Dear Dr. Roach: I’ve read in several sources that tattoo ink contains known carcinogens and that getting tattooed can cause skin reactions years after. I also read that tattooing can lead to keloids. Recently, I came across a study noting that tattoos were associated with a 21% increased risk of malignant lymphoma. It said that the risk goes above and beyond the concern of non-sterile tattoo practices, which lead to the transmission of blood diseases like hepatitis B.
Are these risks overblown, or do these reports reflect legitimate concerns? Getting inked is becoming increasingly mainstream.
E.D.
Professionally done tattoos have little risk when the aftercare instructions are followed, but there are still some health risks. The most common reactions are due to the ink. Delayed-type hypersensitivity reactions occur infrequently, but when they do, it’s normally days after the tattoo. Long-term reactions rarely happen after months or even years, but they are most often associated with the dyes used to make red colouring.
Keloids (a thick scar caused by an overactive healing process) are a separate issue and can absolutely be a problem with tattoos, as well as many other procedures. People with a history of keloids should be very cautious about getting a tattoo.
Professional tattoo parlors use good techniques and disposable needles, so the risk of hepatitis and other infectious complications has decreased to almost zero. Of course, amateur tattoos have an increased risk. Tattoo inks and dyes are not well-regulated by the Food and Drug Administration, and some have been identified as carcinogenic (cancer-causing). However, most studies have not shown an increase in cancer risk.
The recent study suggesting a 21% increase in the risk of lymphoma needs to be interpreted with caution. Firstly, the study did not quite meet the criteria for statistical significance, meaning this might be a chance correlation. Secondly, the people in the study who got lymphoma might be at a higher risk for reasons other than their tattoos. People who get tattoos are somewhat more likely to drink and smoke, which are risk factors for lymphoma as well.
Finally, 21% sounds like a big increase, but the risk of developing lymphoma between the ages of 20-60 is low. So, a 21% increase means that the actual risk attributable to tattoos (if any) is small.
Dear Dr. Roach: I am a 72-year-old man, and I take medicine for high blood pressure and diabetes, which are both under control. I drink 10 bottles (16.9 ounces) of water per day. Does the amount of medicine you take affect how much water you need? Don’t medications dehydrate you?
M.I.T.
There are a few medicines that make drinking water more important, but there are also a few medicines where excess water drinking can be quite dangerous, especially in older people. One common class of blood pressure medicines — diuretics — can lower the blood sodium level, which can be greatly exacerbated by drinking the 5 liters of water a day that you are drinking.
The best rule of thumb for nearly everyone is to drink when you are thirsty. People who are exercising outdoors, especially in hot or dry conditions, certainly need extra water, but I see far more problems from excess water drinking. Water intake should be closely related to a person’s activity and environment more than their medications.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected]
