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aka - Dilantin Hypersensitivity syndrome or Phenytoin Hypersensitivity Syndrome
aka DRESS (drug rash with eosinophilia and systemic symptoms)
| • | a systemic reaction characterized by fever, facial edema, lymphadenopathy, sore throat |
| • | rash of variable morphology (morbilliform to TEN); eventually becomes purpuric |
| • | 2 to 6 weeks after initiation of therapy |
| • | labs: increased LFT’s, striking eosinophilia, atypical lymphocytes |
| • | resolves rapidly with drug cessation |
| • | systemic steroids may help skin, but unclear if it affects systemic symptoms |
pathogenesis:
| • | occurs on first exposure; problem with detoxification of drug |
| • | inherited deficiency of enzyme epoxide hydrolase |
| • | genetic; first degree relatives often with same problem |
Most common:
| • | patients who react to one sulfonamide antibiotic are at increased risk to react to others |
| • | do not appear to be at increased risk to some sulfonamide derivatives such as oral hypoglycemics or diuretics |
| • | however, they are at risk with other aromatic amines, including: dapsone, salazopyrine, and other types of procainamide |
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| • | phenytoin, phenobarbital, carbamazepine |
| • | react with one then high likelihood (70-80%) to react to another (gabapentin and tricyclics might also cross react) |
| • | valproic acid is usually considered a safe alternative |
| • | lamotrigine (Lamictal) = structurally dissimilar drug; hypersensitivity syndrome has been reported |
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DRESS:
manifestations that vary by drug:
anticonvulsants:
| • | classic facial edema, eosiniphilia, elevated LFT's |
allopurinol:
minocycline:
| • | more pulmonary involvement |
dapsone:
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