Gustatory Sweating/Frey's Syndrome
It's not uncommon to sweat when eating hot or spicy foods.
But some patients sweat when they eat almost any type of food, and some patients can sweat simply when they think about food. Called gustatory hyperhidrosis or Frey's syndrome, this can be embarrassing and uncomfortable for patients.
Many cases of gustatory sweating arise after surgery or trauma to a parotid gland, the body's largest salivary glands. If a parotid gland is damaged or if surgery to a parotid gland is required, then related nerves may become damaged or may regenerate from such damage in a way that causes them to become intertwined. The result is that when a patient is supposed to salivate, he or she may also sweat and experience facial flushing. The combination of sweating and flushing related to parotid trauma is called Frey's syndrome. Usually Frey's syndrome affects just one side of the face.
Gustatory sweating can also be idiopathic or secondary. In these cases, the sweating is often experienced on both sides of the face and particularly on the temples, forehead, cheeks, neck, and/or chest, as well as around the lips. Redness and sweating may appear when an affected patient eats, sees, thinks about, or talks about foods.
Gustatory sweating can be distressing because the idea of food can make a patient's face drenched with sweat. And because much of life is conducted at mealtime, gustatory sweating can have social, economic, and emotional implications.
According to Dr. David Pariser (founding Member and Secretary of the International Hyperhidrosis Society and 2009 President of the American Academy of Dermatology), Botox injections can provide "a couple of years" of relief from gustatory sweating. This is a much longer duration of effectiveness than is typically seen when Botox is used to treat other forms of hyperhidrosis. (This is an off-label use.)