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Dermatology USMLE Step 3 > Section 1: Bullous and Blistering Diseases > Flashcards

Section 1: Bullous and Blistering Diseases Flashcards

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1
Q

Pemphigus Vulgaris:

This is an autoimmune disease of unclear etiology in which the body becomes, essentially, allergic to its own skin. Antibodies are produced against antigens in the intercellular spaces of the epidermal cells

List the causes of pemphigus vulagaris

A
  • Idiopathic
  • ACE inhibitors
  • Penicillamine

Pemphigus vulgaris acts like a burn, because the bullae occur from destruction within the epidermis and so are relatively thin and fragile

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8594-8602). Kaplan Publishing. Kindle Edition.

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2
Q

Nikolsky’s sign

Nikolsky’s sign is the easy removal of skin by just a little pressure, with the examiner’s finger pulling it off like a sheet.

List the conditions in which Nikolsky’s sign is seen

A
  • Pemphigus vulgaris
  • Staphylococcus scalded skin (SSS) syndrome
  • Toxic epidermal necrolysis

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8594-8602). Kaplan Publishing. Kindle Edition.

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3
Q

True or False:

Pemphigus vulgaris is pruritic

A

False. The lesions are painful; not pruritic

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4
Q

Pemphigus vulagaris

  1. Most accurate diagnostic test
  2. Best initial Rx
  3. Rx when (2) fails
A
  1. Skin biopsy
  2. Glucocorticoids (prednisone)
  3. When steroids are ineffective:
    • Azathiaprine
    • Mecophenolate
    • Cyclophosphamide
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5
Q

Bullous Pemphigoid

** Pemphigoid can be drug induced by sulfa drugs and others**. The fracture of the skin causing the blisters is relatively deep, and the bullae are thicker walled and much less likely to rupture than the bullae of pemphigus vulgaris. Oral lesions are rare. Because the bullae are tense and intact, the skin is better protected. There is no dressing for skin as good as the skin. Hence, there is much less fluid loss and infection is much less likely as compared with pemphigus vulgaris.

  1. Diagnostic test
  2. Best initial Rx
  3. Alternative to (2) above
A
  1. Biopsy with immunofluorescent antibodies
  2. Systemic steroids, such as prednisone
  3. Alternatives to steroids
    • Tetracycline
    • Erythromycin with nicotinamide

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8614-8627). Kaplan Publishing. Kindle Edition.

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6
Q

True or False:

  1. Oral lesions are common in Bullous Pemphigoid
  2. Mortality is much less likely in bullous pemphigoid
  3. Pemphigoid can be drug induced by sulfa drugs and others
A
  1. False, they are rare
  2. True
  3. True

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8614-8627). Kaplan Publishing. Kindle Edition.

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7
Q

Compare Pemphigus vulagris (PV) with Bullous Pemphigus (BP)

A
  1. Age range for PV is 30s anf 40s WHILE age range for BP is 70s and 80s
  2. PV is lifethreatening but BP resolves
  3. Bullae are thin and fragile in PV BUT are thick and intact in BP
  4. The mouth is involved in PV BUT not so in BP
  5. Nikolsky’s sign is positive in PV; it is not present in BP
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8
Q

Pemphigus Foliaceus

  1. What is it associated with?
  2. Diagnostic tests?
  3. Rx?
A
  1. This blistering disease is associated with
    • Other autoimmune diseases
    • Drug induced by ACE inhibitors or NSAIDs.
  2. Biopsy
  3. Treated with steroids in the same fashion as pemphigus vulgaris.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8651-8659). Kaplan Publishing. Kindle Edition.

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9
Q

True or False (Pemphigus Foliaceus):

  1. Foliaceus is much more superficial than pemphigus vulgaris and bullous pemphigoid, and intact bullae are not seen because they break so easily
  2. There are no oral lesions.
A
  1. True
  2. True

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8651-8659). Kaplan Publishing. Kindle Edition.

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10
Q

Porphyria Cutanea Tarda (PCT)

This is a disorder of porphyrin metabolism resulting in a photosensitivity reaction to an abnormally high accumulation of porphyrins

List the conditions associated with PCT

A
  • Alcoholism
  • Liver disease
  • Chronic hepatitis C
  • Oral contraceptives
  • Liver disease, such as chronic hepatitis or hemochromatosis PCT, is associated with increased liver iron stores
  • Diabetes is found in 25 percent of patients

Use the mnemonic “CH LOAD”

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8661-8665). Kaplan Publishing. Kindle Edition.

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11
Q

CF of PCT

A
  • Nonhealing blisters on the sun-exposed parts of the body, such as the backs of the hands and the face
  • Hyperpigmentation of the skin
  • Hypertrichosis of the face

Hypertrichosis is excess hair

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8661-8665). Kaplan Publishing. Kindle Edition.

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12
Q

PCT

  1. Diagnostic test
  2. Rx
A
  1. Urinary uroporphyrins
  2. Manage as follows:
    • Stop drinking alcohol
    • Stop all estrogen use
    • Use barrier sun protection
    • Use phlebotomy to remove iron. Deferoxamine is used to remove iron if phlebotomy is not possible
    • Chloroquine increases the excretion of porphyrins
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13
Q

Urticaria

Acute urticaria is a hypersensitivity reaction, most often mediated by IgE and mast cell activation, which results in evanescent wheals and hives. It is a type of localized, cutaneous anaphylaxis but without hypotension and hemodynamic instability. The onset of the wheals and hives is usually within 30 minutes and lasts for < 24 hours. Itching is prominent

List the causes of acute urticaria

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8676-8681). Kaplan Publishing. Kindle Edition.

A
  1. Medications (aspirin, NSAIDs, morphine, codeine, penicillins, phenytoin, and quinolones)
  2. Insect bites
  3. Foods (peanuts, shellfish, tomatoes, and strawberries)
  4. Emotions (occasionally)
  5. Contact with latex (in any form)

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8682-8692). Kaplan Publishing. Kindle Edition.

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14
Q

List the factors associated with chronic urticaria

A

Pressure on the skin: Pressure on the skin resulting in localized urticaria is also known as dermatographism

Cold

Vibration

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8682-8692). Kaplan Publishing. Kindle Edition.

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15
Q

Rx of severe acute urticaria

Rx of life threatening reactions

A

H1 antihistamines: Severe, acute urticaria is treated with older medications

  • Diphenhydramine (Benadryl)
  • Hydroxyzine (atarax)
  • Cyproheptadine

For lifethreatening reactions

  • Add systemic steroids to above Rx

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8682-8692). Kaplan Publishing. Kindle Edition.

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16
Q

Rx of chronic urticaria

A

Newer, nonsedating antihistamines

  • Loratadine
  • Desloratadine
  • Fexofenadine
  • Cetirizine
17
Q

When is desensitization the right thing to do in the Rx of urticaria?

What medications should be stopped before desensitization?

A

When the trigger cannot be avoided

  • An example of this is a bee sting in a person who is a farmer

Beta blocker medications must be stopped prior to desensitization, because they inhibit the epinephrine that may be used if there is an anaphylactic reaction.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8696-8699). Kaplan Publishing. Kindle Edition.

18
Q

Morbilliform rash is a milder version of a hypersensitivity reaction than urticaria. This is the “typical” type of drug reaction and is usually secondary to medications to which the patient is allergic, such as penicillin, sulfa, allopurinol, or phenytoin. The rash resembles measles; it is a generalized maculopapular eruption that blanches with pressure. The reaction can appear a few days after the exposure and may begin even after the medication has been stopped.

  1. Pathogenesis
  2. Rx
  3. Place of steroids
A
  1. Morbilliform rash is lymphocyte mediated
  2. Antihistamines
  3. Steroids are rarely necessary

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8700-8714). Kaplan Publishing. Kindle Edition.

19
Q

List the causes of erythema multiform

A
  • Penicillins
  • Phenytoin
  • NSAIDs
  • Sulfa drugs
  • Infection with herpes simplex or mycoplasma

This condition presents with targetlike lesions that especially occur on the palms and soles. These lesions can also be described as “irislike.” Bullae are not uniformly found. EM of this type usually does not involve mucous

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8700-8714). Kaplan Publishing. Kindle Edition.

20
Q

Rx of erythema multiform (EM)

A

Antihistamines and the underlying infection

21
Q

Stevens-Johnson Syndrome (SJS)

An hypersensitivity response to medications. List them.

A

Penicillins

Sulfa drugs

NSAIDs

Phenytoin

Phenobarbital

22
Q

SJS

  1. Percent of total body surface area
  2. Percent overall mortality
A
  1. <10-15
  2. <5-10
23
Q

SJS

  1. There is mucous membrane involvement. List the common parts of the body involved.
  2. True or false: The respiratory tract can be involved
  3. In what unit are these patients managed
  4. Common cause of death
  5. Place of steroids
A
  1. Oral cavity and conjunctiva
  2. True. May require mechanical ventilation
  3. In the burn unit
  4. A combination of infection, dehydration, and malnutrition
  5. No. IVIG, cyclophosphamide, and thalidomide do not have nay clear value
24
Q

Toxic epidermal necrolysis (TEN)

TEN is the most serious version of cutaneous hypersensitivity reaction

  1. Percent BSA involved
  2. Mortality percent
  3. True or False: Nikolsky’s sign is present
  4. Most common cause of death
  5. There is a place for prophylactic systemic antibiotics
  6. Diagnostic test
  7. Rx
  8. Place of steroids in Rx
A
  1. 30 – 100 percent
  2. 40– 50 percent
  3. True
  4. Sepsis
  5. Not indicated
  6. Skin biopsy
  7. Supportive
  8. Systemic steroids are not an effective treatment and may, in fact, decrease chances of survival.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8730-8738). Kaplan Publishing. Kindle Edition.

25
Q

Fixed drug reaction

This is a localized allergic drug reaction that recurs at precisely the same anatomic site on the skin with repeated drug exposure. Fixed drug reactions are generally round, sharply demarcated lesions that leave a hyperpigmented spot at the site after they resolve.

Rx?

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8740-8749). Kaplan Publishing. Kindle Edition.

A

Topical steroids

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8740-8749). Kaplan Publishing. Kindle Edition

26
Q

Diagnosis:

  • Painful, red, raised nodules appear on the anterior surface of the lower extremities
  • Nodules are tender to palpation
  • Nodules do not ulcerate
  • Nodules last about 6 weeks.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8740-8749). Kaplan Publishing. Kindle Edition.

A

Erythema nodosum

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8740-8749). Kaplan Publishing. Kindle Edition.

27
Q

Erythema nodosum (EN)

Erythema nodosum is usually secondary to recent infections or inflammatory conditions

List the causes of EN

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8748-8757). Kaplan Publishing. Kindle Edition.

A
  • Pregnancy
  • Recent streptococcal infection
  • Coccidioidomycosis
  • Histoplasmosis
  • Sarcoidosis
  • Inflammatory bowel disease
  • Syphilis
  • Hepatitis
  • Enteric infections, such as Yersinia Treatment is with analgesics and NSAIDs and by treating the underlying disease.

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8748-8757). Kaplan Publishing. Kindle Edition.

28
Q

Rx of erythema nodosum

A

Analgesics and NSAIDs

Treating the underlying disease

Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kaplan Medical Usmle Master the Boards Step 3) (Kindle Locations 8748-8757). Kaplan Publishing. Kindle Edition.

29
Q

Rx of vitiligo

A

Corticosteroids and phototherapy

30
Q

Diagnosis

  • Described by the patient as “Bulle-eye” lesions on both palms +- tenderness
  • Occurs intermittently but worse in the Spring or Fall
  • PE: Erythematous macules surrounding an edematous ring with a central dusky center on both palms

How is the above condition managed?

A

Erythema mulriforme minor (Herpes-associated erythema multiforme). This condition typically occurs 1-3 weeks after an outbreak of herpes labialis, less commonly genital herpes. Often the herpes outbreak will go unrecognized by the patient and the lesions are generally resolved by the time the erythema multiforme is evident

Long term suppression of HSV with acyclovir decreases or elimates recurrence of erythema multiforme minor

Dermatology USMLE Step 3 (4 decks)

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