The energy of the optical radiation is absorbed – as selectively as possible – by the colour pigments of the tattoo or the permanent make-up. To do this, the wavelength of the laser beam must match the absorbing pigment. With extremely short laser pulses, so much energy reaches the ink particles that they are “shot” into small parts. The resulting fragments should be transported away or degraded by the body.

The colour pigments of the tattoo inks are complex. When some pigments are destroyed, toxic and carcinogenic compounds such as hydrogen cyanide or benzene can be formed. Which fragments arise or are released during their decomposition or destruction and how they behave in the body is largely unknown. There are also no systematic studies on possible long-term effects.

Several sessions necessary

Especially with complex, multi-coloured tattoos, customers must be prepared for a number of treatments. Five to 10 sessions are not uncommon, and sometimes over 20 sessions are necessary. Some tattoos cannot be completely removed at all. Removing a tattoo can be more expensive (and more painful) than getting one in the first place.

This treatment uses optical radiation with irradiance levels or energy densities that pose risks to the eyes and skin. With Class 4 lasers, damage can be caused not only by the direct beam but also by reflected radiation. If the treatment is not performed properly (e.g. if the selection of the laser and/or the selected settings do not correspond to the individual requirements), undesired side effects may occur. These include:

• burns
• temporary or permanent pigment changes (over- or under-pigmentation)
• inflammations
• scarring.

The behaviour of customers and patients can also contribute to undesirable side effects. For example, if precautions or care instructions are not observed or if substances that increase sensitivity to light are taken or applied.

Caution with pigmented skin changes

Especially within dark tattoos, pigmented skin changes are hard to recognise and difficult to classify. There is a risk that a dangerous skin cancer will not be detected or will be detected too late. Especially in the case of malignant melanoma, a diagnosis as early as possible is decisive for the success of the therapy. The factors that apply to epilation therefore also apply to tattoo removal: Pigmented skin changes (e.g. birthmarks or liver spots) should not be superficially changed or removed by laser radiation.

A prior diagnostic clarification by a dermatologist is strongly recommended.

Protection of the eyes is necessary

The iris also contains the pigment melanin and can absorb the radiation. If the radiation hits the eye, permanent damage is possible. In the case of Class 4 lasers, this applies not only to the direct beam but also to the reflected beam. In addition, the wavelengths of visible light and near infrared reach the retina. The eyes must therefore be sufficiently protected during the treatment.

Anyone who applies lasers or strong optical radiation sources on humans needs solid technical knowledge and expertise in order to identify and avoid possible risks. Providers must be familiar with the equipment used and the effects of optical radiation and be able to adapt the treatment to the individual characteristics of the customer or patient.

In order to remove tattoos properly, the provider needs extensive knowledge about the different lasers and the interaction of laser radiation with the respective tattoo inks. They must be able to identify circumstances of the customers or patients that exclude the desired application or allow it only under strict risk-benefit considerations (contraindication).

With the Ordinance on Protection against the Harmful Effects of Non-ionising Radiation in Human Applications (NiSV) only physicians with the appropriate advanced training are allowed to carry out some applications such as tattoo removal as of 31 December 2020.