Clinical questions - Dermatology Flashcards
Melanoma characteristics
ABCDE
Asymmetry Border irregularity Color variability Diameter >= 6mm Evolving
If suspected, perform excisions biopsy. Shave bx will not tell you depth
Characteristics and treatment of Herpes Zoster
painful rash, groups of erythematous vesicles in dermatomal distribution - one sided but can become bilateral if disseminated disease
Tx:
within 72 hrs of onset start 7 day course of antivirals - acyclovir, valacyclovir, famciclovir
supportive analgesia
If over 50 yo - zoster vaccine
Lichen plants description, associated diseases, treatment
pruritic rash, often wrists and shins, composed of violaceous, polygonal papule
Unknown cause but associated with Hepatitis C infection and medications
Tx with topical corticosteroids
Scabies infection presentation and treatment
severe itching of skin, “whole body except head”. On exam multiple small, erythematous papule with occasional hemorrhagic crusts. raised gray colored tracts on webbing between fingers
Tx: 1st line topical permethrin; oral ivermectin
Congenital dermal melanocytosis
“mongolian spot” - blue-gray macule
MC in lumbosacral region
Fades in first 2 yrs of life
reassure and document in the medical record
Steven Johnson Syndrome/Toxic epidermal necrolysis presentation and treatment
fever, malaise, arthralgias
conjunctivitis, oral ulcers, erythematous target-like lesions over face, trunk, extremities
Over next few days develop bullies lesions with skin sloughing
Admit to ICU or burn unit Stop drug Wound care: dressings/debridements Supportive care: IVF, elytes prn, pain control Monitor for bacterial superinfection
SJS/TEN associated causes
Drugs: Allopurinol Carbamazepine Lamotrigine Phenobarbital Phenytoin Sulfamethoxazole sulfasalazine
Infectious:
Mycoplasma pneumoniae
CMV
Red man syndrome
pruritic erythematous rash involving face, neck, upper body associated with IV Vanc
Mechanism: direct mast cell activation
Tx:
Stop infusion of IV Vanc
Give diphenhydramine and ranitidine
After symptoms subside restart IV Vanc at slower rate
Erythema nodosum
painful reddish violet nodules over shins 2/2 hypersensitivity reaction
Dx confirmed by Bx
Causes MC - Strep pharyngitis Sarcoidosis TB Fungal: coccidioidomycosis, histoplasmosis, blastomycosis IBD Pregnancy and OCP use Idiopathic
Erythema multiforme
painful oral erosions and rash consisting of raised target lesions on trunk and extremities - immune mediated s/p infection
MC - HSV
Mycoplasma pneumonia
Self limited - resolves over a few weeks
Symptomatic tx:
- pruritis: topical corticosteroids, oral antihistamines
- Oral involvement: PO prednisone
No indication for acyclovir unless recurrent with HSV cause to ppx
erythema multiforme vs SJS/TEN
erythema multiforme s/p infection
SJS/TEN s/p drug administration
Stasis dermatitis
typically bilateral - if unilateral r/o cellulitis
2/2 chronic venous insufficiency
Tx: elevate legs, compression stockings, treat underlying cause of venous insufficiency
Scalded skin syndrome
infant with fever, irritability
erythematous rash around the mouth that generalizes and flaccid blisters appear. Upper layer of skin sloughs with gentle lateral pressure (+ Nikolsky sign)
Differentiated from SJS/TEN: no mucous membrane involvement
Bx to confirm Dx
2/2 exotoxin from S. aureus
Tx: IV Nafcillin or Oxacillin
Supportive: emollients, IVF, elytes prn
Actinic keratosis
erythematous scaly lesions, +/- horns, involving sun exposed areas, risk of transformation to SCC
Tx: Cryotherapy Curettage Topical 5-FU Topical imiquimod Topical ingenue mebutate Photodynamic therapy
Pemphigus vulgaris
Flaccid, easy to rupture bullae (+nikolsky)
almost always has oral lesions
Tx:
Systemic glucocorticoids: prednisone, prednisolone
+/- immunomodulator: azathioprine, mycophenolate
More severe than bullous pemphigoid - higher mortality rate
Bullous pemphigoid
Tense, hard bullae that are difficult to rupture
Oral lesions less common - 10-30%
Tx:
TOPICAL corticosteroids: clobetasol
+/- immunomodulator: azathioprine, mycophenolate
Porphyria cutanea tarda
skin blisters with sun exposure
associated with chronic Hep C and other liver disease
Mechanism:
Defect in uroporphyrinogen decarboxylase (found in liver and RBCs) leads to elevated levels of uroporphyrinogen in blood and urine
Tx: Avoid triggers: EtOH, estrogens, polyhalogenated hydrocarbons Phlebotomy to lower Fe load Chloroquine Treat underlying cause
Pityriasis rosea
starts as erythematous plaque - “Harold’s patch”
1 week later has onset of multiple salmon-colored, oval plaques in a “Christmas tree” pattern over chest and back
Possibly related to HHV7 or HHV8 infection
Self limited, offer reassurance
If pruritic can use topical corticosteroids
If severe can use acyclovir to treat underlying infection cause
Isotretinoin
Used to treat severe nodular acne that has not responded to topical or oral medications
Extremely teratogenic, can cause spontaneous abortions, severe fetal malformations
Provide counseling and education
Must have 2 negative pregnancy tests prior to starting, with frequent repeat testing throughout treatment course
Use 2 forms of birth control
Monitor labs:
Lipids - cause hyperlipidemia
LFTS - hepatotoxicity
CBC - bone marrow suppression
Classic description of nodular basal cell carcinoma
papular, nodular lesion
curly or translucent look to it
telangectasia
Treatment for lice
Permethrin MC but growing resistance Malathion Benzyl alcohol Spinosad Ivermectin
2nd line - lindane, risk of neurotoxicity
atopic dermatitis
dry, pruritic skin with erythematous patches with scaling on exam. Often involve face, neck, flexor surfaces (antecubital and popliteal fosse)
1/3 of children develop asthma
Classic description of cutaneous squamous cell carcinoma
Involves head and neck MC but can be anywhere
Papule, plaque, or nodule
Ulceration - “non-healing”, “poorly healing”
Crusting
Hyperkeratosis in well differentiated lesions
Furuncle vs carbuncle
“Painful boil”
Furuncle: small abscess around 1 hair follicle
Carbuncle: multiple follicules involved
Smaller: apply warm compresses
Larger:
-I&D
+/- abx to cover MRSA: Clinda, bactrim
