The background and philosophy behind daylight photodynamic therapy.

Conventional photodynamic therapy (PDT) is associated with side effects, primarily related to the waiting time between pretreatment with application of photosensitizer and illumination. Pain during illumination is a major issue for the patients and options for effective pain relief are limited. Post-treatment inflammation can often be severe and cause inconvenient down-time for the patients and their employers. To avoid the problems of pain and patients crowding in the clinic we eliminated red light treatment of high PpIX concentration and introduced illumination in daylight which may be performed at home. We also investigated if protoporphyrin IX (PpIX) could be activated continuously during its formation which might reduce pain and inflammation. Continuous activation of PpIX during its formation turned out to minimize pain as single PpIX molecules are activated continuously without accumulation of PpIX in the skin. PpIX molecules are formed in the mitochondria and the photodynamic effect only takes place in the mitochondria when continuously activated. This results primarily in apoptosis with little inflammation. Continuous activation of PpIX can be obtained by performing photodynamic therapy in daylight, as well as with daylight-emitting light sources of appropriate wavelengths. Use of daylight prevents the patients from crowding in the clinic. Daylight-PDT completely fulfils the purpose of minimizing pain and inflammation, as well as limiting the strain on the clinic treating the patients.

The half-life of 25(OH)D after UVB exposure depends on gender and vitamin D receptor polymorphism but mainly on the start level.

The 25-hydroxy vitamin D (25(OH)D) production caused by UVB exposure is usually underestimated as the concurrent degradation of 25(OH)D is not considered. Therefore, the decrease in 25(OH)D was investigated during a 7-week period in winter when ambient UVB is negligible. Twenty-two healthy Danish individuals (113 samples) participated and had a mean and steady maximal 25(OH)D start level of 132 nmol l-1 (range of 68-216 nmol l-1) due to long-term UVB treatment prior to this study. In this group with high 25(OH)D start levels, the decrease in 25(OH)D was best described by an exponential model. This suggests a quantitatively larger elimination of 25(OH)D at high 25(OH)D start levels. A linear model (logarithm of 25(OH)D) including personal start levels as intercepts and a slope influenced by gender and the vitamin D receptor gene polymorphism rs2228570 explained 87.8% of the observed variation. The mean half-life was 89 days with a difference in half-life of 120 days between a male with rs2228570 genotype GG (59 days) and a female with rs2228570 genotype AA/AG (179 days). Thus, these two parameters explained a large part of the observed inter-individual variation of 25(OH)D. Furthermore, the decrease was analysed in two groups with medium and low 25(OH)D start levels resulting in longer half-lives of 149 days and 199 days, respectively. The longer half-lives at lower 25(OH)D levels may be caused by storage mobilisation, changed catabolism or increased intestinal absorption.

Side effects from intense pulsed light: Importance of skin pigmentation, fluence level and ultraviolet radiation-A randomized controlled trial.

BACKGROUND AND OBJECTIVE: Intense pulsed light (IPL) is a mainstream treatment for hair removal. Side effects after IPL are known, but risk factors remain to be investigated. The objective of this study was to assess the contribution of skin pigmentation, fluence level, and ultraviolet radiation (UVR) on IPL-induced side effects. METHODS: The study was a blinded, randomized intra-individual controlled trial including 16 healthy subjects with Fitzpatrick Skin Types (FST) II-V. Three test areas were each divided into four sites, randomized to a single IPL exposure of 22, 34, 46 J/cm2 or triple stacking of 46 J/cm2 . Areas were subsequently randomized to no UVR or single solar-simulated UVR exposure of 3 Standard Erythema Dose at 30 minutes or 24 hours after IPL. Each area had a corresponding control, resulting in 15 treatment sites. Follow-up visits were scheduled up to 4 weeks after IPL. Outcome measures were: (i) blinded clinical skin reactions; (ii) objectively measured erythema and pigmentation; (iii) pain measured by visual analog scale (VAS); (iv) histology (H&E, Fontana-Masson); and (v) mRNA-expression of p53. RESULTS: Fifteen subjects with FST II-IV completed the protocol. IPL induced a wide range of skin reactions, including erythema (87% of subjects), purpura (27%), blisters (20%), edema (13%), crusting (13%), hyper- (60%), and hypopigmentation (20%). Darker skin pigmentation and increasing IPL fluence were determinants for IPL-induced side effects (P ≤ 0.002), while a single exposure of UVR did not exacerbate side effects (P ≥ 0.180). Clinical findings were confirmed objectively by reflectance spectrometry and qualitatively by histological changes in skin architecture, inflammatory infiltration, and pigmentation. Marker of cellular DNA damage, that is, p53, did not increase after IPL (P ≥ 0.24). CONCLUSIONS: Skin pigmentation and IPL fluence are major determinants of side effects after IPL exposure, while a single exposure to three SED of UVR at 30 minutes or 24 hours after IPL, does not amplify such side effects. Lasers Surg. Med. 49:88-96, 2017. © 2016 Wiley Periodicals, Inc.

Major inter-personal variation in the increase and maximal level of 25-hydroxy vitamin D induced by UVB.

Vitamin D influences skeletal health as well as other aspects of human health. Even when the most obvious sources of variation such as solar UVB exposure, latitude, season, clothing habits, skin pigmentation and ethnicity are selected for, variation in the serum 25-hydroxy vitamin D (25(OH)D) response to UVB remains extensive and unexplained. Our study assessed the inter-personal variation in 25(OH)D response to UVR and the maximal obtainable 25(OH)D level in 22 healthy participants (220 samples) with similar skin pigmentation during winter with negligible ambient UVB. Participants received identical UVB doses on identical body areas until a maximal level of 25(OH)D was reached. Major inter-personal variation in both the maximal obtainable UVB-induced 25(OH)D level (range 85-216 nmol l(-1), mean 134 nmol l(-1)) and the total increase in 25(OH)D (range 3-139 nmol l(-1), mean 48 nmol l(-1)) was found. A linear model including measured 25(OH)D baselines as personal intercepts explained 54.9% of the variation. By further including personal slopes in the model, as much as 90.8% of the variation could be explained. The explained variation constituted by personal differences in slopes thus represented 35.9%. Age, vitamin D receptor gene polymorphisms, height and constitutive skin pigmentation (a skin area not exposed to UVB) explained 15.1% of this variation. Despite elimination of most known external sources of variation, our study demonstrated inter-personal variation corresponding to an observed maximal difference of 136 nmol l(-1) in the total increase of 25(OH)D and 131 nmol l(-1) in the maximal level of 25(OH)D.

Ultraviolet radiation after exposure to a low-fluence IPL home-use device: a randomized clinical trial.

The prevailing advice is to avoid sun exposure after intense pulsed light (IPL) hair removal. However, no systematic evaluation of ultraviolet radiation (UVR) after IPL hair removal exits. Therefore, we investigated the occurrence of side effects in subjects receiving solar-simulated UVR after a low-fluence IPL treatment with a home-use device. Sixteen subjects with Fitzpatrick skin types (FST) II-V were enrolled. Three constitutive buttock blocks (4.4 × 6.4 cm) were each subdivided into four sites, randomized to one IPL exposure of 0, 7, 8, or 10 J/cm2 (spectral output 530-1100 nm). Blocks were randomized to no UVR or three standard erythema doses (SEDs) UVR either 30 min or 24 h after IPL. Follow-up visits were 48 h, 1 week, and 4 weeks after IPL. Outcome measures were (i) clinical skin reactions, (ii) reflectance measurements of erythema and pigmentation, and (iii) pain. Subjects with FST II-IV experienced no skin reactions up to 4 weeks after IPL, neither erythema, edema, blisters, crusting, textual, nor pigment changes. Reflectance confirmed no change in erythema and pigmentation (p ≥ 0.090). UVR exposure induced erythema and increased pigmentation. The combination of IPL and UVR induced skin reactions not different to responses from UVR (IPL-UVR vs. UVR, p ≥ 0.164). Pain was generally low (median 1, range 0-4) and correlated positively with fluence and pigmentation (Spearman's rho ≥ 0.394, p < 0.001). One subject with FST V experienced perifollicular hyperpigmentation after IPL and slightly more intense when exposed to UVR. A single UVR exposure of three SEDs either shortly or 1 day after low-fluence IPL causes no amplification of skin responses in constitutive skin of individuals with FST II-IV.

Sun and ski holidays improve vitamin D status, but are associated with high levels of DNA damage.

Skin cancer is caused by solar UVR, which is also essential for vitamin D production. DNA damage (thymine dimers: T-T dimers) and vitamin D (25(OH)D) synthesis are both initiated by solar UVB. We aimed to investigate the simultaneous adverse and beneficial effects of solar UVB exposure in holidaymakers. Sun-seekers and skiers (n=71) were observed over 6 days through on-site monitoring, personal diary entries, and recording of personal UVB exposure doses with electronic dosimeters. Urine and blood samples were analyzed for T-T dimers and 25(OH)D, respectively. The volunteers had a statistically significant increase in vitamin D. There were strong associations between UVB exposure and post-holiday levels of T-T dimers and vitamin D, as well as between post-holiday T-T dimers and vitamin D. We conclude that UVB-induced vitamin D synthesis is associated with considerable DNA damage in the skin. These data, on two major health predictors, provide a basis for further field studies that may result in better understanding of the risks and benefits of "real life" solar exposure. However, vitamin D status can be improved more safely through the use of vitamin D dietary supplements.

The role of natural and UV-induced skin pigmentation on low-fluence IPL-induced side effects: a randomized controlled trial.

BACKGROUND AND OBJECTIVES: The risk of adverse skin effects following light-based hair removal is greater in pigmented skin based on the theory of selective photothermolysis. Thus sunlight-induced pigment i.e., facultative pigmentation, increases the risk of adverse skin effects, perhaps disproportionately. The aim of this study was to evaluate the influence of constitutive and facultative skin pigmentation on low-fluence intense pulsed light (IPL)-induced adverse skin effects. STUDY DESIGN/MATERIALS AND METHODS: Twenty-one subjects with Fitzpatrick skin type II-IV were enrolled. Two buttock blocks were randomized to receive 0 or 8 solar simulated ultraviolet radiation (UVR) exposures of consecutively increasing Standard Erythema Doses (2-4 SED). Each block was subdivided into four sites, randomized to receive IPL of 0, 7, 8, or 10 J/cm(2) , once a week for 3 weeks. Biopsies were taken 16-24 hours after the first IPL exposure and subjects were seen 1 and 4 weeks after the last IPL exposure. Outcome measures were: (i) skin reactions, (ii) pain, (iii) mRNA expression of pigment-markers microphthalmia-associated transcription factor (MITF) and pro-opiomelanocortin (POMC), and (iv) clinical appearance of biopsy wounds. RESULTS: Skin pigmentation increased after UVR (baseline median 13.8%, after UVR 28.1%, P = 0.0001) in all skin types. Subjects reported low pain intensities (median 1.5, scale 0-10) and experienced transient erythema immediately after IPL exposure. No persistent erythema, blisters, crusting, textual, or pigment changes were observed. The risk of erythema and pain intensities increased with IPL dose and skin pigmentation (P < 0.03). There was no difference in pain or skin reactions in skin with similar degree of natural and facultative pigmentation (P ≥ 0.104). Expression of cellular pigment-markers was not influenced by IPL exposure, neither in constitutive nor in facultative pigmented skin. Clinical appearance of biopsy wounds was unaffected by IPL exposure. CONCLUSION: The prevalence and intensity of low-fluence IPL-induced adverse skin effects depended on IPL dose and skin pigmentation regardless of the origin, i.e., constitutive versus UV induced.

Low levels of vitamin D are associated with increased mortality in patients attending a university hospital in Denmark.

INTRODUCTION: Increased mortality in patients with low serum concentrations of S-25(OH)D has been described, though no causal relationship has been shown. The aim of this cohort study was to investigate the possible association between S-25(OH)D status and all-cause mortality in 5,147 patients attending a university hospital in Denmark from 2003-2008. METHODS: Serum was analyzed for ionized calcium (S-Ca(2+)), parathyroid hormone (S-PTH) and S-25(OH)D. Kaplan-Meier curves were used to analyze the association between S-25(OH)D quartiles, S-PTH-quartiles and all-cause mortality. Cox regression analyzed associations of age, gender, concentrations of ionized calcium, S-PTH and S-25(OH)D with all-cause mortality. RESULTS: Log rank tests for both S-25(OH)D and S-PTH quartiles showed a significant difference across the quartiles. The Cox regression analysis showed a hazard ratio (HR) for death of 1.02 (95% CI: 1.01; 1.03) for S-PTH per pmol/L increase, 1.07 (95% CI: 1.05; 1.10) for S-25(OH)D per 10 nmol/L decrease and 0.54 (95% CI: 0.24; 1.20) for S-Ca(2+) per mmol/L increase. DISCUSSION: This study supports growing evidence, that low serum concentrations of 25(OH)D are associated with an increased all-cause mortality; however the nature of the study prevents the finding of a causal relationship. In the Cox regression analysis S-25(OH)D concentrations in the blood were inversely associated with all-cause mortality. Prospective controlled studies are needed to confirm a causal relationship between low S-25(OH)D concentrations and mortality.

MDM2 inhibitor nutlin-3a induces apoptosis and senescence in cutaneous T-cell lymphoma: role of p53.

P53 is rarely mutated in cutaneous T-cell lymphoma (CTCL) and is therefore a promising target for innovative therapeutic approaches. Nutlin-3a is an inhibitor of MDM2 (human homolog of murine double minute 2), which disrupts its interaction with p53, leading to the stabilization and activation of p53. To investigate the potential therapeutic use of nutlin-3a in CTCL, we screened CTCL lines Hut-78, SeAx, MyLa2000, Mac1, and Mac2a by measuring p53 levels after nutlin-3a treatment. In MyLa2000, Mac1, and Mac2a, we observed the increase in p53, indicating the fully functional p53. In the remaining cell lines, P53 mutation analysis identified a homozygous nonsense mutation (R196Stop in Hut-78) and a homozygous missense mutation (G245S in SeAx). In MyLa2000, Mac1, and Mac2a carrying wild-type P53, nutlin-3a induced apoptosis and senescence demonstrated by permanent G0/G1 cell-cycle block and expression of the senescence-associated ß-galactosidase. This effect was abolished in cells in which p53 was silenced by small interfering RNA. Sézary cells lack functional p53 and were resistant to nutlin-3a. However, nutlin-3a potentiated the efficacy of conventional chemotherapeutics not only in cells with intact p53 but also in Hut-78, SeAx, and Sézary cells. Thus, targeting p53 by nutlin-3a may constitute a therapeutic approach in CTCL because of increased apoptosis and senescence of tumor cells.

Vitamin D production after UVB exposure depends on baseline vitamin D and total cholesterol but not on skin pigmentation.

UVB radiation increases serum vitamin D level expressed as 25-hydroxyvitamin-D(3) (25(OH)D), but the influence of skin pigmentation, baseline 25(OH)D level, and total cholesterol has not been well characterized. To determine the importance of skin pigmentation, baseline 25(OH)D level, and total cholesterol on 25(OH)D production after UVB exposure, 182 persons were screened for 25(OH)D level. A total of 50 participants with a wide range in baseline 25(OH)D levels were selected to define the importance of baseline 25(OH)D level. Of these, 28 non-sun worshippers with limited past sun exposure were used to investigate the influence of skin pigmentation and baseline total cholesterol. The participants had 24% of their skin exposed to UVB (3 standard erythema doses) four times every second or third day. Skin pigmentation and 25(OH)D levels were measured before and after the irradiations. Total cholesterol was measured at baseline. The increase in 25(OH)D level after UVB exposure was negatively correlated with baseline 25(OH)D level (P<0.001) and positively correlated with baseline total cholesterol level (P=0.005), but no significant correlations were found with constitutive or facultative skin pigmentation. In addition, we paired a dark-skinned group with a fair-skinned group according to baseline 25(OH)D levels and found no differences in 25(OH)D increase after identical UVB exposure.

Skin pigmentation kinetics after exposure to ultraviolet A.

Multiple exposures to ultraviolet radiation (UVR) are the norm in nature and phototherapy. However, studies of the kinetics of pigmentation following UVA exposure have included only fair-skinned persons. The aim of this study was to investigate steady-state pigmentation and fading in 12 Scandinavians and 12 Indians/Pakistanis after 6 and 12 exposures on the back using broadband UVA and UVA1 with equal sub-minimal melanogenic doses (individually predetermined). Pigmentation was measured by skin reflectance at 555 and 660 nm. The UV dose to minimal pigmentation was higher in dark-skinned persons after a single broadband UVA exposure, but independent of pigmentation/skin type after single and multiple UVA1 exposures. To elicit minimal melanogenic doses after 6 and 12 exposures, every dose is lowered by a factor of 2 and 3, respectively, but the cumulative dose increases three- and four-fold, respectively. The absolute increase in pigmentation was independent of pre-exposure pigmentation; therefore the percentage increase in pigmentation was higher in fair-skinned subjects. The absolute increase in pigmentation was higher and it took 2-3 days longer to reach steady-state after 12 UV exposures compared with 6 UV exposures. Days to steady-state pigmentation and fading were independent of pre-exposure pigmentation, and fading took 5-6 months. Comparing data from a narrowband UVB source and a Solar Simulator, it was shown that pigmentation built up faster and increased more after 12 UVA exposures (16 days) than with the Solar Simulator (21 days).

Immediate whealing urticaria in red light exposed areas during photodynamic therapy.

One of the recommended first-line treatments for basal cell carcinomas, actinic keratoses and Bowen's disease is photodynamic therapy. Commonly associated side- effects include pain and phototoxicity. Histamine release is a part of this reaction, but whealing urticaria follow noting photodynamic therapy has only been reported by the manufacturer. The aim of this study was to investigate the prevalence of immediate whealing urticaria in exposed areas during photodynamic therapy with topical methylester aminolevulinate and red light. Patients who developed immediate whealing urticaria during photodynamic therapy were prospectively registered in the period from 1 March 2002 to 14 May 2007. Twelve out of 1353 patients (0.9%) treated with photodynamic therapy developed immediate whealing urticaria and itch during red light illumination, which had not been experienced during previous sessions. Urticaria occurred in 3.8% of patients who had received more than 7 sessions of photodynamic therapy. Prophylactic use of systemic antihistamines reduced itch and whealing, permitting photodynamic therapy sessions to be continued.

Skin pigmentation kinetics after UVB exposure.

There have been few previous studies of the kinetics of pigmentation following ultraviolet B (UVB) exposure, and these have included only fair-skinned persons. The current study investigated pigmentation increase to steady state and fading in 12 Scandinavians and 12 Indians/Pakistanis. Over a period of 3 weeks the subjects were UV-irradiated 6 times on the right side of the back and 12 times on the left side using a Solar Simulator and narrowband UVB with equal sub-Minimal Melanogenesis Doses (individually predetermined). Pigmentation was measured from skin remittance at 555 nm and 660 nm (allowing correction for erythema). The absolute pigmentation increase was independent of pre-exposure pigmentation, therefore the percentage pigmentation increase was higher in fair-skinned volunteers. The UV dose to minimal pigmentation was higher in darker-skinned persons for single and multiple UV exposures for both UV sources. Going from a single exposure to 6 and 12 exposures, the required dose to minimal pigmentation was reduced by factors of 2 and 3, respectively, for both UV sources, thus reducing the risk of sunburn, but the cumulative dose increased 3- and 4-fold, respectively. This result was independent of skin type and pre-exposure pigmentation. Fading took 4-5 months and was not related to frequency of UV exposure or to ethnic origin.

Topical corticosteroids in the treatment of acute sunburn: a randomized, double-blind clinical trial.

OBJECTIVE: To examine the effect of topical corticosteroid treatment on acute sunburn. DESIGN: Randomized, double-blind clinical trial. SETTING: University dermatology department. PATIENTS: Twenty healthy volunteers with Fitzpatrick skin types I (highly sensitive, always burns easily, tans minimally) through III (sun-sensitive skin, sometimes burns, slowly tans to light brown). INTERVENTION: Seven 34-cm(2) areas were marked on the upper aspect of the back of each participant. An untreated area was tested to determine UV sensitivity. Two areas were treated with excess amounts (2 mg/cm(2)) of either a moderate-potency corticosteroid or a high-potency corticosteroid 30 minutes before UV-B exposure as controls. Six or 23 hours after exposure to radiation, the remaining areas were treated with the 2 corticosteroid preparations. MAIN OUTCOME MEASURES: The sunburn improvement factor (SIF) was determined by the following equation: SIF = MED (minimal erythema dose) on treated skin/MED on nontreated skin. An SIF greater than 1 indicated an effect of topical corticosteroids in sunburn relief. RESULTS: The SIFs in the areas treated with either topical corticosteroid 30 minutes before UV-B exposure or high-potency corticosteroid 6 hours after UV-B exposure were significantly different from SIFs in areas that received no treatment (SIF 1.1-1.7; P < .05). Only the median SIF of 1.7 in the areas treated with high-potency corticosteroid 30 minutes before UV-B exposure was clinically relevant. The areas treated 23 hours after UV-B exposure and the areas treated with a moderate-potency corticosteroid 6 hours after UV-B exposure showed no significant reduction in redness. CONCLUSION: Treatment with topical moderate-potency or high-potency corticosteroids does not provide a clinically useful decrease in the acute sunburn reaction when applied 6 or 23 hours after UV exposure.

Instrumental assessment of atopic eczema: validation of transepidermal water loss, stratum corneum hydration, erythema, scaling, and edema.

BACKGROUND: Quantification of skin diseases can be carried out in many ways. Clinical scores are widely used in atopic eczema (AE), and noninvasive instruments are a relevant supplement. OBJECTIVE: Our purpose was to validate 5 noninvasive instruments in quantification of AE severity. METHODS: In all, 101 patients with AE and 30 control subjects were assessed twice in a clinical cross-sectional examination. Assessment of transepidermal water loss, stratum corneum hydration, erythema, scaling, and subepidermal edema was assessed on 3 predetermined skin sites. RESULTS: The methods discriminated among various severity degrees and correlated significantly with objective assessment of disease severity. High correlations were found among instruments assessing acute symptoms of AE. Threshold values for transepidermal water loss and capacitance were found. LIMITATIONS: No gold standard exists for severity assessment of atopic eczema. Therefore, the methods used cannot be validated in relation to such a standard. Furthermore, atopic eczema is a generalized disease and the methods used assess target lesions. By assessing target lesions, information about the disease is reduced. CONCLUSION: Noninvasive instruments are valuable in quantification of disease severity in a mixed group of patients with active AE. Assessment with ultrasound has contributed new information about the pathophysiology in AE.

Real-time spatial compound ultrasound imaging of skin.

PURPOSE: The aim of our study was to evaluate the potential of real-time spatial compound imaging (RTSCI) in dermatology. MATERIALS AND METHODS: An ATL 5000 SonoCT equipped with compact linear 15-7 MHz and linear 12-5 MHz transducers was obtained for skin visualization in a group of dermatological patients with various skin diseases. RESULTS: Thirty-four people participated: 21 patients with various skin diseases and 13 persons with normal skin. The mean age was 43.4 years. For many diseases, RTSCI gave useful information about the lesional structure, thickness and relationship with surrounding structures. CONCLUSION: RTSCI allows objective, accurate, noninvasive and easy measurements of several parameters of skin morphology. It is useful in clinical trials, for evaluation of the effects of therapy, for preoperative evaluation of dermatological lesions, and enables visualization of subclinical and deep lesions, giving physicians the possibility of starting treatment before disease intensity increases. However, even such highly advanced ultrasound cannot completely substitute the clinical dermatological approach and the occasional need for histological diagnosis. This new method may, however, become an important adjunct method for the study of skin lesions.

Ultrasonido de alta resolucion (15 MHz) en el estudio de la u¤a psoriatica / High resolution ultrasound in the study of psoriatic nail

Antecedentes. La Psoriasis es una enfermedad frecuente en la practica dermatológica. En EE.UU., 7 millones de personas (2-3por ciento) la padecen. El 5 por ciento de los pacientes con psoriasis ungueal no tienen manifestaciones cutáneas. Entre 10-20 por ciento de los pacientes con psoriasis cutanea tienen artritis psoriatica. De los pacientes con artritis psoriatica, el 53-86 por ciento presentan compromiso ungueal. Objetivo. Estudiar los cambios visibles al ultrasonido de alta resolución, en la u¤a de los pacientes psoriaticos. Material y metodo. Se utilizo equipo de ultrasonido Philips ATL 5000 equipado con SonoCT, XRES, campo de visión extendida y transductores de 15-7 MHz y 12-5 MHz. Se estudiaron 15 pacientes, 9 controles normales y 6 psoriaticos con compromiso ungueal. Mujeres n=9 y hombres n=6, promedio de edad 47,7 a¤os. Se exploraron las 2 manos en todos los pacientes (150 u¤as) y se midieron en cada paciente las distancias entre ambas placas ungueales como también entre la placa ungueal ventral y el margen óseo de la falange distal en la u¤a del dedo indice derecho. Resultados. Se describe la anatomia ultrasonografica normal de la u¤a y cuatro patrones de alteraciones visibles en el compromiso por psoriasis que incluyen: compromiso focal hipere-cogenico de la placa ventral sin compromiso de placa dorsal, perdida de definición de la placa ventral con placa dorsal indemne, ondulación de ambas placas y perdida de definición de ambas placas. Se encontró una diferencia significativa (p= 0.02) entre el promedio de distancia placa ventral ungueal y margen óseo de la falange distal para u¤as normales (1,5 mm) y para psoriasis (3,0 mms). Conclusión: El ultrasonido de alta resolución permite un estudio no invasivo de la u¤a, describiendo su anatomia y cambios morfológicos en pacientes normales y psoriaticos con compromiso ungueal. Ello puede ser útil en la monitorización de los efectos del tratamiento de psoriasis en sus distintas mani-festaciones, ya que existen cambios imperceptibles en su magnitud y ubicación para el clinico, que pueden observarse sin esperar el recambio ungueal total. Las diferencias de distancia entre las placas de la u¤a, incluyendo la distancia con el margen óseo de la falange distal, en los pacientes normales y psoriaticos, en nuestro conocimiento, no han sido previamente publicadas.