Vibration Allergies Are Real and Appear to be Caused by a Genetic Mutation

A rare skin allergy triggered by vibrations is caused by a genetic mutation, according to a new study published Wednesday in The New England Journal of Medicine. Researchers at the National Institutes of Health (NIH) have uncovered critical information about vibratory urticaria, a condition that produces giant, itchy and unsightly welts triggered by everything from bumpy car rides to hand clapping and the thumping of bass.

Vibratory urticaria also causes flushing, blurry vision and a metallic taste in the mouth. Thankfully, all of these unpleasant symptoms disappear within about an hour, but that doesn't mean they're any less debilitating—or embarrassing. Doctors typically diagnose the condition by having a patient hold a vibrating device for a few minutes on his or her forearm. If the hives appear, a diagnosis may very well be vibratory urticaria.

In people with vibratory urticaria, vibrating sensations cause the immune system's mast cells to produce certain inflammatory chemicals, which leads to hives. Mast cells are a type of cell in skin and other connective tissue that releases histamines and other inflammatory chemicals in reaction to certain stimuli. The process is in place to safeguard against infections and harmful things in the environment. But sometimes the function of these cells goes awry, thanks to the hand genetics has dealt someone.

To probe the mystery of this strange condition, researchers at the National Institute of Allergy and Infectious Diseases and the National Human Genome Research Institute, both part of the NIH, looked at the underlying genetic traits in three families affected by vibratory urticaria for generations. Researchers measured the histamine levels in blood when a patient broke out in the hives and found that histamine levels rose when the person was confronted with some sort of vibration stimulus. The skin inflammation then dissipated in about an hour. Additionally, the researchers observed elevated levels of tryptase, an enzyme produced by mast cells as part of an immune response.

Next the team conducted a DNA analysis for a total of 36 people with the condition and some without it, all of whom came from the same three families. The researchers identified a single mutation in the ADGRE2 gene in the people with vibratory urticaria that wasn't present in relatives without the condition.

ADGRE2 is responsible for producing a protein made up of two subunits: the "beta," located within the cell's outer membrane, and the "alpha," on the cell's outside surface. It turns out that people with vibratory urticaria produce a mutated version of this specific protein that causes it to function differently within mast cells. In the mutated version, these two subunits don't stay close together, and this causes an aggressive immune response, which develops into the many potential symptoms of vibratory urticaria.

Studying a novel and rare disorder can help scientists understand much more common conditions. For example, after this study on vibration allergies, we now know that interactions between the two subunits of ADGRE2 most likely play a role in mast cell responses to other physical stimuli as well.

Urticaria (from the Latin urtica, "stinging nettle," in turn derived from urere, "to burn") occurs for a number of unusual reasons. People with aquagenic urticaria are essentially allergic to water, which means suffering through a breakout of hives all for the sake of a shower. Others may develop urticaria from sun exposure, also known as "photosensitivity." Hives can also result from cold exposure or extreme heat and even exercise. Dermographism—which means "skin writing"—is an allergy to touch.

Though researchers don't yet know for sure, it's possible that mast cells may be involved in other skin allergies in the same way they are with vibratory urticaria.