| • | arbitrarily defined as urticaria lasting >6 weeks |
| • | in 50% of cases, angioedema also occurs (differs from hereditary angioedema in that it rarely effects the larynx) |
| • | symptoms continue ≅ 3-5 years (20% will have persistent disease after 20 years) |
etiologies to consider: (infection, physical urticaria, autoimmune)
| • | physical urticarias – check dermatographism and elicit other hx |
| • | infection – parasite (travel history), chronic dental infection (tap on sinuses), H. pylori, hepatitis B,C or D = “urticarial” |
| • | autoimmune/CVD history or symptoms |
"neutrophil rich urticaria"
| • | more severe, recalcitrant |
| • | constitutional symptoms, polyarhtralgias |
| • | treatment: dapsone 50QD (increasing to 100QD if needed) |
How I think of it:
| • | most urticaria "gurus" will tell you that most work-ups for underlying etiologies yield nothing and they help patients by optimizing treatment with anti-histamines |
| • | I have the patient see their internist for a check up with age-appropriate labs and screening tests |
| • | if everything is normal at the internist then I consider their disease to be an autoimmune etiology... |
| • | = histamine releasing IgG autoantibodies vs. FcεRIα (the high affinity IgE receptor of mast cells) |
| • | ≈ 25-45% of chronic idiopathic urticaria (CIU) patients |
Treatment:
| • | Joe Bikowski frequently mentions in his lectures that most anti-histamines are safe at up to four times their normal dose (e.g. you can go up to 40mg of Zyrtec or 40mg of Claritin qd) |
| • | pearl: remind patients that the goal of treatment is to diminish the hives and their symptoms, rather than totally eliminate the hives (that can only be achieved with the passage of time...usually) |
| • | consider adding - singulair 10QD or H2 blockers |
| • | avoid ASA/NSAIDS, opiates, ACE inhibitors, alcohol |
| • | Michael Tharp likes fexofenadine QAM 180mg (or 360mg if needed) and cetirizine QPM |
aggressive antihistamine regimen (from AAD lecture 2011)
| • | fexofenadine 360mg QAM, loratidine 20mg midday, cetirizine 20mg QHS, and ranitidine 150mg PO BID |
| • | add singulair 10mg/day (if still not controlled) |
| • | "can't hurt someone with non-sedating anti-histamines" per speaker |
lab tests (if you have an index of suspicion):
| • | eosinophilia – drug, food, parasite infection |
| • | leukocytosis – chronic infection |
| • | Warren Heyman checks - T4, TSH, anti-thyroglobin, anti-microsomal antibodies |
| • | if recalcitrant urticaria and positive for these auto-antibodies, then he will treat with thyroid hormone... |
| • | levothyroxine 1.7μg/kg/day - check TSH at 4-6weeks to ensure a low-normal level |
last resort:
| • | stool O&P (if eosinophilia) |
| • | refer to dentist (chronic dental infection) |
| • | refer to GI: 13C Urea breath test for H. pylori: treatment amoxicillin 500mg QID plus omeprazole 40QD X 2week, then omeprazole X 2 weeks – |
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