purpura

(nonblanching purple/red lesions due to extravasation of RBCs into dermis)

• Nonpalpable (macular; ≤3 mm in diameter = petechiae; >3 mm = ecchymoses)

platelet disorder: thrombocytopenia, defect in platelet fxn

thromboemboli: DIC, TTP, cholesterol or fat emboli, other thrombotic microangiopathies trauma or vascular fragility: amyloidosis, Ehlers-Danlos, scurvy

• Palpable (papular); vasculitis: leukocytoclastic, HSP, PAN, RMSF; infectious emboli: meningococcemia, bacterial endocarditis

• Purpura fulminans (aka retiform purpura): purpura + hypotension + DIC; typically due to infxn/sepsis, protein C or S deficiency or APS (see section on DIC)

Explain by ChatGPT

1. Nonblanching purple/red lesions due to extravasation of RBCs into dermis
2. Nonpalpable (macular; ≤3 mm in diameter = petechiae; platelet disorder: thrombocytopenia, defect in platelet function
3. Palpable (papular); vasculitis: leukocytoclastic, HSP, PAN, RMSF; infectious emboli: meningococcemia, bacterial endocarditis
4. Purpura fulminans (aka retiform purpura): purpura + hypotension + DIC; typically due to infection/sepsis, protein C or S deficiency or APS (see section on DIC)

窩的英文不太好

1. 由於紅細胞滲入真皮導致的非變白紫色/紅色病變 2.不可觸及（黃斑；直徑≤3mm=瘀點；血小板異常：血小板減少，血小板功能缺陷
2. 可觸及的（丘疹）；血管炎：白細胞破碎性、HSP、PAN、RMSF；感染性栓子：腦膜炎球菌血症、細菌性心內膜炎
3. 暴發性紫癜（又名網狀紫癜）：紫癜+低血壓+DIC；通常是由於感染/敗血症、蛋白 C 或 S 缺乏或 APS（參見 DIC 部分）