0071643192.pdf

DERMATOLOGY

COMPLICATIONS

■ Disruption of dermis can lead to water loss, excessive heat loss, and high-

output CHF due to widespread vasodilatation.

■ Mortality is approximately 30%.

URTICARIA (HIVES)

SYMPTOMS/EXAM

■ Hives are pruritic, erythematous wheals of varying size that are transient,

lasting <24 hours. Urticaria becomes chronic when recurrent eruptions

occur for >6 weeks.

ETIOLOGY

■ Most frequent causes are infection (especially viral), drugs (PCN, sulfon-

amides, NSAIDs, ACE inhibitors), food (shellfish, fish, eggs, nuts), and

idiopathic. Emotional stress, exercise, and excess heat or cold exposure are

also causes.

TREATMENT

■ Avoid cause, supportive treatment includes cold compresses, first- or

second-generation H 1 -receptor blockers. H 2 -receptor blockers and pred-

nisone can be added when chronic or unresponsive to first-line treatment.

Epinephrine when associated with anaphylaxis (ie, hypotension, wheez-

ing, or difficulty breathing).

ERYTHEMA MULTIFORME (EM)

SYMPTOMS/EXAM

■ This erythematous, papular rash appears over 72 hours, most commonly

on hands and forearms (palmar and dorsal surfaces) but also occurs on

feet, face, and lower extremities, usually <10% BSA. There is great varia-

tion, but typically >100 lesions are present.

■ Papules may evolve to target lesionswith a characteristic central dusky or

purple zone surrounded by a pale ring and then third erythematous halo.

■ Discreteoral lesionsare present in ~50% of patients.

DIFFERENTIAL FORRASHESONTHEPALMS

■ EM: Target lesions evolve over 72 hours.

■ Rocky Mountain spotted fever: Erythematous/hemorrhagic macules and

papules

■ Drug eruption: Lesions occur minutes to several hours after drug adminis-

tration. They recur in the same area when the offending drug is given.

They may be circular, violaceous, or edematous plaques that resolve with

macular hyperpigmentation.

■ Secondary syphilis: Scaling papular eruptions

■ Scabies: Papules and burrows, mainly in web spaces, intensely pruritic

■ Hand, foot, and mouth disease: Small, discrete vesicles; patients usually

<10 years old

The standard epinephrine

dose for anaphylaxis is 0.3 mg

IM (usually given as 0.3 mL of

1:1000). Remember 1 mg is a

cardiac arrest dose—don’t give

this much to patients with a

pulse.

Rashes that commonly appear

on the palms: Erythema

multiforme, drug eruption,

secondary syphilis, RMSF,

hand, foot and mouth disease,

scabies.