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AND THE ANSWERS ARE . . .

  1. There is an increased incidence of thyroid autoimmunity in those with CIU
    True
  2. Food allergies play a pathogenic role in the majority of CIU cases
    False
  3. Almost all cases of CIU remit within 5 years
    False
  4. Antibodies against the high affinity IgE receptor (Fc epsilon RI) are present in the sera of 30-40% of individuals with CIU
    True
  5. Individual hives lasting more than 24 hours increases the likelihood that the CIU is due to cutaneous vasculitis
    True

Discussion
CIU is likely a heterogeneous group of disorders in several respects. Although the CIU remits within 2 years in a sizable percentage of individuals, CIU persists for at least 5-10 years in about 25% of cases. Unlike the situation in acute urticaria, food allergy has been detected as a pathogenic mechanism in only a small percentage of CIU cases.

Recent studies indicate that autoimmunity may be pathogenic in about 30-40% of CIU cases. Most commonly, this is manifest as antibody activity against the Fc epsilon RI present on basophils and mast cells. Anti-IgE antibodies are less common in CIU (about 5-10% of cases). Anti-thyroid antibodies, most commonly anti-thyroid peroxidase (anti-microsomal) are present in the serum about 20% of CIU patients, as compared to a 3% incidence in age matched normal controls. Evidence of other auto-immune reactivity in CIU has been inconsistent, and therefore debated. However, the pathogenic effects of serum factors in CIU has been inconsistent, and therefore debated. However, the pathogenic effects of serum factors in CIU is suggested by the findings in one study that marked transient, improvement in the CIU skin manifestations occurred in at least some patients following plasmapharesis treatment.

Biopsies of skin lesion in CIU typically shows a limited number of inflammatory cells and no vascular damage. However, when individual lesions last over 24 hours, particularly when there is residual pigmentation in the site, it is more likely that cutaneous vasculitis is present.



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