To find the prevalence of complaints in people having tattoos, with emphasis on chronic complaints, photosensitivity and photodynamic events.
Individuals sunbathing from June to September 2011 at the beaches of Denmark were invited to participate as they are prone to report tattoos and sun habits reliably. Sun-related and non-sun-related problems in tattoos were determined along with participants' use of sunscreen. Skin type was categorized, as were motifs and colours associated with problems.
Of 467 sunbathers, 146 (31.3%) had tattoos. A total of 144 sunbathers with 301 tattoos accepted inclusion. Complaints were experienced in 60/144 (42%), of which 31/60 (52%) were sun related, such as swelling (58%), itching/stinging/pain (52%) and redness (26%). Reactions independent of sun were 29/60 (48%), such as reactions to heat 12/29 (41%) and cold 1/29 (4%). Red, blue and black tattoos predominantly caused sun-related complaints followed by the remaining colours. By number, problems in black tattoos dominated as black was far more frequent.
Complaints such as swelling, itching, stinging, pain and redness are common, predominantly in black and red tattoos, but also frequent in blue tattoos, thus, not confined to one specific colour or chemical entity or class of pigment. Symptoms may switch on and off in seconds, typically not of the weal-and-flare type. Photochemical reactions to pigment or pigment-breakdown products in situ in the skin with induction of reactive oxygen species (ROS) is presumed to be one causative mechanism. Another possible mechanism especially relevant in black may be induction of ROS due to effects of aggregation of carbon black nanoparticles.