Fluorescence photography in the evaluation of hyperpigmentation in photodamaged skin

Autofluorescence Excitation Imaging of Nonmelanoma Skin Cancer for Margin Assessment Before Mohs Micrographic Surgery: A Pilot Study

BACKGROUND

Autofluorescence photography can detect specific light-tissue interactions and record important pathophysiological changes associated with nonmelanoma skin cancer (NMSC), which has been ascribed to the fluorescence of an aromatic amino acid, tryptophan.

OBJECTIVE

To assess the impact of a novel, autofluorescence imaging (AFI) device on margin control for NMSCs before Mohs micrographic surgery (MMS) in an effort to decrease overall operating time.

METHODS

Before the initial stage of MMS, NMSCs were measured with a 2-mm margin as standard of care (normal margin). The tumor was then imaged with the AFI device. A 2-mm margin was drawn around the fluorescent area captured by the AFI device and was referred to as the camera margin. The tumor was excised based on the normal margin and evaluated on frozen histological section.

RESULTS

Imaging based on the AFI device resulted in appropriate recommendations for margin control in 8 of 11 tumors. Four of these tumors did not fluoresce and demonstrated a lack of tumor residuum on stage I specimen, as anticipated. There were no side effects from the AFI device.

CONCLUSION

This is an initial pilot study that supports the use of a novel, noninvasive imaging device to help with margin assessment before MMS. On optimization, this device has potential to extend applicability to surgical excisions for tumors that do not fulfill criteria for MMS.

Fluorescence and tracers in surgery: the coming future

The revolution that we are seeing in the world of surgery will determine the way we understand surgical approaches in coming years. Since the implementation of minimally invasive surgery, innovations have constantly been developed to allow the laparoscopic approach to go further and be applied to more and more procedures. In recent years, we have been in the middle of another revolutionary era, with robotic surgery, the application of artificial intelligence and image-guided surgery. The latter includes 3D reconstructions for surgical planning, virtual reality, holograms or tracer-guided surgery, where ICG-guided fluorescence has provided a different perspective on surgery. ICG has been used to identify anatomical structures, assess tissue perfusion, and identify tumors or tumor lymphatic drainage. But the most important thing is that this technology has come hand in hand with the potential to develop other types of tracers that will facilitate the identification of tumor cells and ureters, as well as different light beams to identify anatomical structures. These will lead to other types of systems to assess tissue perfusion without the use of tracers, such as hyperspectral imaging. Combined with the upcoming introduction of ICG quantification, these developments represent a real revolution in the surgical world. With the imminent implementation of these technological advances, a review of their clinical application in general surgery is timely, and this review serves that aim.

Skin erythema assessment techniques

Skin erythema may present owing to many causes. One of the common causes is prolonged exposure to sunrays. Other than sun exposure, skin erythema is an accompanying sign of dermatologic diseases, such as psoriasis and acne. Quantifying skin erythema in patients enables the dermatologist to assess the patient's skin health. Quantitative assessment of skin erythema has been the focus of several studies. The clinical standard for erythema evaluation is visual assessment; however, this standard has some deficiencies. For instance, visual assessment is subjective and ineffectual for precise color information exchange. To overcome these limitations, in the past three decades various methodologies have been developed in an attempt to achieve objective erythema assessments, such as diffuse reflectance spectroscopy and both optical and nonoptical systems. This review considers the studies published during the past three decades and discusses the performance, the mathematical tactics for computation, and the limited capabilities of erythema assessment techniques for cutaneous diseases. The achievements and limitations of the current techniques in erythema assessment are presented. The advantages and development trends of optical and nonoptical methods are presented to make the reader aware of the present technological advances and their potential for dermatological disease research.

WITHDRAWN: Interventions for photodamaged skin

This review has been withdrawn because a review author contravenes Cochrane's Commercial Sponsorship Policy. This policy ensures the independence of Cochrane reviews by making sure that there is no bias associated with commercial conflicts of interest in the conduct of Cochrane reviews. The author was employed by the biopharmaceutical company AstraZeneca and cannot say with certainty that the company did not produce or have any financial interest in the interventions in this review.

The editorial group responsible for this previously published document have withdrawn it from publication.

Appearance-based interventions to reduce ultraviolet exposure and/or increase sun protection intentions and behaviours: a systematic review and meta-analyses

OBJECTIVES

A systematic review and meta-analyses were conducted to identify and review research examining the impact of appearance-based interventions on sun protection intentions and/or ultraviolet (UV) exposure behaviour.

METHODS

A search of 16 databases including PsycARTICLES, Cochrane Library and Web of Knowledge was conducted to identify studies examining the impact of appearance-based interventions on reducing UV exposure and/or increasing sun protection intentions and behaviours. A total of 21 articles met the inclusion criteria, and these studies were subjected to a systematic review and meta-analyses to determine the effectiveness of the interventions.

RESULTS

Interventions used a variety of techniques including UV technology and photoaging information. Study design and outcome measures varied. The research indicated that appearance-based interventions have a positive effect on UV exposure and sun protection intentions and behaviour.

CONCLUSIONS

Findings suggest that interventions based on the appearance-damaging effects of UV exposure, and the positive effects of sun protection, may have a role in health promotion. It is concluded that there is a need for further research incorporating a wider range of participants, and using qualitative and mixed methods designs.

STATEMENT OF CONTRIBUTION

What is already known on the subject? Recreational exposure to ultraviolet (UV) radiation, are the primary causes of all melanomas, leading to skin cancer. A previous systematic review (Dodd & Forshaw, ) looking at the efficacy of appearance-focussed interventions in skin cancer prevention, suggested that there were significant effects for UV protection behaviour after such interventions. What does this study add? An up-to-date systematic review of studies that has carried out appearance-based interventions to reduce UV exposure and/or increase sun protection intentions and behaviours. A meta-analysis of data providing statistical evidence indicating that appearance-based interventions have a positive effect on UV exposure and sun protection intentions and behaviour.

Sun damage in ultraviolet photographs correlates with phenotypic melanoma risk factors in 12-year-old children

BACKGROUND

Ultraviolet (UV) photography has been used to motivate sun safety in behavioral interventions. The relationship between sun damage shown in UV photographs and melanoma risk has not been systematically investigated.

OBJECTIVE

To examine the relationship between severity of sun damage in UV photographs and phenotypic melanoma risk factors in children.

METHODS

UV, standard visible and cross-polarized photographs were recorded for 585 children. Computer software quantified sun damage. Full-body nevus counts, skin color by colorimetry, facial freckling, hair and eye color were collected in skin examinations. Demographic data were collected in telephone interviews of parents.

RESULTS

Among 12-year-old children, sun damage shown in UV photographs correlated with phenotypic melanoma risk factors. Sun damage was greatest for children who were non-Hispanic white and those who had red hair, blue eyes, increased facial freckling, light skin and greater number of nevi (all P values < .001). Results were similar for standard visible and cross-polarized photographs. Freckling was the strongest predictor of sun damage in visible and UV photographs. All other phenotypic melanoma risk factors were also predictors for the UV photographs.

LIMITATIONS

Differences in software algorithms used to score the photographs could produce different results.

CONCLUSION

UV photographs portray more sun damage in children with higher risk for melanoma based on phenotype. Therefore sun protection interventions targeting those with greater sun damage on UV photographs will target those at higher melanoma risk. This study establishes reference ranges dermatologists can use to assess sun damage in their pediatric patients.

Two fluorescent wavelengths, 440(ex)/520(em) nm and 370(ex)/440(em) nm, reflect advanced glycation and oxidation end products in human skin without diabetes

BACKGROUND

Advanced glycation end products (AGEs) and oxidation products (OPs) play an important role in diabetes complications, aging, and damage from sun exposure. Measurement of skin autofluorescence (SAF) has been promoted as a noninvasive technique to measure skin AGEs, but the actual products quantified are uncertain. We have compared specific SAF measurements with analytically determined AGEs and oxidative biomarkers in skin collagen and determined if these measurements can be correlated with chronological aging and actinic exposure.

METHODS

SAF at four excitation (ex)/emission (em) intensities was measured on the upper inner arm ("sun protected") and dorsal forearm ("sun exposed") in 40 subjects without diabetes 20-60 years old. Skin collagen from the same sites was analyzed by liquid chromatography-tandem mass spectrometry for three AGEs-pentosidine, carboxymethyllysine (CML), and carboxyethyllysine (CEL)-and the OP methionine sulfoxide (MetSO).

RESULTS

There was poor correlation of AGE-associated fluorescence spectra with AGEs and OP in collagen, with only pentosidine correlating with fluorescence at 370(ex)/440(em) nm. A little-studied SAF (440(ex)/520(em) nm), possibly reflecting elastin cross-links, correlated with all AGEs and OPs. Levels of CML, pentosidine, and MetSO, but not SAF, were significantly higher in sun-exposed skin. These AGEs and OPs, as well as SAF at 370(ex)/440(em) nm and 440(ex)/520(em) nm, increased with chronological aging.

CONCLUSIONS

SAF measurements at 370(ex)/440(em) nm and 335(ex)/385(em) nm, except for pentosidine, which correlated with fluorescence at 370(ex)/440(em), correlate poorly with glycated and oxidatively modified protein in human skin and do not reflect actinic modification. A new fluorescence measurement (440(ex)/520(em) nm) appears to reflect AGEs and OPs in skin.

Skin-lightening products revisited

Skin colour typology depends on the amount and location of its chromophores. Among them, eumelanins derived from 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI), and phaeomelanins are of utmost importance. These biomolecules result from the multi-step enzymatic and non-enzymatic conversion of tyrosine into melanins. Pigmentation disorders are multiple and depend on alterations in the density in active melanocytes, and on specific abnormalities of any of the complex melanogenesis mechanisms. This review presents some of the main skin-lightening agents with respect to their mechanisms of action and side-effects. Some of the novel compounds may lead to new perspectives in the fields of dermatology and cosmetology. The methods commonly used to assess efficacy of skin-lightening products rely on in vitro models including cell-free enzymatic assays, melanocyte cultures and reconstructed epidermis bioassays. Animal models have little relevance. By contrast, human testing with the support of instrumental evaluations is the most informative.

A randomized controlled trial of an appearance-focused intervention to prevent skin cancer

BACKGROUND

Skin cancer represents a significant health threat with over 1.3 million diagnoses, 8000 melanoma deaths, and more than $1 billion spent annually for skin cancer healthcare in the US. Despite findings from laboratory, case-control, and prospective studies that indicate a link between youthful indoor tanning (IT) and skin cancer, IT is increasing among US youth. Appearance-focused interventions represent a promising method to counteract these trends.

METHODS

A total of 430 female indoor tanners were randomized into intervention or no intervention control conditions. Intervention participants received an appearance-focused booklet based on decision-theoretical models of health behavior. Outcome variables included self-reports of IT behavior and intentions, as well as measures of cognitive mediating variables.

RESULTS

Normative increases in springtime IT rates were significantly lower (ie, over 35%) at 6-month follow-up in intervention versus control participants with similar reductions in future intentions. Mediation analyses revealed 6 cognitive variables (IT attitudes, fashion attitudes, perceived susceptibility to skin cancer and skin damage, subjective norms, and image norms) that significantly mediated change in IT behavior.

CONCLUSIONS

The appearance-focused intervention demonstrated strong effects on IT behavior and intentions in young indoor tanners. Appearance-focused approaches to skin cancer prevention need to present alternative behaviors as well as alter IT attitudes. Mediational results provide guides for strengthening future appearance-focused interventions directed at behaviors that increase risk of skin cancer.

Digital ultraviolet reflectance photography can be used to quantify improvements in photodamage

OBJECTIVE

Increasing attention has focused on the treatment and reversal of ultraviolet- induced photodamage. This study was designed to determine whether ultraviolet reflectance photography could quantify the clinical effects of erbium:YAG laser resurfacing on photoaged skin.

METHODS

Twenty patients (ages 46-67) with moderate to severe photodamage underwent dual-mode variable pulsed erbium:YAG laser facial resurfacing. Pretreatment and post-treatment evaluations at 3 and 6 months were performed clinically and photographically with white and ultraviolet reflectance photography.

RESULTS

Image conversion of the ultraviolet reflectance imaging data demonstrated an average of 36% and 42% reduction in photodamage at 3 and 6 months, respectively. This correlated well with the wrinkle reduction and correction of dyspigmentation observed in all patients following laser resurfacing. Histologic examination confirmed a thicker, more orderly epidermis and dermal collagen remodeling after treatment.

CONCLUSION

Reduction in photodamage using the dual-mode variable pulsed erbium:YAG laser can be quantitatively measured with ultraviolet reflectance photography using digital imaging. This model should prove useful in developing treatment regimens for photodamage.

Interventions for photodamaged skin

BACKGROUND

Photodamage describes skin changes such as fine and coarse wrinkles, roughness, freckles and pigmentation changes that occur as a result of prolonged exposure to the sun. Many treatments are available to reverse the damage, but it is unclear which work and at what cost in terms of unwanted side effects.

OBJECTIVES

To assess the effects of topically applied treatments, tablet treatments, laser and surgical procedures for photodamaged skin.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, Issue 1 2002, MEDLINE (1966-June 2002), EMBASE (1974-June 2002), Health Periodicals (1976-June 2002). We checked references of articles and communicated with authors and the pharmaceutical industry.

SELECTION CRITERIA

Randomised controlled trials which compared drug or surgical interventions with no treatment, placebo or another drug, in adults with mild, moderate or severe photodamage of the face or forearms.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed trial quality.

MAIN RESULTS

Thirty studies of variable quality were included. Eight trials showed that topical tretinoin cream, in concentrations of 0.02% or higher, was superior to placebo for participants with mild to severe photodamage on the face and forearms (although losses to follow-up were relatively high in most studies). For example, the relative risk of improvement for 0.05% tretinoin cream, compared to placebo (three studies), at 24 weeks, was 1.73 (95% confidence interval 1.39 to 2.14). This effect was not seen for 0.001% topical tretinoin (one study) or 0.01% (three studies). A dose-response relationship was evident for both effectiveness and skin irritation. One small within-patient study showed benefit from topical ascorbic acid compared with placebo. Tazarotene (0.01% to 0.1%) and isotretinoin (0.1%) both showed significant improvement over placebo for moderate photodamage (one study each). There is limited evidence (one trial), to show that the effectiveness of 0.05% tretinoin, is equivalent to the effects of 0.05% and 0.1% tazarotene. One small study showed greater improvement in upper lip wrinkles with CO2 laser technique compared to Baker's phenol chemical peel, at 6 months. Three small RCTs comparing CO2 laser with dermabrasion found no difference in wrinkle score at 4 to 6 months, suggesting that both methods are equally efficacious, but more erythema was reported with the laser. The effectiveness of other interventions such as hydroxy acids and natural polysaccharides was not clear.

AUTHORS' CONCLUSIONS

There is conclusive evidence that topical tretinoin improves the appearance of mild to moderate photodamage on the face and forearms, in the short term. However erythema, scaling/dryness, burning/stinging and irritation may be experienced initially. There is limited evidence that tazarotene and isotretinoin benefit patients with moderate photodamage on the face: both are associated with skin irritation and erythema. The effectiveness of other interventions remains uncertain.

Imaging the skin

Since the discovery of X-rays, the use of imaging technology has continued to play an important role in medicine. Technological advancements have led to the development of various imaging modalities, most of which have been used to image organs deep within the human body. More recently, attention has focused on the application of imaging technology for evaluation of the skin. A variety of techniques are currently being used to examine the skin and these include specialized photography, surface microscopy, ultrasound, laser Doppler perfusion imaging, confocal microscopy, and magnetic resonance imaging. These modalities can provide information that can assist in the management of skin problems. Although many of these techniques are still undergoing research, they are showing promise as useful clinical tools in dermatology.

Fiber optic probes for biomedical optical spectroscopy

Fiber optic probes are a key element for biomedical spectroscopic sensing. We review the use of fiber optic probes for optical spectroscopy, focusing on applications in turbid media, such as tissue. The design of probes for reflectance, polarized reflectance, fluorescence, and Raman spectroscopy is illustrated. We cover universal design principles as well as technologies for beam deflecting and reshaping.

Optical non-invasive approaches to diagnosis of skin diseases

A number of noninvasive approaches have been developed over the years to provide objective evaluation of the skin both in health and in disease. The advent of computers, as well as of lasers and photonics, has made it possible to develop additional techniques that were impossible a few years ago. These approaches provide the dermatologist with sensitive tools to measure the skin's condition in terms of physiologic parameters (e.g., color, erythema and pigmentation, induration, sebaceous and stratum corneum lipids, barrier function, etc.). Yet, a typical dermatologic diagnosis relies primarily on the trained eyes of the physician and to a lesser extent on information from other senses, such as touch and smell. The trained senses of the dermatologist backed by his/her brain form a powerful set of tools for evaluating the skin. The golden rule in diagnosis remains the histologic examination of a skin biopsy, a rather invasive method. These tools have served the profession well. The advent of ever faster and cheaper computers and of sensitive, inexpensive optical instrumentation of minimal dimensions provides the professional with the possibility of making objective measures of a number of skin parameters.

New photographic techniques for clinical evaluation of acne

Clinical evaluation of acne is usually based on direct visual assessment and ordinary flash photography, both of which are compromised by viewer subjectivity. It is difficult to accurately assess individual acne lesions and to observe early response to therapy. Standard flash photography has inherent limitations owing to the physics of light; it does not permit consistent visualization of subtle cutaneous characteristics like erythema or microcomedones, and it tends to blur distinctions between active inflammatory lesions and older hyperpigmented macules. Over the last decade there has been increasing interest in newer techniques aimed at increasing the accuracy and objectivity of acne evaluation. These include parallel-polarized light photography, cross (or perpendicular)-polarized light photography, videomicroscopy, and fluorescence photography. This article will review the advances of the past decade and summarize new techniques to evaluate acne lesions. Moreover, findings of a study that evaluated the course of individual acne lesions and the effects of adapalene gel 0.1% on inflammatory and non-inflammatory acne lesions will be viewed. In this study, the use of parallel-polarized and cross-polarized photography, in combination with videomicroscopy and sebum production measurement, provided objective, detailed information on the evolution of different variable acne lesions and their response to adapalene gel 0.1%. Adapalene treatment produced rapid resolution of inflammatory and non-inflammatory lesions, and inhibited formation of new lesions. Sebum secretion rates also declined during treatment. Use of the new assessment techniques proved to be a valuable, non-invasive and reliable method of assessing acne vulgaris and its response to treatment.

Aging and effects of ultraviolet A exposure may be quantified by fluorescence excitation spectroscopy in vivo

The fluorescence properties of skin chromophores such as tryptophan and collagen cross-links might be useful markers of aging and photoaging. As the fluorescence of pepsin-digestible collagen cross-links was found to increase with aging and decrease with photoaging we investigated the characteristics of this dependence. In vivo fluorescence excitation spectra (emission at 380 nm) of SKH hairless mouse model skin are characterized by two bands centered near 295 nm and 335 nm due, respectively, to epidermal tryptophan moieties and pepsin-digestible collagen cross-links. Several groups of hairless mice were followed over a period of 18 mo to document changes in skin fluorescence with aging. Other groups of animals were exposed to either broad band or narrowband ultraviolet A radiation to determine the effects of ultraviolet A exposure on the fluorescence of the dermal collagen cross-links and to determine an action spectrum for the induced changes. We also found that the intensity of pepsin-digestible collagen cross-links in vivo increases linearly with age and that the fluorescence of epidermal tryptophan decreases linearly with age. We found that the fluorescence of pepsin-digestible collagen cross-links decreases immediately following exposure to ultraviolet A whereas epidermal tryptophan fluorescence increases. Both changes were dose dependent but the increase in tryptophan fluorescence occurred exclusively in young animals (2--6 mo old). We found that the ultraviolet-induced fluorescence decrease of pepsin-digestible collagen cross-links is wavelength specific. The action spectrum for the ultraviolet A effect on the in vivo fluorescence of pepsin-digestible collagen cross-links shows a distinct maximum at 335 nm that corresponds to the maximum in the fluorescence excitation spectrum due to pepsin-digestible collagen cross-links. Our results seem to indicate that in vivo fluorescence of epidermal tryptophan moieties and collagen cross-links in the dermal matrix may serve as markers for skin aging, for photoaging, and for immediate assessment of exposure to ultraviolet A radiation.

Fluorescence excitation spectroscopy provides information about human skin in vivo

Fluorescence spectroscopy of human skin has the potential to provide useful morphologic and biochemical information. The endogenous fluorescence of human skin has been investigated in vivo on normal human volunteers as well as on patients with psoriasis and it was found that characteristic bands can be identified in the fluorescence spectra that are associated with specific skin fluorophores. One epidermal band (295 nm excitation, attributed to tryptophan) and two dermal bands (335 and 370 nm excitation, attributed to collagen cross-links) were consistently present in all fluorescence spectra. In addition, the fluorescence spectra obtained from lesions and nonlesional sites of psoriatic patients differed from those obtained from healthy volunteers and the hyperproliferative state of the lesions was characterized by a significantly larger signal at 295 nm excitation. These results indicate that fluorescence spectroscopy is a promising technique for the investigation of human skin in vivo.

Endogenous skin fluorescence includes bands that may serve as quantitative markers of aging and photoaging

Aging and photoaging cause distinct changes in skin cells and extracellular matrix. Changes in hairless mouse skin as a function of age and chronic UVB exposure were investigated by fluorescence excitation spectroscopy. Fluorescence excitation spectra were measured in vivo, on heat-separated epidermis and dermis, and on extracts of mouse skin to characterize the absorption spectra of the emitting chromophores. Fluorescence excitation spectra obtained in vivo on 6 wk old mouse skin had maxima at 295, 340, and 360 nm; the 295 nm band was the dominant band. Using heat separated tissue, the 295 nm band predominantly originated in the epidermis and the bands at 340 and 360 nm originated in the dermis. The 295 nm band was assigned to tryptophan fluorescence, the 340 nm band to pepsin digestable collagen cross-links fluorescence and the 360 nm band to collagenase digestable collagen cross-links fluorescence. Fluorescence excitation maxima remained unchanged in chronologically aged mice (34-38 wk old), whereas the 295 nm band decreased in intensity with age and the 340 nm band increased in intensity with age. In contrast, fluorescence excitation spectra of chronically UVB exposed mice showed a large increase in the 295 nm band compared with age-matched controls and the bands at 340 and 350 nm were no longer distinct. Two new bands appeared in the chronically exposed mice at 270 nm and at 305 nm. These reproducible changes in skin autofluorescence suggest that aging causes predictable alterations in both epidermal and dermal fluorescence, whereas chronic UV exposure induces the appearance of new fluorphores.