Urticaria (Hives)/Angioedema (Tissue Swelling)
Most “hives” are caused by histamine and other mediators “released” in the upper layers of the skin.
Histamine can be released from special cells, mast cells and basophils, which are found in everyone’s skin.
Patients with hives release “too much” histamine when it is not needed and are classified as:
- “Acute hivers” only when they take in an identifiable “trigger”, i.e., drug, food, etc. or if hives last less than 6 weeks.
- “Chronic hivers” daily or almost daily without an identifiable “trigger” and lasting for greater than six weeks.
In “chronic” urticaria or persistent hives, a “trigger” is rarely found. A “complete” history is needed to look for identifiable “triggers”.
The etiology for chronic urticaria such as medication, heat, pressure or infection is found in less than 5% of patients.
For most cases of chronic urticaria the etiology will remain idiopathic (cause unknown) although an autoimmune etiology can sometimes be found.
- Angioedema (tissue swelling), occurs in 90% of patients with chronic urticaria
For chronic urticaria laboratory evaluation can be performed: Thyroid auto-antibody profile, CU Index, complete metabolic profile, complete blood count and autoimmunity tests.
Fortunately, most chronic hives go away with or without treatment:
- 50% of patients hives go away in 3-12 months
- 20% of patients hives go away in 12-36 months
- 20% of patients hives go away in 36-60 months
- 1.5% of patients can have hives for up to 25 years
60% of “chronic” hivers have recurrences of the hives
Management is directed toward keeping patients “comfortable” with or without some hives being present. This can be achieved with “appropriate” antihistamine therapy, and occasionally with “other” medications. Prednisone (steroid) should be avoided if at all possible.
Remember the potency of:
- Benadryl 50mg. is considered — a strength of 1
- Clarinex, Claritin, Allegra — a strength of 2-3
- Atarax (hydroxyzine 25mg.), Zyrtec, Xyzal — a strength of 88
- Doxepin (Sinequan) 25mg — a strength of 779