness may be "out of proportion" to exam, requires urgent surgical debridement
What is necrotizing fasciitis?
These “target lesions” are characteristic of which immune-mediated rash?
What is erythema multiforme?
Classic triad consists of heart defects, cataracts and sensorineural deafness
What is congenital rubella syndrome?
First-line treatments for atopic dermatitis
Caused by entrapment of melanocytes in the dermis during their migration from the neural crest into the epidermis (gray-blue patches)
What is dermal melanocytosis?
This diagnostic preparation is used to allow clinicians to better visualize fungal elements under a microscope
What is KOH prep?