Diagnostic Tools for Doctors' Evaluation of Tattoo Complications.

Diagnosis of tattoo complications is a multi-facetted field since many clinical entities and disease mechanisms are represented. Infections, allergies, and pigment foreign body reactions with granuloma are the major groups. The clinician needs a structured approach to diagnosis and an armamentarium of standard tests. Diagnosis primarily builds on patient history, objective clinical examination, and punch biopsy, supplemented with microbiology testing, ultrasound scanning, and clinical photography. Evaluation of allergic tattoo reactions and allergy to pigments by patch testing is not applicable and has a falsely negative outcome except for the diagnosis of allergy to metals and preservatives. Simple inspection of raw punch biopsies from chronic tattoo reactions, preferably evaluated with stereo microscopy, provides important information about the density and the local distribution of tattoo pigment in the dermis and changes of micro- anatomical skin structures. Histology may show subtle structural changes, but traditional patterns (lichenoid reaction, pseudolymphoma, granuloma, and pseudoepitheliomatous epidermal hyperplasia) are of little or no help in the diagnosis since the patterns overlap and have no distinct clinical correlates. Histology cannot separate allergic and nonallergic reactions. However, granulomatous reaction and sarcoid granuloma are significant findings since papulonodular reaction of black tattoos and sarcoidosis are strongly associated with each other. 20-MHz ultrasound scanning is important for noninvasive imaging and characterization of inflammatory tattoo reactions and can be used preoperatively as guide to treatment. Electron microscopy can visualize pigment particles in tissues, cells, and tattoo inks. Chemicals of pigment in tissues and in tattoo inks can be analyzed by high-performance liquid chromatography, mass spectroscopy, and Raman spectroscopy.