Dermatology Flashcards
1
Q
Pathophysiology of pemphigus vulgaris?
A
LIFE-THREATENING autoimmune disease of unclear etiology in which the body produces antibodies against antigens in the intercellular spaces of the epidermal cells
2
Q
Causes of pemphigus vulgaris?
A
- idiopathic
- ACE inhibitors
- penicillamine
3
Q
Classic sign seen in pemphigus vulgaris?
A
Nikolsky’s sign - easy removal of the skin by just a little pressure (also seen in SSSS, TEN)
4
Q
Dx of pemphigus vulgaris?
A
Bx
5
Q
Tx of pemphigus vulgaris?
A
- glucocorticoids (e.g. Prednisone)
- when steroids ineffective –> Azathioprine, Mycophenolate, Cyclophosphamide
6
Q
Causes of bullous pemphigoid?
A
can be drug-induced (e.g. sulfa drugs and others)
7
Q
How are bullous pemphigoid blisters different from pemphigous vulgaris?
A
- BP: fracture of skin is deeper, bullae thicker walled, much less likely to rupture; skin better protected
- PV: fracture of skin more superficial, much easier to remove skin
8
Q
Dx of bullous pemphigoid?
A
bx w/ immunofluorescent antibodies
9
Q
Tx of bullous pemphigoid?
A
- systemic steroids (e.g. prednisone)
- OR tetracyline OR erythromycin with nicotinamide
10
Q
Age differences between bullous pemphigoid and pemphigus vulgaris?
A
BP: 70s and 80s
PV: 30s and 40s
11
Q
Mouth involvement in bullous pemphigoid vs. pemphigus vulgaris?
A
BP: No
PV: Yes
12
Q
Cause of pemphigus foliaceous?
A
- in association w/ other AI diseases
- drug-induced (ACE inhibitors, NSAIDs)
13
Q
How is pemphigus foliaceous different from BP and PV?
A
-foliaceous is much more superficial, intact bullae not seen because they break so easily, no oral lesions
14
Q
Dx of pemphigus foliaceous?
A
Bx
15
Q
Tx of pemphigus foliaceous?
A
steroids (e.g. Prednisone)
16
Q
What is porphyria cutanea tarda?
A
Disorder of porphyrin metabolism resulting in a photosensitivity reaction to an abnormally high accumulation of porphyrins
17
Q
What diseases/medications are a/w porphyria cutanea tarda?
A
- alcoholism
- liver disease (e.g. due to chronic Hep C or hemochromatosis)
- OCPs
- DM
18
Q
How does PCT present?
A
- nonhealing blisters on sun-exposed parts of the body (e.g. backs of hands & face)
- hyperpigmentation of face
- hypertrichosis of face
19
Q
Dx of PCT?
A
test for urinary uroporphyrins (elevated 2-5X higher than coproporphyrins)
20
Q
Tx of PCT?
A
- stop drinking alcohol
- stop all estrogen use
- use barrier sun protection
- use phlebotomy to remove iron (add deferoxamine if phlebotomy not possible)
- chlorquine (increases excretion of porphyrins)
21
Q
Pathophysiology of urticaria?
A
HSR, most often mediated by IgE and mast cell activation –> evanescent wheals and hives. A type of localized cutaneous anaphylaxis but w/o hypotension and hemodynamic instability
22
Q
Presentation of urticaria?
A
wheals and hives w/i 30 min of inciting factor, lasts < 24 hrs. Itching prominent
23
Q
Most common causes of urticaria?
A
- meds (ASA, NSAIDs, morphine, codeine, PCNs, phenytoin, quinolones)
- insect bites
- foods (peanuts, shellfish, tomatoes, strawberries)
- emotions (occasionally)
- latex contact
24
Q
Tx of urticaria?
A
- H1 antihistamines (Diphenhydramine, hydroxyzine, cyproheptadine)
- Life threatening reactions: add systemic steroids
- chronic Tx: newer nonsedating antihistamines (e.g. loratadine, desloratadine, fexofenadine, cetirizine)
- when trigger cannot be avoided –> desensitization
25
What is a morbilliform rash?
milder version of an HSR than urticaria; "typical" type of drug reaction; resembles measles - generalized maculopapular eruption that blanches with prsesure
26
What is the usual cause of a morbilliform rash?
PCN, sulfa, allopurinol, phenytoin drugs
27
How is morbilliform rash treated?
antihistamines (steroids rarely necessary)
28
What are the causes of erythema multiforme?
- PCNs
- phenytoin
- NSAIDs
- sulfa drugs
- infection with HSV or mycoplasma
29
How does erythema multiforme present?
targetlike lesions, esp on palms and soles
30
Tx of erythema multiforme?
antihistamines, Tx of underlying infection
31
Cause of Stevens-Johnson syndrome?
HSR to meds (e.g. PCNs, sulfa drugs, NSAIDs, phenytoin, phenobarbital)
32
What % of body affected in SJS? Overall mortality?
<5-10%
33
Tx of SJS?
management in burn unit; possible value - IVIG, cyclophosphamide, cyclosporine, thalidomide
Steroids have no benefit
34
How does death occur in SJS?
from infection, dehydration, malnutrition
35
What is the most serious version of cutaneous HSR?
TEN
36
What % of body affected in TEN? Overall mortality?
30-100%; 40-50%
37
How does skin appear in TEN?
skin easily sloughs off; Nikolsky's sign present
38
Cause of TEN?
drugs
39
Most common cause of death in TEN?
sepsis (but Abx and steroids not indicated)
40
Dx of TEN?
bx
41
What is a fixed drug reaction?
localized allergic drug rxn that recurs at exactly the same site on skin with repeated drug exposure
42
How do fixed drug reaction lesions appear?
round, sharply demarcated lesions that leave a hyperpigmented spot at site after they resolve
43
Tx of fixed drug reaction?
steroids
44
How does erythema nodosum present?
-painful red raised tender non-ulcerative nodules on the anterior surface of the lower extremities which last ~ 6 weeks
45
Cause of erythema nodosum?
infection/inflammation:
- pregnancy
- recent strep infection
- coccidioidomycosis
- histoplasmosis
- sarcoid
- IBD
- syphilis
- hepatitis
- enteric infections (e.g. Yersinia)
46
Tx of erythema nodosum?
analgesics and NSAIDs, treat underlying disease
47
Name some dermatologic fungal infections.
Tinea pedis, tinea cruris, tinea corporis, tinea versicolor, tinea capitis, onychomycosis
48
What is the best initial test for dermatologic fungal infections?
KOH test of skin (KOH has ability to dissolve the epithelial cells and collagen of the nail but not the fungus)
49
What is the most accurate test for dermatologic fungal infections?
fungal culture (but molds that grow on the skin [dermatophytes] take up to 6 weeks to grow)
50
Tx of dermatologic fungal infections?
-For onychomycosis or tinea capitis --> oral terbinafine or itraconazole (6 weeks for fingernails and 12 weeks for toenails)
51
What side effect of terbinafine must you be wary of?
hepatotoxicity (check LFTs periodically)
52
What Tx's can be used for all of the other fungal infections of the skin that don't involve hair/nails?
topical meds (Ketoconazole, Clotrimazole, Econazole, Terbinafine, Miconazole, Sertaconazole, Tolnaftate, Naftifine)
53
Why shouldn't you use Ketoconazole systemically?
causes hepatotoxicity and gynecomastia
54
Name some bacterial infections of the skin.
Impetigo, erysipelas, cellulitis, folliculitis, furuncles, carbuncles, necrotizing fasciitis, paronychia
55
What is Tx for bacterial skin infections, in general?
- Dicloxacillin, cephalexin (Keflex), or cefadroxil (Duricef)
- IV equivalent = oxacillin/nafcillin, cefazolin
- If pt has a PCN allergy but reaction is only a rash, then cephalosporins can be used
- If PCN allergy is anaphylaxis, treat with macrolides (e.g. erythromycin, azithromycin, clarithromycin) or newer fluoroquinolones (Levofloxacin, gatifloxacin, moxifloxacin)
56
When should you consider Vancomycin?
if you suspect MRSA (e.g. nursing home patient or patient in the hospital a long time) - can only be given IV
57
What is impetigo?
superficial bacterial infection of the skin limited largely to the epidermis and not spreading below the dermal-epidermal junction; described as "weeping," "oozing," "honey-colored," or "draining."; contagious and autoinoculable
58
What causes impetigo?
staphylococcus, sometimes Strep pyogenes (aka GAS)
59
Tx of impetigo?
topical Abx (e.g. mupirocin)
60
Complication of impetigo?
glomerulonephritis
61
What layers of the skin does erysipleas affect?
dermis and epidermis
62
What causes erysipleas?
GAS (S. pyogenes)
63
Presentation of erysipelas?
bright red, angry, swollen appearance to face +/- F/C, bacteremia
64
Tx of erysipelas?
- Dicloxacillin, cephalexin (Keflex), or cefadroxil (Duricef)
- IV equivalent = oxacillin/nafcillin, cefazolin
- If culture confirms Streptococcus --> PCN G or ampicillin
65
What is cellulitis?
Bacterial infection of the dermis and subQ tissues with Staph and Strep
66
Tx of cellulitis?
- Dicloxacillin, cephalexin (Keflex), or cefadroxil (Duricef)
- IV equivalent = oxacillin/nafcillin, cefazolin (should be tx if fever, hypotension, signs of sepsis)
67
What are folliculitis, furuncles, and carbuncles?
3 different degrees of severity of Staph infection occurring around a hair follicle (occasionally, Pseudomonas from a hot tub)
68
Tx of folliculitis?
topical mupirocin
69
Tx of furuncles and carbuncles?
systemic antistaphylococcal Abx (e.g. Dicloxacillin or cefadroxil)
70
What is necrotizing fasciitis?
extremely severe, life-threatening infection of the skin
71
How does necrotizing fasciitis present?
starts as a cellulitis that dissects into the fascial planes of the skin; v. high fever, portal of entry into the skin, pain out of proportion to the superficial appearance, bullae, palpable crepitus
72
Causative agents of necrotizing fasciitis?
- Type I (DM and PVD pts): S. aureus, B. fragilis, E. coli, GAS, Prevotella
- Type II (healthy w/ h/o trauma to area): GAS
73
Dx of necrotizing fasciitis?
- surgical debridement (also mainstay of tx)
- CPK (up)
- X-ray, CT, or MRI that shows air in the tissue or necrosis
74
Tx of necrotizing fasciitis?
beta lactam/beta lactamase combo medications:
- ampicillin/sulbactam (Unasyn)
- Ticarcillin/clavulanate (Timentin)
- Piperacillin/Tazobactam (Zosyn)
If definitive dx of GAS --> clindamycin and PCN G
75
What is erythema gangenosum?
usu Pseudomonas-caused skin infection following bacteremia, a/w lesion of skin or mucous membranes that evolves into nodular patches marked by hemorrhage, ulceration, necrosis
76
What is paronychia?
infection loculated under the skin surrounding a nail
77
Tx of of paronychia?
small incision to allow drainage; antistaphylococcal abx
78
Tx of HSV?
- PO acyclovir, famciclovir, or valacyclovir (treat empirically if vesicles obvious by exam)
- if acyclovir resistant --> foscarnet
79
Best initial test for HSV when Dx not clear and lesions present?
Tzanck smear
80
Most accurate test for HSV?
viral culture
81
When should VZV be treated?
in immunocompromised child or occurs in an adult
82
Tx of VZV?
acyclovir, valacyclovir, famciclovir
83
Complications of varicella?
PNA, hepatitis, dissemination
84
In whom does shingles (dermatomal herpes zoster) occur more frequently?
-the elderly, those with defects of lymphocytic portion of immune system (e.g. leukemia, lymphoma, HIV, those on steroids)
85
What should be done in a patient with a full VZV infection?
ISOLATE to prevent transmission to susceptible people (and susceptible adults should get VZV IVIG within 96 hours)
86
Complications of full VZV infection?
- bacterial superinfection, PNA, cerebellar ataxia, meningoencephalitis, even DEATH
- congenital varicella syndrome (in newborns of infected moms)
87
What should be done with patients with disseminated herpes zoster?
contact and airborne isolation until all skin lesions are dry and crusted
88
Tx of herpes zoster?
- acyclovir PO (to decrease risk of postherpetic neuralgia)
- TCAs
- topical capsaicin
89
Cause of condyloma acuminata/genital warts?
HPV
90
Tx of condyloma acuminata?
- mechanical removal (cryotherapy, laser removal, trichloroacetic acid, podophyllin [avoid in pregnancy])
- imiquimod (local immunostimulant)
91
How does primary syphilis present?
painless ulceration with heaped-up indurated edges
92
Best initial test for primary syphilis?
darkfield exam (serology not sensitive in primary syphilis)
93
Tx of primary and secondary syphilis?
single IM dose of PCN (Doxycycline PO x 2 weeks in PCN-allergic)
94
How does secondary syphilis present?
generalized copper colored maculopapular rash and that is particularly intense on palms and soles, mucous patch, alopecia areata, condylomata lata
95
Dx of secondary syphilis?
RPR, VDRL
96
Dx of scabies?
scraping w/ mineral oil
97
Tx of scabies?
permethrin cream (ivermectin PO in Norweigan scabies)
98
Dx of head lice?
exam under magnification
99
Tx of head/body lice?
permethrin
100
Tx of Lyme if characteristic bulls-eye rash?
empiric tx with oral doxycycline, amoxicillin, cefuroxime
101
Cause of toxic shock syndrome (TSS)?
staphylococcus attached to a foreign body (e.g. tampon, retained sutures)
102
Diagnostic criteria of TSS?
1. fever > 102 F
2. systolic bp < 90
3. desquamative rash
4. vomiting
5. involvement of mucous membranes of eye, mouth, genitals
Also: incr Cr, CPK, LFTs; decr PLT count, CNS dysfxn
103
Tx of TSS?
- vigorous fluid resuscitation
- pressors (e.g. dopamine)
- not clear whether Abx alters course of DZ, but Clinda +/- nafcillin usu given to prevent recurrence
104
Cause of SSSS?
toxin from staphylococcus
105
How does SSSS present?
loss of superficial layers of epidermis in sheets, Nikolsky's sign
106
How is SSSS different from TSS?
SSSS presents with normal blood pressure and no involvement of liver, kidney, bone marrow, CNS
107
How is SSSS different from TEN?
SSSS is not a full thickness split of skin
108
Tx of SSSS?
mgmt in burn unit; oxacillin/nafcillin or other antistaph meds
109
What part of the body does anthrax affect?
skin - causes papules that later become inflamed and develop central necrosis (black)
110
How is anthrax acquired?
livestock
111
Dx of anthrax?
culture and gram stain of lesion
112
Tx of anthrax?
Ciprofloxacin or doxycycline
113
Dx and Tx of melanoma?
excision; IFN seems to reduce rate of recurrence
114
Most important prognostic factor of melanoma?
depth (Breslow thickness)
115
What is seborrheic keratosis?
benign condition of the elderly - hyperpigmented lesions with "stuck on" appearance, most common on face
116
Tx of seborrheic keratosis?
liquid nitrogen or curettage ONLY FOR COSMETIC PURPOSES
117
What is actinic keratosis?
precancerous lesions occurring on sun-exposed areas of body in older persons
118
Tx of actinic keratosis?
sunscreen, removal with cryotherapy, topical 5 fluorouracil, imiquimod, topical retinoid acid derivatives, or even curettage
119
Tx of SCC?
surgical removal; alternative (if pt cannot undergo removal) --> radiation
120
Tx of BCC?
surgical removal; Mohs surgery has greatest cure rate
121
What is Kaposi's sarcoma? What is the cause?
purplish lesions found on skin predominantly of patients with HIV and CD4 counts < 100; HHV8 virus
122
Tx of Kaposi's sarcoma?
start HAART to raise CD4 count; in pts whom this does not occur --> liposomal Adriamycin & vinblastine
123
Tx of psoriasis?
- all patients should use emollients
- salicylic acid used to removed heaped up scaly material so other therapies can make contact
- if localized --> topical steroids (can sub Vit A [e.g. tazarotene] or D [calcipotriene] derivatives to avoid atrophy)
- if severe --> add coal tar or anthralin derivatives; MTX can be considered but causes liver fibrosis
- when >30% of body affected, consider UV light
- newest therapies: immunomodulatory biologic agents (e.g. alefacept, efalizumab, etanercept, infliximab)
124
How does atopic dermatitis present?
high IgE levels, red itchy plaques on flexor surfaces
125
Prevention of atopic dermatitis?
emollients, avoid hot water and drying soaps, use only cotton clothes
126
Tx of active atopic dermatitis?
topical steroids, antihistamines, coal tars, phototherapy, antistaphylococcal abx if impetiginization of skin, topical immunosuppressants (e.g. tacrolimus & pimecrolimus), doxepin (tricyclic) to help stop pruritus
127
Cause of seborrheic dermatitis?
oversecretion of sebaceous material + HSR to a superficial fungal organism Pityrosporum ovale
128
Tx of seborrheic dermatitis?
- low potency topical steroids e.g. hydrocortisone
- topical antifungal e.g. ketoconazole or selenium sulfide
- zinc pyrithione shampoo
129
What is stasis dermatitis?
buildup of hemosiderin in tissue over long time from venous incompetence in lower extremities;
130
Tx of stasis dermatitis?
irreversible, but can prevent progression with elevation of legs and lower extremity support hose
131
What causes contact dermatitis?
HSR to soaps, detergents, latex, jewelry, sunscreen, or neomycin over area of contact
132
Dx of contact dermatitis?
patch testing
133
Tx of contact dermatitis?
ID causative agent, antihistamines, topical steroids
134
What is the presentation of pityriasis rosea?
pruritic eruption that begins with a "herald patch" 70-80% of the time, is erythematous and salmon-colored and looks like secondary syphilis, except it spares palms and soles, has a herald patch, and VDRL/RPR is negative. Lesions on the back appear like a Christmas tree pattern.
135
Px of pityriasis rosea?
mild, self-limited, usu resolves in 8 weeks without scarring
136
Tx of pityriasis rosea?
usu self-ltd, but lesions that are very itchy may be treated with topical steroids
137
Contributing organism of acne?
propionibacterium acnes
138
How is mild acne treated?
topical retinoid
139
How is moderate acne or mild refractory acne treated?
1. topical retinoid, benzoyl peroxide, topical Abx (e.g. clindamycin, erythromycin)
OR
2. systemic Abx + topical retinoid OR benzoyl peroxide
140
How is severe cystic acne treated?
1. Start with systemic Abx + topical retinoid OR benzoyl peroxide
2. if no response after 3-6 mo, add isoretinoin PO
141
Presentation of alopecia areata?
smooth discrete areas of complete hair loss with no associated scarring, scaling, inflammation.
142
Px of alopecia areata?
most people have regrowth over time, but there is a high chance of recurrence
143
Tx of alopecia areata?
topical or intralesional steroids
144
Presentation of discoid lupus?
scaling, inflammation, scarring, hypopigmentation
145
What is androgenetic alopecia?
male pattern baldness
146
What is the cause of tinea capitis?
Trichophyton tonsurans & microsporum canis (latter visible as green w/ Woods lamp)
147
Tx of tinea pedis?
antifungal cream alone
148
Tx of tinea versicolor?
topical ketoconazole
149
Most common cause of cause of onychomycosis?
Trichophyton rubrum
150
Presentation of photoaging?
coarse deep wrinkles on rough skin surface, actinic keratoses, telangiectasias, and brown ("liver") spots
151
What is the cause of photoaging?
UV light
152
What exacerbates photoaging?
smoking
153
Tx of photoaging?
ATRA/tretinoin (emollient)
154
What exacerbates rosacea?
alcohol, emotions
155
Tx of rosacea?
metronidazole
156
What is presentation of lichen planus?
multiple discrete intensely pruritic polygonal violaceous papules/plaques involving the flexural surfaces of extremities (commonly wrists), buccal mucosa, or external genitalia
157
Dx of lichen planus?
often clinical but skin bx may be needed
158
What other condition is lichen planus associated with?
hepatitis C (do serology!)
159
Tx of keloids?
intralesional steroids
160
SFX of Doxycycline (for acne)?
phototoxicity
161
SFX of minocycline (for acne)?
tooth discoloration, vertigo, pseudotumor cerebri, lupus-like syndrome
162
SFX of clindamycin (for acne)?
rash, urticaria, SJS
163
SFX of isotretinoin (for acne)?
hypertriglyceridemia (get TGs, serum cholesterol, LFTs routinely) & related acute pancreatitis, myalgias, hyperostosis, pseudotumor cerebri, night vision abnormalities, bone marrow suppression, hepatotoxicity; also, oral retinoic acid derivatives are strong teratogens (alternatives = azeleic acid, Clindamycin, erythromycin)
