Drug Eruptions Flashcards
What is the most common type of cutaneous drug eruption? What is the pattern of spread and when does it start?
Morbilliform drug eruption (looks like measles) -> maculopapular rash
Starts within 1 week of causative drug being started, beginning on head spreading downwards to lower extremities. It clears the same way in 7-14 days.
What drugs are typically implicated in morbilliform drug eruptions?
Penicillins, sulfonamides, barbiturates (i.e. phenobarbital), and seizure medications
What is the most predictable morbilliform drug eruption?
Rash is seen if amoxicillin is given to patient’s with Epstein-Barr virus
What is a fixed drug eruption?
A drug eruption recurring at the same site within hours of a repeated ingestion of a medication
How does a fixed drug eruption appear?
Solitary dusky gray-brown erythematous plaque, may even be bullous
What does AGEP stand for and what usually causes it?
Acute Generalized Exanthematous Pustulosis
Usually due to antibiotics
What does AGEP look like?
Pinpoint superficial pustules on an erythematous base
Begins in intertriginous areas (armpits, groin) and then spreads to whole body. Fever is often present (these patients do not feel good).
What is DRESS syndrome also called and why was the name changed?
Drug Rash with Eosinophilia and Systemic Symptoms
-> Drug-Induced Hypersensitivity Syndrome (DISH, lul) is the new name, since peripheral eosinophilia is not required to make the diagnosis
What are the symptoms of DRESS syndrome?
Exanthem-type morbilliform rash and fever, especially facial edema, with systemic symptoms like hepatitis, interstitial nephritis, arthralgias, lymphadenopathy, or hematologic abnormalities
What drugs are known to cause DRESS syndrome and do they cross-react?
Especially phenytoin, carbamazepine, and phenobarbital
These are three aromatic anticonvulsants which cross react -> if one anticonvulsant causes it so will the others
Lamotrigine doesn’t cross-react with this group
There are some other causes but low yield
If a patient develops DRESS syndrome, what test needs to be run at that time and again in 2-3 months?
Baseline TSH -> a good percentage of these patients will develop hypothyroidism within 2 months of the incident
What is SJS vs TEN?
They are a spectrum of the same disease
SJS: <10% of body surface involved
SJS-TEN: 10-30% of body surface involved
TEN: >30% of body surface involved
What is the pattern of spread of SJS? Does it involve mucosal surfaces?
Prodrome of fever and generally feeling bad
Rash starts on trunk, the spread to face and upper extremities
It ultimately involves the buccal, ocular (including conjunctiva), and genital mucosa in 90% of cases
What do the lesions of SJS/TEN look like / how do they form?
They are flaccid blisters which are formed when the necrotic epidermis detaches from dermis, and edema fluid fills the space
Mucosal eruptions are also very painful, can interfere with vision, voiding, etc
Is Nikolsky’s sign positive or negative in SJS/TEN?
Nikolsky’s sign is positive -> can induce blistering with pressure in affected areas.
Furthermore, Asboe-Hansen sign is positive (blisters extend sideways to dissect laterally)
-> literally these lesions are so tender that a blood pressure cuff could take off the entire epidermis
