Emergency Medicine Q & A, 2009, Pg

Emergency Medicine Q & A, 2009, Pg


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esterase. She also
has symptoms of a mild upper respiratory infection, but is otherwise healthy and has no known allergies.
You give her a prescription for ampicillin, but she returns 2 days later with a diffuse, nonpruritic rash over
her abdomen and trunk. She is otherwise asymptomatic. You should now:
a. Advise her to continue the antibiotic because the rash does not itch.
b. Advise her to take diphenhydramine, 25 mg every 6 hours, and continue the ampicillin.
c. Inform her that ampicillin interacts with viral URIs, and to continue the ampicillin.
d. Discontinue the ampicillin and prescribe trimethoprim-sulfamethoxazole.
e. Discontinue the ampicillin and prescribe cefaclor.
The answer is d. Many drug eruptions can appear like viral exanthems. Ampicillin can cause skin rashes,
particularly in patients with infectious mononucleosis. If a rash develops when taking a drug, the drug should be
stopped and an appropriate alternative prescribed because continued administration can lead to erythroderma or
exfoliative dermatitis. Although cefaclor is not contraindicated in this setting, it is expensive. Trimethoprim-
sulfamethoxazole would be the best choice with the understanding that cutaneous reactions with this medication
are not uncommon.
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64 Emergency Medicine Q & A: Pearls of Wisdom ...
3. In patients with suspected Stevens-Johnson syndrome:
a. Oral lesions are common but rarely become secondarily infected.
b. Ocular involvement is exceedingly rare.
c. It often is complicated by thrombophlebitis.
d. Women may complain of vulvovaginitis.
e. Discomfort may be severe but fatalities are virtually unheard of.
The answer is d. The Stevens-Johnson syndrome is a severe form of erythema multiforme characterized by
generalized bullae that involve the skin and mucous membranes, including the mouth, vagina, eyes, and esophagus.
Dehydration results from painful stomatitis and weeping skin surfaces. Secondary infections of the denuded
epithelium are common, as are severe ocular complications, including corneal ulcers and blindness.
Thrombophlebitis is not particularly associated with the disease. Steroids provide symptomatic relief. The overall
mortality is 5\u201310%.
4. A 4-year-old girl has had an exudative, encrusting skin eruption on her upper lip and both cheeks for more
than a week. Her mother has applied a 0.5% hydrocortisone cream twice daily, but says the rash is getting
worse. The most likely diagnosis and best treatment is:
a. Acne vulgaris \u2192 treat with tetracycline, 25 mg/kg every 6 hours for 7 days.
b. Impetigo contagiosa \u2192 treat with benzathine penicillin.
c. Bullous impetigo \u2192 treat with dicloxacillin, 50 mg/kg every 6 hours for 10 days.
d. Herpes zoster \u2192 treat with oral acyclovir and initiate immunode\ufb01ciency workup.
e. Nummular eczema \u2192 treat with warm compresses and a more potent topical steroid lotion, such as
\ufb02uocinolone acetonide cream.
The answer is b. Acne does not occur in prepubescents, and tetracycline is contraindicated in children younger
than 8 years. The two types of impetigo require different treatment. Impetigo contagiosa is caused by group A,
beta-hemolytic Streptococcus and progresses from a small red papule to larger, honey-colored crusted lesions.
Treatment should be the same as for a streptococcal infection of the throat, since some strains are nephrotoxic.
Bullous impetigo is caused by phage group II staphylococci and the lesions appear as 0.5\u20133 cm pustular bullae
without erythema. Presumptive treatment with oral antibiotics based on the clinical diagnosis is usually suf\ufb01cient.
Wound cleansing and topical antibiotics are also indicated in both types of impetigo. Eczema may become
secondarily infected (\u201cimpetiginized\u201d), and may be distinguished by the distribution of lesions and clinical history.
Herpes zoster (shingles) is a vesicular eruption following a dermatomal pattern and does not cross the midline.
5. The most common manifestation of Lyme disease is:
a. Erythema migrans.
b. Meningitis.
c. Cognitive impairment.
d. Recurrent arthritis.
e. Heart block
The answer is a. Lyme disease is caused by the spirochete Borrelia burgdorferi. After B. burgdorferi is introduced into
the skin, it spreads locally. The local spread leads to erythema migrans (EM), a rash that is found in approximately
two-thirds of patients. Keep in mind that a rash may not be present in up to 20% of cases and even if present may
be mild, nonspeci\ufb01c, and easily missed by the patient, family, caregivers, and/or the initial treating physicians.
... CHAPTER 4 Cutaneous Emergencies 65
6. In evaluating the skin lesions of patients with AIDS:
a. Kaposi sarcoma is common but seldom more than a cosmetic problem.
b. Candidiasis may occur but is easily treated with standard medications.
c. Tinea corporis is no more likely in these patients than in the general population.
d. Lichen planus of the oral mucosa is associated with the disease.
e. Seborrheic dermatitis-like eruptions are frequently found.
The answer is e. A virulent form of Kaposi sarcoma occurs in patients with AIDS. Recurrent, relatively refractory
infections such as candidiasis and tinea corporis re\ufb02ect the immunode\ufb01ciency state of AIDS. A seborrheic
dermatitis-like eruption has been described in patients with AIDS and is characterized by abrupt onset of a
symmetric, scaling erythematous rash primarily involving the face and chest. Lichen planus is a white lesion of the
oral mucosa with no particular predominance in patients with AIDS (Tintinalli et al., 2003:932).
7. Two weeks ago, a 54-year-old man developed a cold sore, which resolved uneventfully. He now complains of
a nonpruritic skin rash. Examination reveals raised red lesions resembling hives, some with clear \ufb02uid bullae.
They are located on his hands, including the palms, and his forearms and anterior tibia. The best way to
con\ufb01rm your suspected diagnosis is by:
a. Viral culture of blister \ufb02uid.
b. Smear of blister \ufb02uid for Gram stain.
c. Tzanck preparation of blister \ufb02uid to look for multinucleate giant cells.
d. Full thickness skin biopsy of involved area.
e. Wood\u2019s light examination of involved areas.
The answer is d. Herpes simplex infection may precede erythema multiforme (EM). Affected patients may have
recurrent bouts of the disease with each episode of herpes. The virus is not found in the blisters of EM, nor are
fungi or bacteria. Immuno\ufb02uorescent studies of a skin biopsy showing Ig-complement deposits at the
dermoepidermal junction con\ufb01rm the diagnosis. In mild cases, clinical diagnosis and outpatient treatment with
topical steroids and close follow-up are suf\ufb01cient. Other causes, such as drugs and malignancy, should be
considered. Severe cases require hospitalization.
8. Scabies infestations usually spare the:
a. Intertriginous spaces of the hands and feet.
b. Areolar area in females.
c. Penile shaft in males.
d. Pubic area.
e. Scalp.
The answer is e. While scabies infestation may resemble lice infestation, the characteristic distribution of lesions
aids in the differential diagnosis. Scabies bites are usually concentrated about the web spaces of the hands and feet.
In adults, the nipple in females and the penis in males are frequent sites of involvement. Scabies rarely occurs above
the neck in adults, who should be treated from the neck down with topical medications (permethrin, lindane,
crotamiton, or in pregnant women, 5% sulfur ointment). Reapplication may be considered 1 week after initial
treatment. The characteristic burrow of the female mite, a jagged white line with a gray dot at the end and
overlying vesicles, is pathognomonic, but it is often obscured by the effects of scratching and may resemble
dermatitis. Pruritus may persist after treatment and should not be interpreted as a treatment failure; antipruritic
medications are indicated for symptomatic relief. Antibiotics may be indicated for secondary infections.
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