Derm Flashcards
What is pemphigus vulgaris?
Middle aged patient
Due to autoantibodies (igG or complement C3) against desmoglein 3 & 1 (desimosomes)
(+) Nikolsky sign (thin blisters that break easily)
Involvement of oral mucosa
Epidermis breaks- Basement membrane is intact
What is pemphigus pemphigoid?
Older patient
Due to autoantibodies against hemidesmosomes
No involvement of oral mucosa
(-) Nikolsky sign
epidermis lifts off the basement membrane
What is dermatitis herpetiformis?
Cutaneous manifestation of gluten sensitivity (celiac dz)- if not already diagnosed w/ celiac get dz confirmation w/ antibody screening (anti-TTG) and duodenal biopsy
Neutrophilic abscesses (IgA deposits) in the dermal papillae
Itchy bumps on extensor surfaces and buttocks
Definitive Tx by removing gluten from diet
Temporary relieve symptoms w/ treated with dapsone or sulfapyridine
What is tinea versicolor?
Scaly hypoigmented macules/ patches
Caused by Malassezia globosa
treat w/ topical antifungals such as selenium sulfide shampoo or ketoconazole
What is atopic dermatitis (eczema)?
Atopic dermatitis, like its associated asthma, can be triggered/ worsened by triggers such as stress or environmental allergens.
defect in stratum corneum–> extreme pruritis–> lichenification (leathery skin)
Tx w/ topical steroids for inflammation and emollients for healing
Can also give antihistamine for itching relief
oral steroids and UV light therapy only for refractory cases
How to diagnose melanoma?
For mole w/ high melanoma suspicion–> Wide Excisional biopsy
For mole w/ low melanoma suspicion–> punch biopsy
What is porphyria cutanea tarda?
Presents in middle age with fragile hemorrhagic bullae on the backs of the hands and hypertrichosis on the tops of the cheeks.
Increased levels of uroporphyrins and coprporphyrins, causing the urine to have a reddish color and fluoresce under Wood’s lamp
brought on by hormones (think OCPs), alcohol, and hepatitis C and worsened during periods of stress
What is an ash leaf spot?
Hypopigmented macule, often found on the trunk or extremities, enhanced by UV light (Wood’s lamp)
Associated with tuberous sclerosis (TS)
Need to do MRI for brain tumor when pt presents w/ ash leaf spot
Also get a MRI of the abdomen, an echocardiogram of the heart, and, if indicated, an electroencephalogram to look for seizure activity.
What is the treatment for tinea corporis?
Pruritic, erythematous, raised and scaly annular (circular) patch with central clearing
Even “classic” presentations of tinea corporis should have diagnosis confirmed with skin scraping and subsequent KOH microscopy to reveal fungal hyphae.
First-line treatment is with topical antifungals Ketoconazole
What is allergic contact dermatitis (poison ivy)?
Contact with poison ivy causes an allergic contact dermatitis, a type IV hypersensitivity reaction.
Examples of type II hypersensitivity reactions?
Type II hypersensitivity reactions occur when antibodies are formed that target antigens on the surface of cells or tissues. Examples include grave’s disease, myasthenia gravis, and ABO incompatibility.
Examples of type III hypersensitivity reactions?
Type III hypersensitivity reactions are caused by antigen-antibody complexes that deposit in tissues and cause an immune response. Examples include rheumatoid arthritis, systemic lupus erythematosus, and reactive arthritis
What is Stevens-Johnson syndrome?
Stevens-Johnson syndrome (<10% of the body) and Toxic Epidermal Necrolysis (>30% of the body) comprise each end on a spectrum of the same disease.
These patients will have widespread loss of sheets of skin, a positive Nikolsky’s sign, and will be toxic—even critically ill. Most of the cases when a cause is identified evolve as an extreme drug reaction
What is the treatment for scabies?
Scabies infection often presents as the “worst itch of my life” and classically involves the hands, elbows, and male genitalia.
If not clear from the exam, microscopic evaluation of a skin scraping should reveal the mite.
Treatment includes both topical permethrin and sterilization of laundry.
What is the treatment for acne?
Begin with topical retinoids for mild noninflammatory acne (open and closed comedones)
Add benzoyl peroxide in the setting of more inflamed comodones and pustules
if incomplete improvement, adding topical antibiotics
Severe, treatment-resistant acne which may already have scarring, warrants cessation of other therapies and initiation of oral isotretinoin
What is a morbilliform eruption?
Drug eruptions, outside of anaphylaxis, do not occur immediately.
Typical onset for morbilliform eruptions if 7-14 days after the first exposure to offending drug
What is Stevens-Johnson syndrome?
Stevens-Johnson syndrome presents as dusky, irregular, flat, purpuric maculae
It affects less than 10% of the total body surface area.
frequently involves the trunk, oral mucosa and the conjunctivae of the eyes
What drugs/infections are associated w/ Stevens-Johnson syndrome?
Associated w/ sulfonamides, penicillin, and phenytoin (drugs)
Herpes simplex and Mycoplasma (infections).
What is erythema multiforme?
EM is an immune complex mediated hypersensitivity reaction (type IV)
Erythematous target-shaped macules with dusky/purple centers at acral sites (such the palms, fingers and ears)
EM is most commonly triggered by infections (Herpes simplex virus and Mycoplasma)
and certain drugs (cephalosporins)
How does tinea captitis present?
Fungal infection that can cause patchy alopecia in multiple well-circumscribed areas
Confirm the diagnosis with a KOH prep of skin scrapings before treating w/ ORAL antifungal (griseofulvin)
What is Pityriasis rosea?
Nonscaly pink rash—the herald patch—that transforms into scales, sparing the palms and soles
No treatment- self limited
There is no test to confirm pityriasis but rule out serious other dz that have similar rash such as secondary syphilis w/ RPR
Diagnosis of dermatomyositis
proximal muscle weakness and skin manifestations
Muscle biopsy is required for diagnosis
creatine kinase and aldolase will be elevated
Hypomagnesemia symptoms
Hypomagnesemia may be caused by upper or lower gastrointestinal loses.
A history of vomiting or diarrhea is key to the diagnosis.
Grover disease (transient acantholytic dermatosis)
benign, self-limited itchy papular rash over the trunk
may be triggered by excessive sweating, heat, humidity, and sun exposure
Familial benign pemphigus (i.e. Hailey-Hailey disease)
Vesicular lesions and crusting erythematous plaques over the genital area, as well as the chest, neck, and axilla
Burning and pruritus, malodorous drainage
These pts also have multiple asymptomatic longitudinal white bands on the fingernails (unknown why)
Treatment for postherpetic neuralgia
Postherpetic neuralgia (PHN) is a complication of herpes zoster
Nortriptyline has been considered the mainstay of therapy although gabapentinoids are the only FDA approved medications for PHN
Corrected calcium based on albumin level
Corrected calcium = ((4 - albumin) x 0.8) + measured calcium
What causes Familial benign pemphigus (i.e. Hailey-Hailey disease)?
Autosomal dominant disease due to a mutation in ATP2C1, a calcium ATPase pump.
Dermatologic manifestation of Graves disease
Infiltrative ophthalmopathy (proptosis) and infiltrative dermopathy (pretibial myxedema) are characteristic of Graves’ disease but no other causes of hyperthyroidism
amaurosis fugax
transient monocular vision loss- “curtain coming down”
Most commonly due to atherosclerotic disease in the ipsilateral carotid
Requiring a workup for carotid stenosis
Treatment for a nondisplaced scaphoid fracture
Thumb spica cast.
Immobilization is important to prevent avascular necrosis and carpal instability.
When is Percutaneous screw fixation used for scaphoid fractures?
Minimally displaced fracture without angulation and proximal pole fractures
When is Open reduction used for scaphoid fracture?
Significantly displaced/comminuted fractures, associated perilunate dislocation
When is Bone grafting and fixation used for scaphoid injury?
Non-union fracture
First-line treatment for bullous pemphigoid
High-potency topical corticosteroids, such as clobetasol and halobetasol
Von Recklinghausen disease/neurofibromatosis type 1
cafe au lait spots, neurofibromas, freckling in the axillary or inguinal area, and iris hamartomas
scoliosis, spinal deformity, and congenital tibial dysplasia
seizures, mental retardation, or learning disabilities
Staphylococcal scalded skin syndrome (SSSS)
Age < 6 years
Presents with the widespread formation of easily ruptured fluid-filled blisters 24-48 hours after the development of fever and irritability.
No mucosal involvement
No targetoid lesions
Nikolsky Sign Positive
Toxic epidermal necrolysis (TEN)
> 30% of the body surface area is involved
Mucosal involvement
Nikolsky Sign Positive
Targetoid lesions/ dusky red/purple macules
Stevens-Johnson Syndrome (SJS)
Mucosal membranes must be involved or severe conjunctivitis
Nikolsky Sign Positive
Targetoid lesions
Drug reaction with eosinophilia and systemic symptoms (DRESS)
Delayed (Type IV) hypersensitivity reaction
Reaction to the drug occurs 1 week to 2 months following the initial administration
occurs after sulfa antibiotics, antiepileptic medications, or allopurinol
Rash is very itchy and morbilliform, rather than bullous
