• A man with multiple tattoosTattoo man with headache image by MAXFX from Fotolia.com
  
  Skin tattooing is an ancient art that has been practiced since before recorded human history. The oldest known evidence of tattooing comes from the "Iceman," a mummy who died around 3200 BC. Even as tattooing technology evolves, it remains a controversial subject, including claims of tattoo ink poisoning. Although it's extremely unlikely that you would literally be poisoned by tattoo ink, there are health risks involved with both skin piercing and ink injection.
  
  

Inflammation, Flakiness, or Rash

• A woman with facial henna tattoosnew age image by Silvia Ottaviano from Fotolia.com
  
  One of the more common side effects of tattooing is an allergic reaction to the ink pigment used. Different colors of ink have differing chemical compositions; if you are allergic to one of these, you can develop dermatitis (rash or allergic skin reaction). Even if you're not allergic to the ink itself, you might have a reaction to the carrier: people with henna tattoos (which are not injected) occasionally report dermatitis.
  
  

Redness, Pain and Drainage

• If the site of your tattoo is extremely red, swollen, painful to touch and "weeping" a pus-like substance, you might have a local bacterial infection. This can be a side effect of the needle piercing your skin, especially if your tattooist didn't observe proper sanitary guidelines. If you think you have an infection, see your doctor: it is possible to contract Staphylococcus aureus (staph) via a tattoo needle. However, if your skin is red, painful and oozing directly after your tattoo procedure, don't worry: this is normal.
  
  

Lumps and Bumps

• Your skin might react to the procedure by forming excess scar tissue (keloids) or nodules around the area (granulomas). These are not dangerous to your health, though they might affect appearance of your tattoo. You're more likely to develop keloids if you've had them before, or while removing a tattoo.
  
  

Other Risks

• It is possible to contract bloodborne diseases such as hepatitis, tetanus and even HIV/AIDS from tattooing. Skin infections can result from improper care and cleanliness. These can be avoided by exercising responsibility: Never let a nonprofessional tattoo you, and always make sure she wears gloves, uses sterile equipment and abides by local regulations. After your tattoo, keep your skin clean and covered, using an antibiotic to prevent infection, until the tattoo heals.