Current problems in dermatology最新文献

Intracellular pH influences proliferation and differentiation in a range of stem-like and progenitor cells, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, and cancer stem cells. Sodium hydrogen exchanger (NHE1), a glycoprotein that plays a major role in regulating intracellular pH, has a major role in the proliferation and cell differentiation in multiple cell types. We review observations collected on the influence of pH on multiple stem-like cell populations. Altering pH, either intracellular or extracellular, can influence stem cell maintenance, self-renewal, differentiation, and pluripotency. Study of the influence of NHE1 and intracellular pH on epidermal stem cell behavior could lead to the discovery of new targets to use in order to manipulate stem cell divisions. This is highly relevant for skin conditions such as psoriasis, wound healing, and melanoma where stem cell proliferation and migration are key factors.

Early methods of tattoo removal ultimately resulted in unacceptable cosmetic outcomes. While the introduction of laser technology was an improvement over the existing chemical, mechanical, and surgical procedures, the use of nonselective tattoo removal with carbon dioxide and argon lasers led to scarring. Q-switched lasers with nanosecond (10-9) pulse domains were considered to have revolutionized tattoo treatment, by selectively heating the tattoo particles, while reducing the adverse sequelae to adjacent normal skin. Theoretical considerations of restricting pulse duration, to heat tattoo particles to higher temperatures, proposed the use of sub-nanosecond pulses to target particles with thermal relaxation times lower than the nanosecond pulses in Q-switched lasers. Initial studies demonstrated that picosecond (10-12) pulses were more effective than nanosecond pulses in clearing black tattoos. Advances in picosecond technology led to the development of commercially available lasers, incorporating several different wavelengths, to further refine pigment targeting.

Clinicians in the fields of general medicine, dermatology, and plastic surgery are in their work now and then confronted with tattoo complications. Recognizing the rather few important diagnostic groups and urgencies, the medical 'decision tree' of treatment becomes quite simple. Acute conditions are dominated by bacterial infections needing antibiotic treatment. Systemic infection is a matter of urgency and requires intravenous treatment in a hospital without delay to prevent septic shock. Inflammatory reactions are a real challenge. Chronic allergic reactions in red tattoos are mostly nonresponsive to topical corticoid and best treated with dermatome shaving with complete removal of the hapten concentrated in the outer dermis. Laser treatment of allergic reactions can boost the allergy with worsening and a potential risk of anaphylaxis and is thus not recommended in tattoo allergy. Chronic papulonodular reactions in black tattoos with pigment agglomeration can respond to local corticoid or be treated with dermatome shaving or lasers depending on availability. It is important to recognize sarcoidosis, which is strongly associated with reactions in black tattoos. Tattoo complications also include many rare but specific entities, which require individual treatment depending on the case and the disease mechanism. Removal of tattoos in individuals regretting their tattoo is performed using Q-switched nanosecond lasers and the recently introduced picosecond lasers. In view of the various tattoo pigments with different absorption spectra and the limited number of laser wavelengths, it is difficult to predict treatment outcome, and it is recommended to pretreat small test spots. Black and red colors are removed best, while other colors are difficult. Removal of large tattoos, especially when multicolored, is hardly achievable and not recommended. Clients often have unrealistic expectations, and informed consent and dialogue between the client and the laser surgeon before and during a treatment course is important since the client shall know the risk that removal can be unsuccessful, with complications and even disfiguring leading to regret at the end.

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.

Bacterial infection of tattoos remains a common complication. Pyogenic bacteria can cause infections shortly after the tattoo is made. Severity of infection varies from minor to major, ultimately with life-threatening septicemia. Viral infections may be introduced, i.e. HVB, HVC, and HIV. The risk of infection depends on the following triad: microbial pathogen and its aggressiveness, individual resistance of the tattooed, and inoculation and exposures by the tattoo needle and in the tattoo parlor. Some infectious risks can be controlled. Persons with weaknesses can refrain from tattooing. Tattoo parlors and tattooing can be hygienic and clean albeit not sterile; much has improved helped by hygiene guidelines of professional tattooists' organizations and through control instituted by local and national authorities. Tattoo inks remain a potential source of infection difficult to control in a low-priced competitive market operating over the Internet and across national borders. Ten percent of new inks are contaminated with bacteria pathogenic to humans, independent of a claim of 'sterility'. Known brands and established manufacturers are considered safer. Work is in progress aiming at common European standards for tattoo hygiene. Doctors have a role not only in treating tattoo infections but also in reporting cases to the competent authority in their country to support the monitoring of tattoo infections at any time, as an instrument for the authority to detect local outbreaks of tattoo infections early and prevent that new tattoo customers become infected. It is a potential risk of the future that new and very aggressive bacteria not seen in the past may unexpectedly show up in the tattoo scene.

Tattoo removal by Q-switched nanosecond laser devices is generally a safe and effective method, albeit a time-consuming one. Despite the newest developments in laser treatment, it is still not possible to remove every tattoo completely and without complications. Incomplete removal remains one of the most common challenges. As a consequence, particular restraint should be exercised when treating multicoloured tattoos, and patients need to be thoroughly informed about remaining pigment. Other frequent adverse effects include hyper- and hypopigmentation as well as ink darkening; the latter is particularly frequent in permanent make-up. Scarring is also possible, although it is rare when treatment is performed correctly. It is becoming more widespread for laser operators to encounter allergic reactions and even malignant tumours in tattoos, and treating these conditions requires a nuanced approach.

With a continuing increase in the number of tattoos performed worldwide, the need to treat tattoo complications is growing. Earlier treatments of chronic inflammatory tattoo reactions were dominated by a medical approach, or with no active intervention. In this chapter, we will address modern surgical approaches applied to situations when medical treatment is inefficient and lasers are not applicable. Dermatome shaving is positioned as first-line treatment of allergic tattoo reactions and also indicated in a number of other tattoo reactions, supplemented with excision in selected cases. The methods allow fundamental treatment with removal of the culprit pigment from the dermis. The different instruments, surgical methods, and treatment schedules are reviewed, and a guide to surgeons is presented. Postoperative treatments and the long-term outcomes are described in detail. An algorithm on specialist treatment and follow-up of tattoo reactions, which can be practiced in other countries, is presented.

Doctors who are consulted about health and tattoo risks have an important role in the prevention of an individual's tattoo complications. Tattooing is a tremendous exposure of the human body to needle operation, particles, and chemicals. The risk is related to a person's health condition, level of insight, decision-making, and to the operation of tattooing, tattoo inks and utensils, tattoo parlour, and the aftercare. Tattooing is painful minor surgery performed without anesthesia. It can be associated with syncope. It is major needle trauma with histamine release and wheal and flare in the operation field. The skin barrier is broken. Bacterial infections come early. Chronically intermittent and mild complaints affect 4/10 of all the tattooed, and 2/10 have sensitivity to sun. Chronic complications with allergy in red tattoos and nodules due to pigment agglomeration and foreign body formation in black tattoos are less common but certainly at the level of cumbersome skin disease. Reactions to black tattoos are strongly associated with sarcoidosis. There are many other distinct entities of tattoo complications. A campaign called 'Tattoo - know your risk' is presented with detailed fact sheets about tattoos, tattoo problems, how to reduce risk, and a checklist for the tattoo customer before decision-making. The sheets with keynote information are useful aids for doctors giving advice to persons curious about acquiring a tattoo.

Tattoo complications represent a broad spectrum of clinical entities and disease mechanisms. Infections are known, but chronic inflammatory reactions have hitherto been inconsistently reported and given many interpretations and terms. A clinical classification system of distinct patterns with emphasis on inflammatory tattoo reactions is introduced. Allergic reactions prevalent in red tattoos and often associated with azo pigments are manifested as the 'plaque elevation', 'excessive hyperkeratosis', and 'ulceronecrotic' patterns. The allergen is a hapten. Nonallergic reactions prevalent in black tattoos and associated with carbon black are manifested as the 'papulonodular' pattern. Carbon black nanoparticles agglomerate in the dermis over time forming foreign bodies that elicit reactions. Many black tattoos even develop sarcoid granuloma, and the 'papulonodular' pattern is strongly associated with sarcoidosis affecting other organs. Tattoo complications include a large group of less frequent but nevertheless specific entities, i.e. irritant and toxic local events, photosensitivity, urticaria, eczematous rash due to soluble allergen, neurosensitivity and pain syndrome, lymphopathies, pigment diffusion or fan, scars, and other sequels of tattooing or tattoo removal. Keratoacanthoma occurs in tattoos. Carcinoma and melanoma are rare and occur by coincidence only. Different tattoo complications require different therapeutic approaches, and precise diagnosis is thus important as a key to therapy. The proposed new classification with characteristic patterns relies on simple tools, namely patient history, objective findings, and supplementary punch biopsy. By virtue of simplicity and broad access, these methods make the proposed classification widely applicable in clinics and hospitals. The system is reported to the 11th revision of the WHO diagnosis classification used as international standard.

Tattoo colourants are colourful nano- and microparticles, which are practically insoluble and thus permanent once installed in the dermis by the tattooist. Tattoo ink also has soluble ingredients and contaminants. Pigments can distribute via the lymph and possibly also directly to the blood, and a minute fraction may over time undergo metabolic breakdown and as hapten(s) induce allergic reactions of red tattoos. Carbon black of black tattoos has a tendency to agglomerate and form larger bodies that can elicit foreign body reactions in black tattoos and even granuloma formation with overlap to sarcoidosis in the clinic. Very little is known about the biokinetics and safety profile of the many tattoo pigments in use, and no specific pigment-related chemical of tattoo ink causing identified adverse reactions in humans has been depicted. Inks have many ingredients and contaminants. Insoluble and soluble ingredients of inks supposedly have very different characteristics of absorption, distribution, metabolism, and excretion, with pigments being extremely slowly excreted, contrasting soluble ingredients with fast elimination. Tattoos are a single-dose exposure. Controlling the safety of tattoo inks by banning potentially critical chemicals hitherto has been unsuccessful due to lacking documentation of clinical and epidemiological relevance and because the tattoo industry is already internationally established, free, and in the ownership of the people. Doctors treating patients with tattoo complications consequently have a key role in identifying risk situations and local outbreaks, which needs clarification, therapy, and the intervention of authorities. In the treatment of complications, as seen in general practice and in other specialties, basic insight into the fate of tattoo pigments in the body is necessary. Tattoo complications are complicated and facetted with many entities and disease mechanisms; they are a new subspecialty in medicine and dermatology.