Pigments in US Cosmetic Tattoo Ink Can Trigger Allergic Contact Dermatitis

In the United States, some organic and inorganic pigment ingredients used in cosmetic tattoos, also known as permanent makeup, are known causes of allergic contact dermatitis (ACD), according to study findings published in the Journal of the American Academy of Dermatology.

Prevalence of tattoos in the US may be as high as 31.5%. The industry is valued at $1.89 billion with an estimated compound annual growth rate of close to 10% through 2030; uptake of permanent makeup is expected to grow at an even higher rate. Similar to decorative tattooing, permanent makeup or tattooing involves repetitive intradermal penetration with an ink-loaded needle. Cosmetic/permanent makeup tattoos are typically applied to lips, eyelids, eyebrows, and areolas, or to camouflage scars. In general, permanent makeup tattoos are applied more superficially than traditional tattoos and are designed to fade over time.

Ink for decorative tattoos historically contained mercury or cadmium and heavy metals, although there has been a shift toward increased use of organic pigments instead. While traditional decorative tattoos are known to sometimes trigger ACD, it is unclear whether permanent makeup carries the same risk. Therefore, US investigators from Chicago sought to identify listed pigments used in permanent makeup inks sold in the US and characterize their association with ACD.

They conducted a comprehensive internet and online medical literature search in July 2023 to identify permanent makeup inks sold in the US and to find cases of ACD linked to certain PMU pigments. The first 20 websites that sold or manufactured permanent makeup products or pigments in the US were included in the current study. Safety data sheets were used to catalog each of the identified pigments used in permanent makeup by the specific name and color index; products without safety data sheets or with incomplete sheets were excluded from the study.

A total of 25 permanent makeup brands provided complete safety data sheets for their inks and 32 brands did not. Overall, 79 distinct pigments from 974 products were identified across the 25 brands with complete safety data sheets. The mean number of pigments per product was 4. There were 3 times as many organic pigments (59) vs inorganic pigments (20). Distinct pigments were used in permanent makeup inks that are not found in inks used for traditional decorative tattoos. Organic pigments included quinacridone, azo, sulphonic acid, methine, anthraquinone, and others. Inorganic pigments included the metals iron, manganese, molybdenum, silicone, copper, titanium, aluminum, and chromium; the latter 2 metals are known to cause ACD.

Although 10 of the 79 identified pigments were associated with ACD in 29 patients, patch testing was confirmatory in just 18 cases. Traditional patch testing to these ingredients can be negative even if a pigment allergy is suspected, according to the investigators.

In discussing treatment options for permanent makeup reactions, the investigators noted that contact dermatitis from tattoo ink is “notoriously hard to treat,” and that ACD reactions to permanent makeup are treated in the same way that ACD from traditional tattoos is treated. They explained, “Reactions are initially treated with intralesional or topical corticosteroids, often under occlusion. Systemic therapy with immunomodulating drugs [has] been proposed for severe or generalized reactions.” They added that tattoo removal may be necessary to treat persistent reactions, the benefits and risks of which should be discussed with the patient.

Additional challenges to confirmation of ACD caused by permanent makeup include biologic ones: Over months to years, pigments undergo haptenization, degrading into different molecules as a result of skin exposure to sunlight or laser irradiation, or due to metabolism; many cases of ACD may not be due to the initial pigment but instead may result from skin reaction to a pigment breakdown product. Also, given that tattoo pigments reside within the papillary dermis rather than the epidermis, intradermal testing of a pigment [which would result in permanent tattooing of the skin] may elicit an allergic response in a patient who is nonresponsive to patch testing, making the clinical value of patch testing in this setting uncertain.

Following permanent makeup procedures, patients may also react to inactive ingredients in the ink, such as formaldehyde; materials used in wound care; or fragrance in aftercare soaps and lotions.

Study limitations include the investigators’ inability to evaluate the 32 brands of permanent makeup inks that did not provide complete safety data sheets. Additionally, safety data sheets were limited by what information the manufacturers chose to disclose, which may not be accurate. The investigators also cautioned that, while they were able to identify ACD likely to have been caused by permanent makeup pigments, the pigments without a reported history of ACD are not necessarily nonallergenic.

The researchers concluded, “Our findings demonstrate that most pigments used in [permanent makeup] inks sold in the United States are organic dyes, and some of these have been reported to cause ACD.” They added, “However, identifying pigment allergies is stymied by limitations in the regulation and labelling of [permanent makeup] inks. Furthermore, traditional patch testing methods may not be useful in confirming the presence of a pigment allergy, even if one is suspect. Ultimately, consumers and patch testing physicians would benefit from better labelling of tattoo inks and the development of protocols designed to specifically test for tattoo pigment allergies.”