MTB 3 - Dermatology Flashcards
1
Q
How does pemphigus vulgaris present?
A
Painful bullae that are easily ruptured
Involvement of the mouth
Nikolsky’s sign
2
Q
What’s the pathophysiology of pemphigus vulgaris?
A
IgG Antibodies against desmosomes.
Desmosomes allow cell-to-cell adhesion
3
Q
What causes pemphigus vulgaris?
A
Idiopathic
ACE-I
Penicillamine
4
Q
What 3 things can give Nikolsky’s sign?
A
Pemphigus vulgaris
SSSS
Toxic epidermal necrolysis
5
Q
How to diagnose pemphigus vulgaris?
A
Biopsy of skin showing autoantibodies on immunofluorescent studies in a netlike pattern
6
Q
Treatment of pemphigus vulgaris?
A
Prednisone
If inneffective, use azathioprine
Without treatment, this condition is fatal
7
Q
Describe bullous pemphigoid:
A
Much milder disease than pemphigus vulgaris
Bullae stay intact so less fluid loss and infection
Mouth involvement is uncommon
8
Q
Pathophysiology of bullous pemphigoid?
A
IgG antibodies against hemidesmosomes (basement membrane). Linear immunofluorescence.
9
Q
How to diagnose bullous pemphigoid?
A
Skin biopsy showing linear immunofluorescence of IgG against the hemidesmosomes of the basement membrane
10
Q
Treatment for bullous pemphigoid?
A
Prednisone
11
Q
What ages does pemphigus vulgaris and bullous pemphigoid present?
A
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
12
Q
What is porphyria cutanea tarda (PCT)?
A
Disorder of porphyrin metabolism –>
High accumulation of porphyrins –>
Causes photosensitivity reaction
13
Q
List 5 associations with PCT:
A
Alcoholism Liver disease -Chronic Hep C -Hemochromatosis OCP Diabetes
14
Q
How does PCT present?
A
Nonhealing blisters on sun-exposed part of body
Hyperpigmentation of skin
Hypertrichosis of face (excess hair)
15
Q
How to test for PCT?
A
Urinary uroporphyrins will be 2-5x higher than coproporphyrins
16
Q
How to manage PCT?
A
Stop alcohol
Stop estrogen use
Use sun protection
Phlebotomy to remove iron or deferoxamine
Chloroquine increases excretion of porphyrins
17
Q
What is urticaria?
A
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
18
Q
When is the onset of wheals and hives in urticaria? How long does it last?
A
Within 30 minutes of exposure. Lasts for
19
Q
Most common medication causes of urticaria:
A
Aspirin NSAIDs Morphine Codeine Penicillin Phenytoin Quinolones
20
Q
Other common causes of urticaria besides medications:
A
Insect bites
Foods (peanuts, shellfish, tomatoes, strawberries)
Latex
Emotions (occasionally)
21
Q
Chronic urticaria is associated with:
A
Pressure on skin
Cold
Vibration
22
Q
How to treat urticaria?
A
Always: Antihistamines (diphenhydramine, hydroxyzine, cyproheptadine)
Life-threatening: Systemic steroids
Chronic therapy: Nonsedating antihistamines (loratadine, cetirizine)
23
Q
When do you do desensitization for someone with urticaria?
A
When the trigger can’t be avoided (bee stings in a farmer).
24
Q
What must you stop taking prior to desensitization?
A
Beta-blockers (cause you might need to use epinephrine which uses beta receptors)
25
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
26
Treatment of morbilliform rash?
Antihistamines
27
How does erythema multiforme present?
Targetlike lesions on palms and soles
28
Erythema multiforme is caused by what things?
```
Penicillins
Phenytoin
NSAIDs
Sulfa drugs
HSV or mycoplasms infection
```
29
Treatment of erythema multiforme?
Antihistamines
30
Describe Stevens Johnson Syndrome:
Hypersensitivity reaction
31
Treatment of SJS?
IV immunoglobulin
Cyclophosphamide
*Steroids don't work*
32
What things can cause SJS?
Penicillins
Phenytoin
NSAIDs
Sulfa drugs
33
Describe toxic epidermal necrolysis:
```
Most serious cutaneous hypersensitivity reaction
30-100% BSA
40-50% mortality
Nikoslky's sign
Sepsis most common cause of death
```
34
Should you give prophylactic antibiotics to pts with TEN?
No
35
How to diagnose TEN?
Skin biopsy
36
Treatment of TEN?
Doesn't say
| *Don't give steroids*
37
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*
38
How to treat a fixed drug reaction?
Topical steroids
39
What does erythema nodosum look like?
Painful, red, raised nodules on shins
| Nodules are tender, don't ulcerate, and last 6 weeks
40
Name 9 conditions that cause erythema nodosum:
1. Pregnancy
2. Recent strep infection
3. Coccidioidomycosis
4. Hisoplasmosis
5. Sarcoidosis
6. IBD
7. Syphilis
8. Hepatitis
9. Enteric infections (Yersinia)
41
Treatment of erythema nodosum?
Analgesics and NSAIDs
| Treat underlying disease
42
Best initial test for cutaneous fungal infections:
KOH test of skin (dissolves everything but fungus)
43
Most accurate test for cutaneous fungal infections:
Culture the fungus
44
Treatment for oncyhomycosis (nails) or tinea capitis (hair)?
Oral terbinafine
Oral itraconazole
6 weeks for fingernails - 12 weeks for teonails
45
What is a problem with terbinafine and how do you watch out for it?
Hepatotoxicity
| Check LFTs periodically
46
How does griseofulvin compare to terbinafine?
Not nearly as efficacious. Must use for 6-12 MONTHS
47
All other fungal infections that don't involve hair or nails can be treated with *topical medications*. Name the meds:
Ketoconazole
Econazole
Clotrimazole
Miconazole
48
How does the efficacy of the topical antifungals compare?
No clear difference when used topically
49
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
50
Describe impetigo:
Confined to epidermis
Weeping, oozing, honey-colored
Very contagious
51
What bugs cause impetigo?
```
Staph
Strep pyogenes (Group A)
```
52
Serious complication of impetigo?
Glomerulonephritis
53
Treatment of impetigo?
Topical mupirocen
| If inneffective, use PO oxacillin/nafcillin
54
What layers does eryisepelas effect?
Epidermis and dermis
55
What bug causes erysepelas?
Strep pyogenes (group A)
56
Presentation of eryisepelas?
Fever, chills
| Bright red, swollen appearance to the face
57
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
58
What layers does cellulitis effect?
Dermia and subcutaenous tissues
59
Bugs causing cellulitis?
Staph
| Strep
60
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
61
Treatment of folliculitis?
Topical mupirocen
62
Treatment of furuncles and carbuncles?
Drain carbuncles
| Systemic dicloxacillin or cefadroxil for both
63
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
64
Symptoms of necrotizing fasciitis:
```
Very high fever
Pain out of proportion to appearance
Bullae
Palpable crepitus
Portal of entry in to skin
```
65
What bugs cause necrotizing fasciitis?
Streptococcus
| Clostridia
66
What increases risk of necrotizing fasciitis?
DM
67
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)
68
Treatment for necrotizing fasciitis?
*Surgical debridement is mainstay*
Zosyn
If there's definite Strep pyogenes, tx is clindamycin and penicillin
69
What is paronychia?
Infection in the skin surrounding a nail
70
Treatment of paronychia?
Small incision for drainage +
| Anti-staph drugs (nafcillin/oxacillin)
71
HSV skin infection presentation:
Multiple, painful vesicles
72
How to treat HSV infections?
ORAL Acyclovir, famciclovir, or valacyclovir if exam is obvious
Topical does nothing
73
How to treat acyclovir-resistant herpes?
Foscarnet
74
Best initial test for HSV?
Tzanck smear
75
Most accurate test for HSV?
Viral culture (grows in 1-2 days)
76
Complications of varicella in kids?
Pneumonia
Hepatitis
Dissemination
77
Treatment of shingles?
Acyclovir to reduce risk of postherpetic pain
Steroids for elderly pts with severe pain
For postherpetic pain: Gabapentin
78
How does HPV present?
White or flesh-colored, translucent heaped-up lesions
79
Another term for HPV lesions?
Condylomata acuminata
80
Diagnostic testing for Condylomata acuminata?
No form of testing is routinely necessary
81
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
```
82
How does primary syphilis present:
Chancre = Ulceration with heaped-up indurated edges. Painless
83
Best initial test for primary syphilis?
*Darkfield exam* (not VDRL/RPR due to 25% false neg rate)
84
How to treat primary or secondary syphilis?
Single IM dose of penicillin
| Doxycycline if allergic
85
How does secondary syphilis present?
Generalized copper-colored, maculopapular rash, especially on *palms and soles*
86
Best initial test for secondary syphilis?
VDRL and RPR (100% sensitivity)
87
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
88
Where does scabies spare?
Head
89
How to test for scabies?
Scraping out organism after mineral oil is applied to a burrow
90
Treatment of scabies?
Permethrin
91
What is pediculosis?
Lice and crabs
92
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)
93
How to diagnose pediculosis?
Viewing the organism on the hair under magnification
94
Treatment of pediculosis?
Permethrin
95
The rash of lyme disease occurs how long after the bite?
7-10 days
96
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
97
How to treat Lyme disease?
PO Doxycycline or amoxicillin
98
What will happen if you don't treat lyme disease?
66% develop joint disease
| Neurologic or cardiac disorders
99
What causes toxic shock syndrome?
Staph infection from:
- Nasal packing
- Retained sutures
- Tampons
100
How to diagnose toxic shock syndrome?
Must have:
- Fever >102
- Systolic
101
What can be found on labs with toxic shock syndrome?
High creatinine, CPK, LFTs
Low platelet count
CNS dysfunction (confusion)
102
How to treat toxic shock syndrome?
Fluid resuscitation
Pressors (dopamine)
Oxacillin/nafcillin
Vanc or linezolid for MRSA
103
How is SSSS different from TSS?
It has normal BP and doesn't affect liver, CNS, etc
104
Which layers of skin does SSSS affect?
Only the superficial granular layer
105
Management of SSSS?
Admit to burn unit
| Give oxacillin/nafcillin
106
How is anthrax usually acquired?
From infected livestock
| -Occupational hazard of wool sorters
107
How does an anthrax infection present?
Cutaneous infection
| -Inflamed papule that develops black central necrosis
108
What does anthrax mean in Greek?
*Coal*
109
Hwo to diagnose anthrax?
Gram stain and culture of lesion
110
Treatment of anthrax?
Ciprofloxacin or doxycycline
111
Describe melanoma
```
Malignant
Grow in size
Irregular borders
Uneven shape
Inconsistent coloring
```
112
Most prognostic factor for skin cancer?
Tumor thickness
113
Tx of melanoma?
Excision
114
Describe seborrheic keratosis
Benign
Hyperpigmented lesions in elderly
*Stuck-on* appearance
Common on face, shoulders, chest, and back
115
Treatment of seborrheic keratosis?
Liquid nitrogen OR curettage
| This would only be done for cosmetic reasons as they are perfectly benign
116
Describe actinic keratosis:
Precancerous
Sun-exposed area of body in older pts
May be tender
117
Treatment of actinic keratosis?
```
Sunscreen to prevent progression/recurrenc
Removed with:
-Cryotherapy
-Topical 5FU
-Imiquimod
```
118
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)
119
Desribe Basal cell carcinoma:
Most common skin cancer
Shiny, *pearly* appearance
Telangiectasias
120
Dx of basal cell?
Shave or punch biopsy
121
Tx of basal cell?
```
Surgical removal
Mohs microsurgery (instant frozen section and stop when margin is clean)
```
122
Describe Kaposi's sarcoma:
Purplish lesions on skin
| Usually in HIV pts with CD4
123
Tx of Kaposi's?
- Start antiretroviral therapy and raise CD4 count
| - Adriamycin and vinblastine (both specific therapy for Kaposi's)
124
Describe psoriasis:
Silvery scales on extensor surfaces
Nail pitting
Can be extensive
125
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
126
Describe atopic dermatitis
Red, itchy plaques
Flexor surfaces
High IgE levels
127
Treatment of atopic dermatitis:
Preventive - emollients and avoid hot water/drying soaps
| Active disease - Topical steroids, antihistamines, phototherapy, avoid scratching
128
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
129
Treatment for seborrheic dermatitis:
- Topical hydrocortisone
- Topical ketoconazole or *selenium sulfide*
- Zinc pyrithione as a shampoo
130
What is stasis dermatitis?
- Hyperpigmentation from built-up hemosiderin
- Occurs from chronic LE-venous insufficiency
- Irreversible
131
Tx of stasis dermatitis?
Prevent progression with elevation of legs + compression
132
Describe contact dermatitis:
- Hypersensitivity to soaps, detergents, latex, jewelry
| - Linear streaked vesicles (esp when from poison ivy)
133
How to definitively diagnose contact dermatitis?
Patch testing
134
Treatment of contact dermatitis?
Antihistamines and topical steroids
135
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)
136
Tx of pityriasis rosea?
Self-limited
Will resolve in 8 weeks
Caused by HSV 6 and 7 (same that cause roseola)
137
Treatment of mild acne:
Topical clindamycin, erythromycin
| Topical retinoids
138
Treatment of moderate acne:
Benzoyl peroxide + retinoids (tazarotene, tretinoin)
139
Tx of severe, cystic acne:
Oral minocycline, tetracycline, clindamycin, isotretinoin
140
What to do before starting an oral retinoic acid derivative?
Pregnancy test
| Make sure pts are on OCPs if female of childbearing age
