MTB 3 - Dermatology Flashcards
How does pemphigus vulgaris present?
Painful bullae that are easily ruptured
Involvement of the mouth
Nikolsky’s sign
What’s the pathophysiology of pemphigus vulgaris?
IgG Antibodies against desmosomes.
Desmosomes allow cell-to-cell adhesion
What causes pemphigus vulgaris?
Idiopathic
ACE-I
Penicillamine
What 3 things can give Nikolsky’s sign?
Pemphigus vulgaris
SSSS
Toxic epidermal necrolysis
How to diagnose pemphigus vulgaris?
Biopsy of skin showing autoantibodies on immunofluorescent studies in a netlike pattern
Treatment of pemphigus vulgaris?
Prednisone
If inneffective, use azathioprine
Without treatment, this condition is fatal
Describe bullous pemphigoid:
Much milder disease than pemphigus vulgaris
Bullae stay intact so less fluid loss and infection
Mouth involvement is uncommon
Pathophysiology of bullous pemphigoid?
IgG antibodies against hemidesmosomes (basement membrane). Linear immunofluorescence.
How to diagnose bullous pemphigoid?
Skin biopsy showing linear immunofluorescence of IgG against the hemidesmosomes of the basement membrane
Treatment for bullous pemphigoid?
Prednisone
What ages does pemphigus vulgaris and bullous pemphigoid present?
Pemphigus vulgaris: 30’s and 40’s
- Life-threatening
- Thin and fragile bullae
- Mouth involved
- Nikolsky’s
Bullous pemphigoid: 70’s and 80’s
- Thick and intact bullae
- No mouth involvement
What is porphyria cutanea tarda (PCT)?
Disorder of porphyrin metabolism –>
High accumulation of porphyrins –>
Causes photosensitivity reaction
List 5 associations with PCT:
Alcoholism Liver disease -Chronic Hep C -Hemochromatosis OCP Diabetes
How does PCT present?
Nonhealing blisters on sun-exposed part of body
Hyperpigmentation of skin
Hypertrichosis of face (excess hair)
How to test for PCT?
Urinary uroporphyrins will be 2-5x higher than coproporphyrins
How to manage PCT?
Stop alcohol
Stop estrogen use
Use sun protection
Phlebotomy to remove iron or deferoxamine
Chloroquine increases excretion of porphyrins
What is urticaria?
A localized, cutaneous anaphylaxis without hypotension or hemodynamic instability.
Caused by a hypersensitivity reaction by IgE and mast cell activation
Results in wheals and hives very pruritic
When is the onset of wheals and hives in urticaria? How long does it last?
Within 30 minutes of exposure. Lasts for
Most common medication causes of urticaria:
Aspirin NSAIDs Morphine Codeine Penicillin Phenytoin Quinolones
Other common causes of urticaria besides medications:
Insect bites
Foods (peanuts, shellfish, tomatoes, strawberries)
Latex
Emotions (occasionally)
Chronic urticaria is associated with:
Pressure on skin
Cold
Vibration
How to treat urticaria?
Always: Antihistamines (diphenhydramine, hydroxyzine, cyproheptadine)
Life-threatening: Systemic steroids
Chronic therapy: Nonsedating antihistamines (loratadine, cetirizine)
When do you do desensitization for someone with urticaria?
When the trigger can’t be avoided (bee stings in a farmer).
What must you stop taking prior to desensitization?
Beta-blockers (cause you might need to use epinephrine which uses beta receptors)
What is a morbilliform rash?
Typical type of drug reaction to which the pt is allergic
Milder version of urticaria
Resembles measles
Generalized maculopapular eruption that blanches w/pressure
Treatment of morbilliform rash?
Antihistamines
How does erythema multiforme present?
Targetlike lesions on palms and soles
Erythema multiforme is caused by what things?
Penicillins Phenytoin NSAIDs Sulfa drugs HSV or mycoplasms infection
Treatment of erythema multiforme?
Antihistamines
Describe Stevens Johnson Syndrome:
Hypersensitivity reaction
Treatment of SJS?
IV immunoglobulin
Cyclophosphamide
Steroids don’t work
What things can cause SJS?
Penicillins
Phenytoin
NSAIDs
Sulfa drugs
Describe toxic epidermal necrolysis:
Most serious cutaneous hypersensitivity reaction 30-100% BSA 40-50% mortality Nikoslky's sign Sepsis most common cause of death
Should you give prophylactic antibiotics to pts with TEN?
No
How to diagnose TEN?
Skin biopsy
Treatment of TEN?
Doesn’t say
Don’t give steroids
What is a fixed drug reaction?
Localized allergic drug reaction at precisely the same location as drug exposure.
Round, sharply demarcated lesions that leave a hyperpigmented spot at site after they resolve
How to treat a fixed drug reaction?
Topical steroids
What does erythema nodosum look like?
Painful, red, raised nodules on shins
Nodules are tender, don’t ulcerate, and last 6 weeks
Name 9 conditions that cause erythema nodosum:
- Pregnancy
- Recent strep infection
- Coccidioidomycosis
- Hisoplasmosis
- Sarcoidosis
- IBD
- Syphilis
- Hepatitis
- Enteric infections (Yersinia)
Treatment of erythema nodosum?
Analgesics and NSAIDs
Treat underlying disease
Best initial test for cutaneous fungal infections:
KOH test of skin (dissolves everything but fungus)
Most accurate test for cutaneous fungal infections:
Culture the fungus
Treatment for oncyhomycosis (nails) or tinea capitis (hair)?
Oral terbinafine
Oral itraconazole
6 weeks for fingernails - 12 weeks for teonails
What is a problem with terbinafine and how do you watch out for it?
Hepatotoxicity
Check LFTs periodically
How does griseofulvin compare to terbinafine?
Not nearly as efficacious. Must use for 6-12 MONTHS
All other fungal infections that don’t involve hair or nails can be treated with topical medications. Name the meds:
Ketoconazole
Econazole
Clotrimazole
Miconazole
How does the efficacy of the topical antifungals compare?
No clear difference when used topically
If ketoconazole is given orally, what are some serious side-effects?
Hepatotoxicity and gynecomastia
-This is why it’s nto given for hair or nails
Describe impetigo:
Confined to epidermis
Weeping, oozing, honey-colored
Very contagious
What bugs cause impetigo?
Staph Strep pyogenes (Group A)
Serious complication of impetigo?
Glomerulonephritis
Treatment of impetigo?
Topical mupirocen
If inneffective, use PO oxacillin/nafcillin
What layers does eryisepelas effect?
Epidermis and dermis
What bug causes erysepelas?
Strep pyogenes (group A)
Presentation of eryisepelas?
Fever, chills
Bright red, swollen appearance to the face
Treatment of erysipelas?
Systemic PO or IV:
Penicillin G or ampicillin if culture says it’s Strep
Otherwise:
Dicloxacilin
Cephalexin
Vanc if MRSA is suspected
What layers does cellulitis effect?
Dermia and subcutaenous tissues
Bugs causing cellulitis?
Staph
Strep
What are folliculitis, furuncles, and carbuncles? What bug is responsible?
These are different degrees of severity of a staph infection around a hair follicle. Pseudomonas from hot tub can cause it, too.
Folliculitis
Treatment of folliculitis?
Topical mupirocen
Treatment of furuncles and carbuncles?
Drain carbuncles
Systemic dicloxacillin or cefadroxil for both
Describe what necrotizing fasciitis is (not the sxs):
Extremely severe, life-threatening infection of skin
Begins as cellulitis and dissects into fascial planes of skin
Symptoms of necrotizing fasciitis:
Very high fever Pain out of proportion to appearance Bullae Palpable crepitus Portal of entry in to skin
What bugs cause necrotizing fasciitis?
Streptococcus
Clostridia
What increases risk of necrotizing fasciitis?
DM
How to diagnose necrotizing fasciitis?
Elevated CPK
X-ray, CT, or MRI showing air in tissue or necrosis
Surgical debridement (best way to confirm diagnosis)
Treatment for necrotizing fasciitis?
Surgical debridement is mainstay
Zosyn
If there’s definite Strep pyogenes, tx is clindamycin and penicillin
What is paronychia?
Infection in the skin surrounding a nail
Treatment of paronychia?
Small incision for drainage +
Anti-staph drugs (nafcillin/oxacillin)
HSV skin infection presentation:
Multiple, painful vesicles
How to treat HSV infections?
ORAL Acyclovir, famciclovir, or valacyclovir if exam is obvious
Topical does nothing
How to treat acyclovir-resistant herpes?
Foscarnet
Best initial test for HSV?
Tzanck smear
Most accurate test for HSV?
Viral culture (grows in 1-2 days)
Complications of varicella in kids?
Pneumonia
Hepatitis
Dissemination
Treatment of shingles?
Acyclovir to reduce risk of postherpetic pain
Steroids for elderly pts with severe pain
For postherpetic pain: Gabapentin
How does HPV present?
White or flesh-colored, translucent heaped-up lesions
Another term for HPV lesions?
Condylomata acuminata
Diagnostic testing for Condylomata acuminata?
No form of testing is routinely necessary
Treatment of Condylomata acuminata?
Take your pick from: Cryotherapy w/liquid nitrogen Laser Trichloroacetic acid Porodphyllin to melt them (avoid in pregnancy) Imiquimod is local imunostimulant
How does primary syphilis present:
Chancre = Ulceration with heaped-up indurated edges. Painless
Best initial test for primary syphilis?
Darkfield exam (not VDRL/RPR due to 25% false neg rate)
How to treat primary or secondary syphilis?
Single IM dose of penicillin
Doxycycline if allergic
How does secondary syphilis present?
Generalized copper-colored, maculopapular rash, especially on palms and soles
Best initial test for secondary syphilis?
VDRL and RPR (100% sensitivity)
How does scabies present?
Very pruritic lesions in web spaces of hands and feet, penis, and breast.
May see burrows and excoriations around small vesicles
Where does scabies spare?
Head
How to test for scabies?
Scraping out organism after mineral oil is applied to a burrow
Treatment of scabies?
Permethrin
What is pediculosis?
Lice and crabs
Where does pediculosis occur on the body?
Hairy places
Easily transmitted by hairbrushes and hats
Also through sexual contact (90% transmission from a single contact)
How to diagnose pediculosis?
Viewing the organism on the hair under magnification
Treatment of pediculosis?
Permethrin
The rash of lyme disease occurs how long after the bite?
7-10 days
What do you do if a rash looks erythematous with a central clearing and is at least 5cm in diameter?
It’s definitely Lyme disease, go directly to treatment
How to treat Lyme disease?
PO Doxycycline or amoxicillin
What will happen if you don’t treat lyme disease?
66% develop joint disease
Neurologic or cardiac disorders
What causes toxic shock syndrome?
Staph infection from:
- Nasal packing
- Retained sutures
- Tampons
How to diagnose toxic shock syndrome?
Must have:
- Fever >102
- Systolic
What can be found on labs with toxic shock syndrome?
High creatinine, CPK, LFTs
Low platelet count
CNS dysfunction (confusion)
How to treat toxic shock syndrome?
Fluid resuscitation
Pressors (dopamine)
Oxacillin/nafcillin
Vanc or linezolid for MRSA
How is SSSS different from TSS?
It has normal BP and doesn’t affect liver, CNS, etc
Which layers of skin does SSSS affect?
Only the superficial granular layer
Management of SSSS?
Admit to burn unit
Give oxacillin/nafcillin
How is anthrax usually acquired?
From infected livestock
-Occupational hazard of wool sorters
How does an anthrax infection present?
Cutaneous infection
-Inflamed papule that develops black central necrosis
What does anthrax mean in Greek?
Coal
Hwo to diagnose anthrax?
Gram stain and culture of lesion
Treatment of anthrax?
Ciprofloxacin or doxycycline
Describe melanoma
Malignant Grow in size Irregular borders Uneven shape Inconsistent coloring
Most prognostic factor for skin cancer?
Tumor thickness
Tx of melanoma?
Excision
Describe seborrheic keratosis
Benign
Hyperpigmented lesions in elderly
Stuck-on appearance
Common on face, shoulders, chest, and back
Treatment of seborrheic keratosis?
Liquid nitrogen OR curettage
This would only be done for cosmetic reasons as they are perfectly benign
Describe actinic keratosis:
Precancerous
Sun-exposed area of body in older pts
May be tender
Treatment of actinic keratosis?
Sunscreen to prevent progression/recurrenc Removed with: -Cryotherapy -Topical 5FU -Imiquimod
Describe squamous cell carcinoma
Sun-exposed skin surfaces in elderly
Common on lip (b/c of tobacco)
Ulceration
Metastases are rare (3-7% of pts)
Desribe Basal cell carcinoma:
Most common skin cancer
Shiny, pearly appearance
Telangiectasias
Dx of basal cell?
Shave or punch biopsy
Tx of basal cell?
Surgical removal Mohs microsurgery (instant frozen section and stop when margin is clean)
Describe Kaposi’s sarcoma:
Purplish lesions on skin
Usually in HIV pts with CD4
Tx of Kaposi’s?
- Start antiretroviral therapy and raise CD4 count
- Adriamycin and vinblastine (both specific therapy for Kaposi’s)
Describe psoriasis:
Silvery scales on extensor surfaces
Nail pitting
Can be extensive
Treatment of psoriasis?
Emollients (Eucerin, lubriderm, vaseline, etc)
Topical vitamin A (Tazarotene)
Topical Vitamin D (Calcipotriene)
Methotrexate for severe, widespread disease
Newest therapies are etanercept, infliximab, efalizumab
Describe atopic dermatitis
Red, itchy plaques
Flexor surfaces
High IgE levels
Treatment of atopic dermatitis:
Preventive - emollients and avoid hot water/drying soaps
Active disease - Topical steroids, antihistamines, phototherapy, avoid scratching
Describe seborrheic dermatitis
- Oversecretion of sebaceous material from a hypersensitivity reaction to superficial fungal organism, pityrosporum ovale
- Dandruff
- Scaly, greasy flaky skin on a red base on scalp, eyebrows, and nasolabial fold
- Cradle cap in infants
Treatment for seborrheic dermatitis:
- Topical hydrocortisone
- Topical ketoconazole or selenium sulfide
- Zinc pyrithione as a shampoo
What is stasis dermatitis?
- Hyperpigmentation from built-up hemosiderin
- Occurs from chronic LE-venous insufficiency
- Irreversible
Tx of stasis dermatitis?
Prevent progression with elevation of legs + compression
Describe contact dermatitis:
- Hypersensitivity to soaps, detergents, latex, jewelry
- Linear streaked vesicles (esp when from poison ivy)
How to definitively diagnose contact dermatitis?
Patch testing
Treatment of contact dermatitis?
Antihistamines and topical steroids
Describe pityriasis rosea:
Pruritic eruption that begins with herald patch (75% of the time)
Erythematous, salmon-colored
Looks like secondary syphilis (spares palms and soles though)
Tx of pityriasis rosea?
Self-limited
Will resolve in 8 weeks
Caused by HSV 6 and 7 (same that cause roseola)
Treatment of mild acne:
Topical clindamycin, erythromycin
Topical retinoids
Treatment of moderate acne:
Benzoyl peroxide + retinoids (tazarotene, tretinoin)
Tx of severe, cystic acne:
Oral minocycline, tetracycline, clindamycin, isotretinoin
What to do before starting an oral retinoic acid derivative?
Pregnancy test
Make sure pts are on OCPs if female of childbearing age
