Yes, It's Possible to Have an Allergy to Vibrations

Imagine if activities like rubbing a towel on your skin after a shower, jogging on a track, or experiencing a rough car ride caused you to break out in itchy hives. This happens to a small number of people. While vibratory urticaria (vibratory hives) is uncommon, it is gaining attention due to a study by the National Institutes of Health (NIH), which has discovered a genetic cause for the allergy. These findings might also offer insights into why people develop allergies to pollen, food, and other substances, an issue that remains largely unexplained.

Researchers studied 36 individuals from three different families. Some of these individuals suffer from vibratory urticaria, while others do not. Though the sample size was small, it became even smaller as the study progressed.

Dr. Dan Kastner, M.D., Ph.D., the scientific director of the Division of Intramural Research at the National Human Genome Research Institute (NIH), co-authored the study. He explains that the first family studied was from a clinic at the National Institute of Allergy and Infectious Diseases, which is part of the NIH and managed by Dr. Hirsh Komarow, M.D. Komarow oversees a group of approximately 60 patients who experience hives from mechanical triggers such as vibrations, cold weather, or exercise, in contrast to those caused by immune responses like pollen or cat dander.

During their investigation into the family's symptoms, the scientists came across a Yale study from the 1980s detailing another family with comparable complaints. The researcher from Yale connected the scientists with this second family, who in turn pointed them to a third family exhibiting the same symptoms. This third family then became part of the study.

Here's where things took a fascinating turn. 'Our [first] family hailed from a city in Lebanon named Zgharta,' Kastner explains. 'Interestingly, the early 1980s publication also mentioned that the [second] family came from Zgharta as well.'

Through DNA fingerprinting, the researchers discovered that the three families were connected. 'They're essentially just different branches of one large family,' Kastner notes.

Those affected by vibratory urticaria experience symptoms like red, itchy hives, headaches, flushed faces, blurred vision, and a metallic taste. While these symptoms aren't life-threatening and usually subside within an hour, they can recur multiple times throughout the day, leading to a rather challenging experience.

In an effort to understand the underlying causes of the hives and other symptoms, the researchers focused on mast cells—cells found in the skin and other tissues that release histamine. While histamine is typically triggered by common allergens like pet dander, the researchers found that mast cells also release histamine in response to vibrations.

The researchers further found that all family members experiencing the symptoms shared a specific genetic mutation on the ADGRE2 gene, which is found in mast cells.

Kastner states, "ADGRE2 seems to function as a mechanosensor. It's responsible for detecting mechanical changes around the mast cell. We know that even in healthy individuals, a certain amount of skin vibration can cause mild hives and histamine release, the chemical mediator involved in allergic reactions. However, these families have a mutation in the gene, making them significantly more sensitive than most people."

This raises a fundamental question – if you're a geneticist – why does anyone need a mechanosensor on their mast cells? Kastner admits, "That’s a question we've been pondering for a while now."

Kastner and his team propose a theory suggesting these sensors may have evolved to respond to threats like parasitic infestations. "The mechanical disturbance caused by a parasite in the skin would prompt mast cells to release chemicals and trigger an allergic response," he explains. "We plan to conduct further experiments to uncover the normal function of ADGRE2."

They are actively seeking new participants to aid with the study. Kastner states, "Since this paper was published online, we've received several inquiries from individuals who say, 'What you're describing in this article is exactly what I have.'"

The identification of the ADGRE2 gene's role in at least three of the study families offers researchers a valuable new tool in their ongoing investigation into the causes of allergies, a field that remains poorly understood.

"I believe this research will lead to a much clearer understanding of what exactly triggers mast cells," says Kastner. "It could potentially open an entirely new field of study."