Chronic idiopathic urticaria (CIU) typically lasts one to five years. Nevertheless, in 14% of CIU patients, the disease lasts longer than five years, and few predictors of its remission rate are available. However, a pair of Thai investigators recently showed that the results of two simple skin tests could predict two-year remission rates in patients with CIU.
In the study, Tadech Boonpiyathad and Atik Sangasapaviliya at Phramongkutklao Hospital in Bangkok, Thailand, evaluated whether two autologous skin tests could predict disease severity and long-term outcomes in 128 patients with CIU. The tests require intradermal injection of serum or plasma taken from the patient’s own blood.
The researchers divided the patients into four groups based on the results of the two tests. After comparing these groups, they found that the odds of remission within two years were five times greater in the group with negative results for both tests than in the group with positive results for both tests (confidence interval 1.61–15.44, P
After two years of follow-up, the researchers found a remission rate of 81% in the group with negative results for both tests, 62% in those with only a positive serum test result, 60% in those with only a positive plasma test result, and 46% in those with positive results for both tests.
According to the researchers, many (63%) of the patients they studied were sensitive to house dust mites, as indicated by results of skin prick testing, but allergy to these mites did not significantly influence disease remission.
Regarding disease severity, the researchers found no significant differences between groups in urticaria severity score (USS) or dermatology life quality index (DLQI). However, for both tests, they noted a positive correlation between the mean diameter of the wheal produced and DLQI. They also noted a positive correlation between mean wheal diameter after plasma testing and USS.
Regarding therapy implications, the researchers found that the proportion of patients whose CIU was resistant to a four-fold dose of H1-antihistamine was significantly greater in the group with positive results to both tests than in the group with a positive result to the serum test alone (P
= 0.03) or the group with negative results to both tests (P
The researchers noted that, although negative results for both tests indicate a good prognosis and disease remission within two years, positive results for both tests indicate that treatment may be challenging and the duration of CIU may be prolonged. After finding this association between test results and disease course, they concluded that clinicians should assess CIU patients with autologous serum and plasma skin tests before starting treatment.
Their study, “Autologous serum and plasma skin test to predict 2-year outcome in chronic spontaneous urticaria
” was published in the October, 2016, issue of Asia Pacific Allergy
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