#21 Steroids for acute urticaria

By Dr. Daniel Aronov

A patient presents with acute urticaria (hives) and after your comprehensive assessment, you decide to give them an antihistamine. But do you also give them a corticosteroid? Maybe some prednisolone to speed up the recovery from their hives? It’s a pretty common practice, in a study of one emergency department in Italy, 93% of those presenting with acute urticaria where treated with steroids on top of their antihistamine. But does it actually add any benefit on top of antihistamines? This episode we explore the evidence

Approximately 10% of the population will develop acute urticaria at some point and most of the time we have no idea what causes it. Idiopathic urticaria, where no trigger is identified, is actually the most common cause (60% of cases). When a trigger for the urticaria is identified, in about 40% of cases, most are due to drugs, then insect bites, then foods.

There have only been 2 randomised controlled trials to answer today’s question. One done in the United States in 1995 and the other done in France in 2017.

Pollack, 1995

This was conducted out of one Emergency Department in Phoenix, Arizona in America. Anyone who came into this Emergency Department over a 7 month period with a generalised itchy, urticarial rash was enrolled in the study. The rash had to be present for less than 24 hours and if they had any signs of a more serious allergic reaction, like angioedema or stridor, then they were excluded. They were also excluded if it was only a local allergic reaction or if they had already used an antihistamine or steroid in the previous 5 days.

They were all given a 50mg intramuscular shot of diphenhydramine in the emergency room and then randomised into two groups: This first group were sent home with an antihistamine (hydroxyzine)  and prednisolone (20mg twice per day for 4 days).  The second group were sent home with an antihistamine, plus a placebo to take twice per day for 4 days.

They recruited 43 patients all together, 19 in the placebo group and 24 in the prednisolone group. The primary outcome was the average change in Itch Score (0-10 itchiness rating) at day 2 and day 5

Results

The average itch score when they presented to the ED was somewhere between 7.5 and 8. On day 2, the average itch score was 4.4 in the placebo group and 1.3 in the steroid group (a  3 point reduction in the 10 point itch scale with adding prednisolone to the antihistamine). At the 5 day mark, the itch score was 1.6 in the placebo group and 0 in the steroid group.

Barniol, 2017

This study recruited 100 participants presenting with acute urticaria to one of 2 emergency departments. Again they were excluded if they had angioedema or anaphylaxis. They had to have had the rash for less than 24 hours and they can’t have used steroids or antihistamines within the last 5 days.

They were randomised to either antihistamine plus steroid or antihistamine alone. The antihistamine they used this time was levoceterizine 5mg daily for 5 days and for the steroid, they used prednisolone 40mg once daily for 4 days.

 

The primary outcome was how many people had an Itch Score of 0 out of 10 on day 2.. They also checked itch scores at 5 days, 15 days and 21 days.

Results

At  2 days: 79% of those in the placebo group had absolutely no itch (An Itch Score of 0 out of 10 ), But in the prednisolone group, 62% had an itch score of 0. This was the only statistically significant result. All other results: Itch Score at 5, 15 and 21 days and complete resolution of rash were not statistically different between the two groups.

Bottom Line

There have been 2 randomised controlled studies assessing the benefit of steroids on top of antihistamines for the treatment of acute urticaria. One study from 1995 with 43 patients found that steroids improved itch scores by 3 points on a 10 point itch scale by day 2.  The second study had 100 patients and was done in 2017. It showed that steroids DID NOT improve recovery from acute urticaria when added to antihistamines.

So what should we do?

  • Option 1:  The better study showed that steroids did not improve outcomes so stop using them for acute urticaria.
  • Option 2: Even if the first study is true and steroids speed up recovery from acute urticaria by a little bit,  they all eventually got better anyway so it’s not worth the potential for side effects with systemic steroids.
  • Option 3: There is some evidence steroids improve recovery so we should use them.