Vaccines, Allergy, and Hives – oh my!
Allergic to vaccines? Maybe. Maybe not. In a recent article that we published in the Journal of Dermatology and Dermatologic Surgery, we reviewed several cases of urticaria (hives) seen in our patients following vaccination for COVID-19. The hives appeared generally between 1-2 weeks after the shot, and quite often, persisted for months. Many of our patients did not even make the association between the hives and the shot until we brought it to his or her attention.
So, what are hives anyway? Hives, or urticaria, is an itchy rash that can appear on the skin in minutes. Each individual itchy bump or patch typically will last a few minutes to a few hours. While each spot can appear and disappear within 24 hours, the overall rash can last for weeks — even years in some rare cases. The spots on the skin—called wheals—appear as a result of histamine inappropriately released within the dermis. This is why medications called “antihistamines” work for controlling symptoms of hives. While they are not a true cure, they can help prevent the appearance of rash and help prevent patients from itching.
It is important for patients to recognize that, quite often, hives are not due to allergy, and allergy testing may not be helpful. It is most often a non-allergic immune system reaction. The hives are triggered by antibodies that someone made following upper respiratory infection (the common cold) or sometimes as in the paper mentioned above — to vaccination. Most antibodies decrease over time, and so too will the hives.
Are there other causes of hives?
- Other types of infections can cause hives, such as viral hepatitis, parasites, or infection with H.Pylori
- Stress — simply being stressed out from your medical training (I would know!) or stress of having a sick loved one. These can cause a type of hives.
- Physical stimuli, such as pressure, cold, water, can also cause another type of hives. When hives appear shortly following pressure or a scratch, we call that dermatographia.
- And of course — allergy! When hives are due to a true allergy, the culprit is usually a food, a medication, or some sort of protein – like pet dander. Plants can cause hives, but more often cause a different rash (eczema – more on that later).
While most forms of hives are not life-threatening, the rash can sure be itchy and miserable to experience. Most hives resolve within 6 weeks. Hives lasting longer than 6 weeks, we call them “chronic.” This cutoff of 6 weeks really has no significance in terms of underlying cause or your ability to get better. Taking non-sedating antihistamines (such as Claritin) is a good place to start. If you are having trouble getting your hives under control, it would be good to speak with a dermatologist that is familiar with such skin diseases and their treatments. You may not even have hives, but some other rash. It’s best to first start with an evaluation of what you actually have and what you have already tried. There are several good prescription medicines to treat chronic hives. Either way, we can help!
Antia C, Baquerizo K, Korman A, Bernstein JA, Alikhan A. Urticaria: A comprehensive review: Epidemiology, diagnosis, and work-up. J Am Acad Dermatol. 2018 Oct;79(4):599-614. doi: 10.1016/j.jaad.2018.01.020. PMID: 30241623.