Internal Medicine

0521779407-21 CUNY1086/Karliner 0 521 77940 7 June 7, 2007 18:59

Urticaria (Rheumatology) 1499

■Chronic: >10 weeks

➣40% urticaria alone

➣40% urticaria & angioedema

➣20% angioedema alone

Chronic

■Most are idiopathic, have no association

■Duration of lesions

➣Individual hives last <2 hrs: consider physical urticaria

➣Individual hives last >2 hrs: any other cause

■Physical Urticaria

➣Linear hives lasting <2 hrs w/ generalized pruritus=dermato-

graphism

➣Hives w/ exercise, hot showers, acute anxiety=cholinergic

urticaria

➣Hives along belt line, tight garments, foot swelling or hives when

walking & hives on buttocks with sitting=pressure urticaria

➣Hives touching cold objects, wind blowing in face, lip swelling

eating ice cream=cold urticaria

➣Hives w/ exposure to sun=solar urticaria. If only outdoors, due

to UV wavelengths. If indoors also, visible light wavelengths

➣Hives touching warm/hot objects=local heat urticaria

➣Swelling when rubbing with towel=vibratory angioedema

■Angioedema typically lasts 1–3 days

tests

Acute Urticaria/Angioedema

■CBC, ESR

■Food skin tests

■Penicillin skin testing and/or RAST assay, if suspect

■Liver function tests or EB viral titer if either hepatitis or infectious

mononucleosis suspected

Physical Urticaria

■Hives w/ scratch: dermatographism

■Hives w/ ice cube applied to forearm for 5 minutes; cold urticaria;

obtain cold agglutinin titer & check for cryoglobulins

■Hives after running in place or on treadmill for 15 minutes: cholin-

ergic urticaria

■Hives after application of test tube containing hot water to forearm

for 5 minutes: local heat urticaria

■Weighted carrying case with strap over shoulder for 15 minutes; hives

on shoulder 4–8 hrs later: pressure urticaria