Pharmacology
Pharmacology
Core54: Drug-induced adverse reaction: Stevens-Johnson syndrome
薬剤性有害反応：スティーブンス・ジョンソン症候群
🚨 High-yield / 要点：Stevens-Johnson syndrome is a rare, severe T-cell mediated type IV hypersensitivity skin/mucosal reaction. SJS <10% skin, TEN >30% skin.
Definition / 定義
- Stevens-Johnson syndrome / SJS = rare, very serious skin and mucous membrane reaction, usually drug-triggered.
- Mechanism:
- Abnormal immune response to drugs.
- Type IV delayed T-cell mediated hypersensitivity.
- Autoimmune tissue reaction.
- Genetic predisposition:
- Some HLA variants increase risk.
SJS vs TEN / SJSとTEN
| Condition | Skin involvement | Severity |
|---|---|---|
| SJS | ~10% or less | Severe; mortality about 7.5% |
| TEN / toxic epidermal necrolysis | >30% | More severe autoimmune reaction |
Symptoms / 症状
- Body rash.
- Flu-like symptoms.
- Mucosal desquamation.
- Bullae.
- Painful inflammation of mouth and tongue.
- Conjunctivitis.
- Extensive skin peeling.
Drugs causing SJS / 原因薬
| Drug group | Examples |
|---|---|
| Antibiotics | Sulfamethoxazole-trimethoprim, penicillin, cephalosporins such as cefixime, nevirapine |
| Antiepileptics | Lamotrigine, phenytoin, ethosuximide, carbamazepine |
| NSAIDs / anti-gout drugs | Phenylbutazone, diclofenac, ibuprofen, allopurinol |
Treatment / 治療
- Medical emergency.
- Requires intensive care unit management.
- Stop the causative drug immediately.
- Supportive care for skin, mucosa, fluids, infection risk, and organ complications.
Remember / 覚え方
- SJS/TEN = severe mucocutaneous drug reaction
- TMP-SMX, antiepileptics, NSAIDs, allopurinol are high-yield triggers
- Lamotrigine needs slow titration
- Carbamazepine has genetic predisposition risk