Introduction

Tattoos have long been a form of self-expression, cultural identity, and artistry. Permanent tattoos have been increasingly popular, with an estimated prevalence of 10-20% in adults. While tattooing is generally safe when performed under strict hygiene standards and by licensed professionals, the procedure itself involves penetration of the skin barrier. This process can facilitate the entry of microbes through the epidermal layer, causing local skin infections. Access to blood vessels in the dermal layer promotes more severe, systemic symptoms such as sepsis, endocarditis, and cardiac insufficiency. Among the most concerning complications are bacterial infections, which can range from mild to severe systemic illnesses.¹

Tattoo-related bacterial infections can arise through inappropriate infection control, ink contamination, inadequate wound care, and pre-existing skin conditions. The most common infections are caused by Staphylococcus species, Streptococcus species, and Nontuberculous mycobacteria (NTM). These bacteria can cause complications such as abscesses, impetigo, cellulitis, necrotising fasciitis, septic shock, and multi-organ failure in severe cases. While many infections can be treated with antibiotics, the emergence of antibiotic resistance coupled with serious complications is a challenge.^1,2

Understanding the cause, symptoms, and prevention strategies for bacterial infections in tattoos is essential to ensure safety for both tattoo artists and recipients. 

How do bacterial infections occur in tattoos?

Published surveys estimate that 0.5%-6% of individuals with tattoos experience infectious complications, the severity of which depends on the pathogen itself, the immune system of the recipient, and underlying diseases. It has been previously thought that the main reasons for tattoo-related bacterial infections were associated with poor hygiene practices at the time of the tattoo application and insufficient aftercare, though recent studies have shown that tattoo inks themselves can be contaminated.^1,2

Insufficient hygiene 

Pathogens could originate from surfaces in tattoo studios, inadequately sterilised equipment, or the commensal microbial skin flora of the tattoo artist or recipient. Tattoo wounds can also be infected during healing due to inadequate personal hygiene. Studies have shown that poor sterilisation practices and more invasive tattoo procedures are risk factors, with higher cases of Methicillin-resistant Staphylococcus aureus (MRSA) seen in people who received tattoos from unlicensed tattooists, suggesting suboptimal infection control procedures.^1,3

Ink contamination

Recent studies have shown that ink contamination is a cause of major bacterial outbreaks associated with tattoos. Unopened or sealed bottles of tattoo inks were shown to be contaminated with microorganisms, including pathogenic bacteria, suggesting the applied colourant may have been contaminated during application or prediluted during production.²

Opened ink bottles may have been contaminated during usage over several months. A study detected high levels of gram-negative aerobic bacteria, including Pseudomonas aeruginosa in open bottles. P. aeruginosa can colonise various environments, including tap water, marine water and human skin. This suggests that it can act as an opportunistic pathogen, potentially invading the skin following a compromised skin barrier.¹

Several studies of NTM infections identified dilution of tattoo ink with non-sterile water as the most frequent cause of transmission. People using grey tattoo ink were 8.2 times more likely to report signs of infection. It has been suggested that using distilled or tap water for dilution is a likely source of outbreak, with high levels of different NTM species detected in clinical specimens, tap water, and opened ink bottles.^2,4

Common bacterial pathogens associated with tattoos

Staphylococcus spp.

Staphylococcus spp. are gram-positive bacteria found as part of the commensal flora of the skin and have been detected in both opened and unopened ink bottles, suggesting opportunistic invasion following the broken skin barrier. A study identified Staphylococcus spp. as the most prevalent taxa, with eight different species able to contribute to skin infection.³

Both S. aureus and MRSA were among the species detected, with transmission most likely through ink contamination and unhygienic tattooing conditions. Rare tattoo-related complications following infection were toxic shock syndrome and staphylococcal scalded skin syndrome. Another study also suspected tattoo-related infective endocarditis in individuals with prior heart disease infected with S. aureus or S. lugdunensis, with visible symptoms manifesting within a week of tattoo placement.^1,5 

Streptococcus spp.

Streptococcus spp. are gram-positive bacteria that have been found in contaminated ink and tap water. The most common species is Streptococcus pyogenes, which causes acute pyogenic skin infections following tattoo administration. In most cases, symptoms are mild and can be easily treated with antibiotics, though some severe complications can arise if left untreated.¹ 

Multiple studies have identified group A Streptococcus through wound cultures. Although normally associated with skin and throat infections, some individuals can present with fever, pain, cellulitis, and necrotising fasciitis, which requires acute surgery. Further investigation attributed these symptoms to inadequate sterilisation, non-sterile ink storage, and the reuse of gloves.^6,7

Nontuberculous mycobacteria (NTM)

NTM species such as M. chelonae, M. haemophilum, and M. abscessus are common infectious agents detected between weeks to months after tattooing. M. chelonae is the most common and requires prompt treatment with antibiotics. NTM are normally found in biofilms in drinking water systems, with high levels of M. abscessus detected in tap water. Different NTM species were detected in greywash ink and skin biopsies of people with symptoms of tattoo infection, suggesting that contamination of ink with tap water is a likely source of infection. M. chelonae was also detected in unopened bottles of greywash ink, indicating that pre-dilution during manufacturing is a potential cause.^1,2,4

Cutaneous exposure to NTM from skin infections and penetration of the skin can lead to localised skin illnesses such as rashes, papules, pustules, and nodules. Eradication of infection is generally associated with good outcomes following antibiotic treatment over several months.¹

Signs and symptoms

Infectious bacterial complications of tattoos range from mild skin reactions to severe, rare systemic complications. Acute pyogenic skin infections occur within days, and symptoms are seen in MRSA, S. aureus, Streptococcus spp., and P. aeruginosa infections.¹

Complications from superficial infections include fever, pain, itching, impetigo (sores and blisters), cellulitis (redness and swelling), and erysipelas (red rashes), as well as multiple abscesses (pus-filled swelling) or pustules. These symptoms are easily treated by antibiotic administration. A study identified red papules or papular rashes at the tattoo site restricted to the grey-color region, further evidence that unsterile tap water used in ink dilutions is a reservoir for bacteria.^1,2,4

Complications from systemic infections, as a result of bacteria entering the bloodstream, can lead to life-threatening effects. Although rare, these include endocarditis (inflammation of the heart) and septic shock, which can lead to multi-organ failure. A study identified cases of acute heart failure as a result of septic shock, where the used ink was contaminated with high levels of gram-positive bacteria. Intravenous antibiotic treatment was required in the hospital setting. Necrotising fasciitis is also a rare complication characterised by infection of deep tissues beneath the skin, leading to muscle and fat tissue destruction, which requires immediate hospitalisation and intravenous antibiotic administration.^1,3,5-8

Diagnosis and treatment

Most individuals experiencing symptoms of infection following tattoo administration seek medical attention. An infection can be confirmed by doctors through the symptoms experienced and lab tests confirming the specific bacteria causing the infection.²

Antibiotics are commonly prescribed to treat bacterial infections, depending on the severity and type of bacteria. Most individuals respond well to medications taken for up to 6 weeks. More severe infections may require hospitalization and intravenous antibiotics. An NTM infection is most commonly detected, with M. chelonae diagnosis requiring clarithromycin alone or in combination with quinolones for 6-9 months. It should be noted that some infections are resistant to antibiotics, such as M. abscessus, which may require surgical interventions as treatment to remove affected skin.^1,2,4

Prevention strategies

To lower the risk of tattoo-related bacterial infection, consider the following:¹

• Choose a licensed tattoo artist and inquire about the ink used and sterilisation practices 
• Maintain appropriate hygiene after getting tattooed, ensuring to clean consistently and avoid any contamination
• Seek medical attention immediately if any skin-related symptoms arise, including redness, rashes, swelling, or pain

Summary 

Tattoos are forms of self-expression and cultural identity, and are becoming increasingly more popular. Although tattoo-related bacterial infections are rare, they can arise through inappropriate infection control, ink contamination, and poor aftercare. Common bacterial infections include Staphylococcus species, Streptococcus species, and nontuberculous mycobacteria (NTM), which cause mild symptoms such as fever, pain, impetigo, or cellulitis. In rare cases, septic shock and multiorgan failure are severe and potentially fatal complications that require immediate medical attention. Identifying signs of infection and seeking prompt medical attention is crucial to prevent severe symptoms, with antibiotics being successful in combating infections. Prevention strategies of tattoo-related infections include seeking licensed professional tattooists and maintaining appropriate hygiene.