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Drug Eruptions

»	A patient presents to your office with a 10-page typed out medical history. She states that she is “allergic” to twenty different medicines. Is she likely to have drug allergies or drug intolerances to most of these drugs?
»	Name some nonimmunologic drug reactions.
»	What is the most common manifestation of an adverse drug reaction?
»	How does a cutaneous drug eruption typically present?
»	How should a suspected drug reaction be evaluated?
»	Which commonly used drugs are most likely to produce a cutaneous reaction?
»	Can preexisting diseases enhance the chance of getting a maculopapular skin eruption when using amoxicillin or ampicillin?
»	What infectious disease increases the chance of a cutaneous adverse reaction to trimethoprim-sulfamethoxazole?
»	Which feared drug eruption results in sloughing of the entire skin surface and mucous membranes?
»	Why do some patients get toxic epidermal necrolysis?
»	What is the difference between erythema multiforme major, Stevens-Johnson syndrome, and toxic epidermal necrolysis?
»	What drugs are typically associated with Stevens-Johnson syndrome?
»	Which type of drug reaction can result in a quick death?
»	What class of drugs is the most common cause of anaphylaxis?
»	Name the drugs most likely to induce urticaria.
»	How is drug-induced urticaria mediated?
»	A 45-year-old white man comes to the emergency room with large areas of nonpitting edema over the face, eyelids, neck, tongue, and mucous membranes, which developed 6 hours ago. Ten days earlier, he started a new drug for hypertension. What is the most likely cause of his reaction?
»	A patient is evaluated for a several-day history of fever, malaise, urticaria, arthralgias, lymphadenopathy, and a peculiar erythema along the sides of his palms and soles. He has been started on several new medications in the last few weeks. What is the most likely diagnosis?
»	A man complains of a recurrent burning eruption on his penis. He develops a single blister over the glans penis that heals over 1 to 2 weeks with hyperpigmentation. This same pattern has happened on three occasions in the last 2 years. What does he have?
»	How does drug-induced lupus erythematosus (LE) differ from idiopathic systemic lupus erythematosus (SLE)?
»	What drugs are usually associated with drug-induced LE?
»	Which drug is usually associated with erythema nodosum?
»	What drugs are associated with lichenoid drug eruptions?
»	Name the drugs most likely to produce cutaneous hyperpigmentation and discoloration.
»	What drugs can produce subepidermal bullae and erosions on the dorsum of the hands?
»	Name two drugs that commonly exacerbate porphyria cutanea tarda.
»	A 30-year-old white woman is evaluated with a new case of “acne.” Over the last few days, she has suddenly developed erythematous follicular papules and pustules over her upper trunk. She was admitted 3 weeks earlier with an acute exacerbation of SLE that is now improving. What is the most likely diagnosis?
»	A middle-aged man who is a dialysis patient presents to your clinic with a “woody” appearance to his legs. He had an MRI with gadolinum-containing contrast a few months prior. What might he be suffering from?
»	Describe a typical presentation of warfarin necrosis.
»	Name and describe the two types of photoinduced drug eruptions.
»	What drugs commonly cause phototoxic drug reactions?
»	What drugs commonly cause photoallergic drug reactions?
»	What is AGEP? How does it present?
»	You have been treating a patient for severe, scarring acne with an oral medication for the last three months. Her acne looks great but now she is starting to lose hair. What drug are you most likely using?

Name some nonimmunologic drug reactions.

Nonimmunologic activation of effector pathways, such as direct release of histamine from mast cells and basophils by aspirin, nonsteroidal antiinflammatory drugs (NSAIDs), opiates, polymyxin B, d-tubocurarine, and radiocontrast media
Overdosage
Cumulative toxicity, such as the accumulation of drugs or metabolites in the skin (e.g., argyria with the use of silver nitrate spray)
Normal pharmacologic effects of the drug that are not the primary therapeutic objective (e.g., alopecia following chemotherapy)
Drug interactions (e.g., administration of ketoconazole may lead to higher levels of cyclosporine and increased toxicity)
Metabolic changes, such as warfarin producing a hypercoagulable state that results in warfarin necrosis
Exacerbation of preexisting dermatologic diseases (e.g., lithium can exacerbate acne, psoriasis, and subcorneal pustular dermatosis)
Ecologic changes, such as antibiotics that reduce the bacteriologic flora, predisposing the patient to candidal infections
Inherited enzyme or protein deficiencies (e.g., the phenytoin hypersensitivity syndrome occurs in patients deficient in epoxide hydrolase, an enzyme required for metabolism of a toxic epoxide derived from phenytoin)
Jarisch-Herxheimer phenomenon secondary to bacterial endotoxins and microbial antigens that are liberated from antimicrobial treatment (e.g., a patient with syphilis develops fever, tender lymphadenopathy, arthralgias, and urticaria while being treated with penicillin)

Stern RS, Wintroub BU: Cutaneous reactions to drugs. In Freedberg IM, Eisen AZ, Wolff K, editors: Fitzpatrick’s dermatology in general medicine, ed 5, New York, 1999, McGraw-Hill, pp 1633–1642.