Effects of air pollution on the skin: A review.

The increase in air pollution over the years has had major effects on the human skin. Various air pollutants such as ultraviolet radiation, polycyclic aromatic hydrocarbons, volatile organic compounds, oxides, particulate matter, ozone and cigarette smoke affect the skin as it is the outermost barrier. Air pollutants damage the skin by inducing oxidative stress. Although human skin acts as a biological shield against pro-oxidative chemicals and physical air pollutants, prolonged or repetitive exposure to high levels of these pollutants may have profound negative effects on the skin. Exposure to ultraviolet radiation has been associated with extrinsic skin aging and skin cancers. Cigarette smoke contributes to premature aging and an increase in the incidence of psoriasis, acne and skin cancers. It is also implicated in allergic skin conditions such as atopic dermatitis and eczema. Polyaromatic hydrocarbons are associated with extrinsic skin aging, pigmentation, cancers and acneiform eruptions. Volatile organic compounds have been associated with atopic dermatitis. Given the increasing levels of air pollution and its detrimental effects on the skin, it is advisable to use strategies to decrease air pollution.

Photodermatoses in India.

Photodermatoses are a group of disorders resulting from abnormal cutaneous reactions to solar radiation. They include idiopathic photosensitive disorders, drug or chemical induced photosensitivity reactions, DNA repair-deficiency photodermatoses and photoaggravated dermatoses. The pathophysiology differs in these disorders but photoprotection is the most integral part of their management. Photoprotection includes wearing photoprotective clothing, applying broad spectrum sunscreens and avoiding photosensitizing drugs and chemicals.

Solar ultraviolet radiation induces biological alterations in human skin in vitro: relevance of a well-balanced UVA/UVB protection.

Cutaneous damages such as sunburn, pigmentation, and photoaging are known to be induced by acute as well as repetitive sun exposure. Not only for basic research, but also for the design of the most efficient photoprotection, it is crucial to understand and identify the early biological events occurring after ultraviolet (UV) exposure. Reconstructed human skin models provide excellent and reliable in vitro tools to study the UV-induced alterations of the different skin cell types, keratinocytes, fibroblasts, and melanocytes in a dose- and time-dependent manner. Using different in vitro human skin models, the effects of UV light (UVB and UVA) were investigated. UVB-induced damages are essentially epidermal, with the typical sunburn cells and DNA lesions, whereas UVA radiation-induced damages are mostly located within the dermal compartment. Pigmentation can also be obtained after solar simulated radiation exposure of pigmented reconstructed skin model. Those models are also highly adequate to assess the potential of sunscreens to protect the skin from UV-associated damage, sunburn reaction, photoaging, and pigmentation. The results showed that an effective photoprotection is provided by broad-spectrum sunscreens with a potent absorption in both UVB and UVA ranges.

Need for a well-balanced sunscreen to protect human skin from both Ultraviolet A and Ultraviolet B damage.

Skin exposure to sunlight can cause many adverse effects. It is now recognized that both Ultraviolet A (UVA) and UVB wavelengths are responsible for the detrimental effects of solar radiation on skin. With our increasing knowledge on the harmful effects of UVA, the need for effective, well-balanced photoprotection has become more crucial. Numerous clinical studies showed that well-balanced sunscreen, with a SPF/UVAPF ratio ≤ 3, provide the most effective protection against pigmentation (especially on dark skin), DNA damage, UV-induced skin immunosuppression and photodermatoses. The calculation of UVA protection required in Asia revealed its particular importance in India, and gives clear evidence that the SPF value alone is not sufficient to evaluate the efficacy of a sunscreen.

The development of efficient sunscreens.

Skin exposure to acute or repetitive ultraviolet light induces risks which are now well identified. An efficient photoprotection is thus required for both UVB and UVA radiation. In particular, increasing evidence of the detrimental effects of UVA on skin has led to the development of a new generation of sunscreens that provide effective protection throughout the whole UV radiation spectrum. Many new UV filters have been introduced in the last decade, particularly UVA filters, with improved efficacy and safety. Sunscreen filters must be carefully combined to achieve esthetically pleasing products offering photostable and well-balanced photoprotection.

Cutaneous solar ultraviolet exposure and clinical aspects of photodamage.

Solar ultraviolet (UV) radiation reaching the earth is a combination of UVB (290-320 nm) and UVA (320-400 nm) wavelengths. Since UVA is less energetic than UVB, UVB has long been thought to be the factor responsible for the damaging effects of solar radiation. But with modern tools such as in vitro models, it has been proven that UVA plays a major role. The objective of this review is to show how skin may be exposed to UV light and to highlight the clinical aspects of UV-induced skin damages with the respective contribution of UVB or UVA. Even if UVA is less energetic than UVB, it is more abundant and penetrates deeper into the skin, reaching as far as the dermis. Various factors also influence skin exposure to UV light: the latitude, season, and time of the day. Acute as well as chronic sun exposure induces short- and long-term clinical damages. Erythema and pigmentation are immediate responses of normal human skin exposed to UV radiation. The long-term effects are photoaging and photocarcinogenesis. In particular, UVA appears to play a major role in the deterioration of dermal structure leading to the photoaged appearance of the skin.

Facial melanoses: Indian perspective.

Facial melanoses (FM) are a common presentation in Indian patients, causing cosmetic disfigurement with considerable psychological impact. Some of the well defined causes of FM include melasma, Riehl's melanosis, Lichen planus pigmentosus, erythema dyschromicum perstans (EDP), erythrosis, and poikiloderma of Civatte. But there is considerable overlap in features amongst the clinical entities. Etiology in most of the causes is unknown, but some factors such as UV radiation in melasma, exposure to chemicals in EDP, exposure to allergens in Riehl's melanosis are implicated. Diagnosis is generally based on clinical features. The treatment of FM includes removal of aggravating factors, vigorous photoprotection, and some form of active pigment reduction either with topical agents or physical modes of treatment. Topical agents include hydroquinone (HQ), which is the most commonly used agent, often in combination with retinoic acid, corticosteroids, azelaic acid, kojic acid, and glycolic acid. Chemical peels are important modalities of physical therapy, other forms include lasers and dermabrasion.

[Antistress cross-protection of UV irradiated yeast cells with participation of extracellular peptide factors].

Antistress effect of extracellular peptides on UV irradiated yeast of different phylogenetic groups was studied. Yeast from different ecotopes and taxonomic groups exposed to UV radiation of a lethal intensity showed a protective effect and reactivating effect with participation of extracellular peptides. The highest protective activity was found in peptide reactivation factors (RFs) of bakery yeast-Saccharomyces cerevisiae, Kluyveromyces fragilis, and Candida utilis; the highest reactivating activity was exhibited by factors of the above-mentioned cultures and Debariomyces hansenii. Cross-protective and reactivating effects of RFs of yeast belonging to different taxonomic groups were demonstrated. Cross-protection increased two to three times after preexposure of reactivation factors to UV light (activation) in contrast to their reactivating effect.

Evaluation of photopatch test allergens for Indian patients of photodermatitis: preliminary results.

BACKGROUND: There is a strong need to develop a photopatch test tray suitable for Indian patients of photodermatitis as European/Scandinavian photopatch test trays may not be wholly relevant for them. AIM: We carried out this study using photoallergens relevant in the Indian context to determine their relevance in patients of photodermatitis. METHODS: Thirty patients (M:F, 23:7) between 19 and 76 years of age of photodermatitis and 10 controls were patch- and photopatch tested with 20 common photoallergens. In addition, the patients were also (photo) patch tested with articles of daily use as and when these were suspected to be the cause. RESULTS: Forty-three positive reactions to one or more antigens were seen in 22 (74%) patients. Fourteen positive photopatch tests to seven allergens were observed in 10 (33%) patients, and nine (30%) of them had a definite relevance. The most common contact allergen was fragrance mix (FM) (30%), followed by p-phenylenediamine (20%) and Parthenium hysterophorous (17%). The definite relevance of the patch- and photopatch tests could be correlated in 47% of these patients. CONCLUSIONS: FM is the most common contact and photocontact allergen among the various photopatch test antigens. Although differences in technique and evaluation make direct comparison between different centers difficult, still photopatch testing remains an integral part and gold standard for the work-up of the photosensitive patients.

UVB suscetibilidade como fator de risco para o desenvolvimento da hanseníase virchowiana / UVB susceptibility as a risk factor to the development of lepromatous leprosy

FUNDAMENTOS: A radiação ultravioleta B (RUVB) é o mais importante fator ambiental capaz de modificar a função imunológica da pele humana. OBJETIVO: estudar a associação entre o fenótipo de suscetibilidade ou resistência à radiação RUVB e as formas polares da hanseníase. MATERIAL E MÉTODOS: foram avaliados 38 pacientes com hanseníase virchowiana (MHV) e 87 pacientes com hanseníase tuberculoide (MHT) de acordo com a classificação de Ridley e Jopling (1966). Todos os pacientes foram submetidos ao teste para determinação do fenótipo de suscetibilidade ou resistência à RUVB por meio da aplicação de um disco de dinitroclorobenzeno (DNCB) a 2 por cento em uma área de pele previamente irradiada com duas vezes a dose eritematosa mínima (DEM). Após 21 dias, outra aplicação de um disco similar de DNCB a 0,05 por cento na região escapular (área não exposta à RUVB) foi realizada para avaliar se houve sensibilização, com leitura após 48 horas. Os pacientes que apresentaram reação positiva ao DNCB foram considerados UVB-resistentes e o oposto foi considerado para aqueles que não apresentaram resposta (UVB-suscetíveis). RESULTADOS: A frequência de UVB-suscetíveis foi de 63,2 por cento (24 pacientes) no grupo MHV e 34,4 por cento (30 pacientes) no grupo MHT (OR = 3,26; IC = 1,36-7,87; x² = 7,73; p = 0,005). CONCLUSÃO: Os resultados sugerem que a UVB-suscetibilidade é um fator de risco para o desenvolvimento da MHV.

BACKGROUNDS: Ultraviolet radiation B (UVRB) is the most important environmental factor capable of altering the immune function of human skin. OBJECTIVE: To evaluate the association of the phenotypes of susceptibility or resistance to ultraviolet radiation B (UVRB) and the polar forms of leprosy. MATERIAL AND METHODS: We evaluated 38 patients with lepromatous leprosy (LL) and 87 patients with tuberculoid (TT) leprosy, according to the classification by Ridley and Jopling (1966). All the patients were submitted to a test to determine the phenotypes of susceptibility or resistance to UVRB through the application of a 2 percent dinitrochlorobenzene (DNCB) disc to a previously irradiated area with twice the minimal erythema dose (MED). After 21 days, a similar disc soaked in 0.05 percent DNCB was applied to the scapular area (unexposed to UVRB) to check for sensitiveness, with reading of the results after 48 hours. The patients that showed a positive reaction to DNCB were considered resistant (UVB-R) and those who did not show any reaction were considered susceptible (UVB-S). RESULTS: The frequency of UVB-S individuals was 63.2 percent (24 patients) in the LL group and 34.4 percent (30 patients) in the TT group (OR=3.26; IC=1.36 - 7.87; x²=7.73; p=0.005). CONCLUSION: Our results suggest that UVB-susceptibility is a risk factor to the development of lepromatous leprosy (LL).

Narrowband ultraviolet B in the treatment of psoriasis: the journey so far!

Ever since artificial TL-01 lamps were developed, narrowband ultraviolet B (NBUVB) has gained giant strides in dermatology. Psoriasis is one of the common indications for the use of NBUVB in present day dermatology. We discuss here the evolution of NBUVB, its mechanism of action pertaining to psoriasis, indications and contraindications, dosimetry, complications of NBUVB while being used in patients with psoriasis, its merits and demerits in comparison with broadband UVB and psoralen+UVA (PUVA), and recent developments in the delivery system of NBUVB.

UVB susceptibility as a risk factor to the development of lepromatous leprosy.

BACKGROUNDS: Ultraviolet radiation B (UVRB) is the most important environmental factor capable of altering the immune function of human skin. OBJECTIVE: To evaluate the association of the phenotypes of susceptibility or resistance to ultraviolet radiation B (UVRB) and the polar forms of leprosy. MATERIAL AND METHODS: We evaluated 38 patients with lepromatous leprosy (LL) and 87 patients with tuberculoid (TT) leprosy, according to the classification by Ridley and Jopling (1966). All the patients were submitted to a test to determine the phenotypes of susceptibility or resistance to UVRB through the application of a 2% dinitrochlorobenzene (DNCB) disc to a previously irradiated area with twice the minimal erythema dose (MED). After 21 days, a similar disc soaked in 0.05% DNCB was applied to the scapular area (unexposed to UVRB) to check for sensitiveness, with reading of the results after 48 hours. The patients that showed a positive reaction to DNCB were considered resistant (UVB-R) and those who did not show any reaction were considered susceptible (UVB-S). RESULTS: The frequency of UVB-S individuals was 63.2% (24 patients) in the LL group and 34.4% (30 patients) in the TT group (OR=3.26; IC=1.36 - 7.87; x(2)=7.73; p=0.005). CONCLUSION: Our results suggest that UVB-susceptibility is a risk factor to the development of lepromatous leprosy (LL).

Occurrence of plant sensitivity among patients of photodermatoses: a control-matched study of 156 cases from New Delhi.

BACKGROUND: Photodermatitis is an abnormal response to ultraviolet radiation (UVR). The photoallergic contact dermatitis caused by plant allergens is a serious cause of morbidity in India. Airborne contact dermatitis is the classical presentation of plant-induced dermatosis, which may become difficult to differentiate from chronic actinic dermatitis in chronic cases. The rapid growth of parthenium weed in India and its ill effects on the population make it important to detect all cases of parthenium sensitivity, which in some cases might simulate photodermatitis. AIMS: This study aims to detect the occurrence of plant sensitivity and photosensitivity in idiopathic-acquired photodermatoses, airborne contact dermatitis and general population taken as controls. METHODS: One hundred and fifty six consecutive patients suffering from polymorphic light eruption (PMLE), chronic actinic dermatitis (CAD) and airborne contact dermatitis (ABCD) were enrolled in the study over a period of three years (June 2004 to May 2007). An equal number of age and sex matched healthy subjects were enrolled in the study as controls. All the patients were subjected to detailed history taking, clinical examination and histopathological examination for diagnosis. Patch and photopatch testing were perfomed in all the patients and healthy controls for detection of allergic and photoallergic reactions to parthenium, xanthium and chrysanthemum plant antigens and control antigens. RESULTS: Out of 156 patients enrolled in the study, 78 (50%) had CAD, 67 (42.9%) had PMLE and 11 (7.05%) had ABCD. The occurrence of parthenium/xanthium allergy and photoallergy, either to parthenium or both was most commonly found in ABCD (72.7%), followed by CAD (32%). In PMLE 4.5% cases showed photoallergy. Only 1.9% in the control group showed sensitivity to parthenium and xanthium. CONCLUSION: This study indicates that parthenium (and possibly xanthium) may act as important environmental factors in the initiation and perpetuation of not only ABCD but of CAD as well. Photoexacerbation to UVA at positive parthenium/xanthium sensitivity sites in ABCD and CAD indicates that ABCD with photosensitivity to compositae can lead to CAD.

Determination of minimal erythemal dose for narrow band-ultraviolet B radiation in north Indian patients: comparison of visual and Dermaspectrometer readings.

BACKGROUND: Minimal erythemal dose (MED) for narrow band-ultraviolet B radiation (NB-UVB) varies with race and skin type. The aim was to estimate the MED for NB-UVB and compare visual readings with those from a Dermaspectrometer in a north Indian patients as the available data is sparse. METHODS: Forty one patients who visited the dermatology outpatient department were recruited for this study. Skin type was grouped as per Fitzpatrick skin type scale. Patients' upper backs were irradiated after applying a novel template with 8 windows of 2 x 2 cm each, with a test dose ladder of 250-1500 mJ/cm2 in a Waldmann (700K) TL-01 chamber. MED and erythema index were read after 24 hours, the latter by using Dermaspectrometer. RESULTS: Forty one patients (10 males, 31 females) with mean age of 30.5 (14-65) years were recruited. 23 patients were of skin type 5, 17 of type 4 and one of skin type 3. The estimated MEDs were 1000 mJ/cm2 in 17, 750 mJ/cm2 in 19, 1100 mJ/cm2 in four and 500 mJ/cm2 in one patient. The median and mode MED was 1000 mJ/cm2. There was an exponential rise in the erythema index with increase in irradiation (17.18-26.25/250-1500 mJ/cm2). Student's t-test applied to detect differences between the visual and Dermaspectrometer readings was found to be statistically not significant. CONCLUSION: The estimated MED for NB-UVB varied from 500 to 1100 mJ/cm2, the median MED being 1000 mJ/cm2. The darker skin types did not have low MED while some patients with lighter skin type displayed lower MED. There was no significant difference in MED determined by visual and Dermaspectrometer readings.

Ultraviolet protective properties of branded and unbranded sunglasses available in the Indian market in UV phototherapy chambers.

BACKGROUND: Patients receiving phototherapy for various dermatoses are at increased risk of eye damage due to ultraviolet (UV) rays. They are prescribed UV protective sunglasses by dermatologists but their exact protecting effects are not known. AIM: To study the ultraviolet protective properties of branded and unbranded UV protective sunglasses available in the Indian market, in UV phototherapy chambers. METHODS: Sixteen different branded and unbranded UV protective sunglasses were collected from two opticians in Mumbai. Baseline irradiance of the UV chamber was calculated by exposing the photosensitive probe of UV photometer in the chamber. Then, the photosensitive probe of the UV photometer was covered with the UV protective glass to be studied and irradiance was noted. Such readings were taken for each of the UV protective sunglasses. The percentage reduction in the UV rays' penetration of different UV protective sunglasses was calculated. RESULTS: Thirteen sunglasses provided > 80% reduction in UVA rays penetration, of which four were branded (out of the four branded studied) and nine were unbranded (out of the 12 unbranded studied). More than 70% reduction in UVB penetration was provided by 12 sunglasses, which included 10 unbranded and two branded sunglasses. CONCLUSION: All branded sunglasses provided good protection against UVA penetration, but UVB protection provided by both branded and unbranded sunglasses was not satisfactory. A few unbranded sunglasses had poor efficacy for UVA and UVB spectra; one branded glass had poor efficacy for protection against the UVB spectrum. The efficacy of sunglasses used for phototherapy should be assessed before use.