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result(s) for
"Irritants"
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Controlled comparison evaluation of the soothing effect of 3 cosmetic products on skin discomfort induced by an irritant chemical agent (capsaicin)
2024
Background Sensitive skin is a highly prevalent problem. The objective of the study was to assess whether the tested products are effective and safe in terms of improving the symptoms of sensitive skin. Methods A clinical randomized split‐face study was carried out on 24 healthy female subjects. Three cosmetic combinations were tested versus vehicle: product A (Solía Thermal Spring Water–TSW–from Cantabria, Spain + diatom algae–P. tricornutum–extract), product B (Solía TSW + diatom algae extract + Annona cherimola Fruit Extract) and product C (Solía TSW + diatom algae extract + Annona cherimola Fruit Extract + niacinamide). Prior to each application of the study Product (A, B, or C)/vehicle, 10% of aqueous solution of capsaicin to induce skin irritation was applied, mimicking the symptoms of sensitive skin. Stinging and burning sensations were evaluated at different time points. Results All three tested products A, B, and C showed to act better in calming the symptoms induced by capsaicin when compared to the vehicle. Conclusions The tested products would be an interesting option for treating stinging and burning sensations in sensitive skin patients.
Journal Article
Machine-learning–driven biomarker discovery for the discrimination between allergic and irritant contact dermatitis
2020
Contact dermatitis tremendously impacts the quality of life of suffering patients. Currently, diagnostic regimes rely on allergy testing, exposure specification, and follow-up visits; however, distinguishing the clinical phenotype of irritant and allergic contact dermatitis remains challenging. Employing integrative transcriptomic analysis and machine-learning approaches, we aimed to decipher disease-related signature genes to find suitable sets of biomarkers. A total of 89 positive patch-test reaction biopsies against four contact allergens and two irritants were analyzed via microarray. Coexpression network analysis and Random Forest classification were used to discover potential biomarkers and selected biomarker models were validated in an independent patient group. Differential gene-expression analysis identified major gene-expression changes depending on the stimulus. Random Forest classification identified CD47, BATF, FASLG, RGS16, SYNPO, SELE, PTPN7, WARS, PRC1, EXO1, RRM2, PBK, RAD54L, KIFC1, SPC25, PKMYT, HISTH1A, TPX2, DLGAP5, TPX2, CH25H, and IL37 as potential biomarkers to distinguish allergic and irritant contact dermatitis in human skin. Validation experiments and prediction performances on external testing datasets demonstrated potential applicability of the identified biomarker models in the clinic. Capitalizing on this knowledge, novel diagnostic tools can be developed to guide clinical diagnosis of contact allergies.
Journal Article
Itch and Pain Behaviors in Irritant Contact Dermatitis Produced by Sodium Lauryl Sulfate in Mice
by
Zhang, Zhe
,
LaMotte, Robert H.
,
Shimada, Steven G.
in
Animals
,
Behavior
,
Behavior, Animal - drug effects
2024
Irritant contact dermatitis (ICD) is a nonspecific skin inflammation caused by irritants, leading to itch and pain. We tested whether differential responses to histamine-dependent and -independent pruritogens can be evoked in ICD induced by sodium lauryl sulfate (SLS). An ICD mouse model was established with 5% SLS in acetone versus a vehicle topically applied for 24 h to the cheek. Site-directed itch- and pain-like behaviors, occurring spontaneously and in response to mechanical, thermal, and chemical stimuli (histamine, ß-alanine, BAM8-22, and bradykinin) applied to the cheek, were recorded before (day 0) and after irritant removal (days 1, 2, 3, and 4). Skin inflammation was assessed through visual scoring, ultrasound, and measurements of skin thickness. SLS-treated mice exhibited hyperalgesia-like behavior in response to mechanical and heat stimuli on day 1 compared to the controls. SLS mice exhibited more spontaneous wipes (pain) but not scratching bouts (itch) on day 1. Pruritogen injections caused more scratching but not wiping in SLS-treated mice compared to the controls. Only bradykinin increased wiping behavior compared to saline. SLS-treated mice developed noticeable erythema, scaling, and increased skin thickness on days 1 and 2. SLS induced cutaneous inflammation and behavioral signs of spontaneous pain and itching, hyperalgesia to mechanical and heat stimuli and a chemical algogen, and enhanced itch response to pruritogens. These sensory reactions preceded the inflammation peak and lasted up to two days.
Journal Article
Sensory irritation as a basis for setting occupational exposure limits
by
Pallapies, Dirk
,
Stropp, Gisela
,
Gundert-Remy, Ursula
in
Air Pollutants, Occupational - chemistry
,
Air Pollutants, Occupational - pharmacokinetics
,
Air Pollutants, Occupational - toxicity
2014
There is a need of guidance on how local irritancy data should be incorporated into risk assessment procedures, particularly with respect to the derivation of occupational exposure limits (OELs). Therefore, a board of experts from German committees in charge of the derivation of OELs discussed the major challenges of this particular end point for regulatory toxicology. As a result, this overview deals with the question of integrating results of local toxicity at the eyes and the upper respiratory tract (URT). Part 1 describes the morphology and physiology of the relevant target sites, i.e., the outer eye, nasal cavity, and larynx/pharynx in humans. Special emphasis is placed on sensory innervation, species differences between humans and rodents, and possible effects of obnoxious odor in humans. Based on this physiological basis, Part 2 describes a conceptual model for the causation of adverse health effects at these targets that is composed of two pathways. The first, “sensory irritation” pathway is initiated by the interaction of local irritants with receptors of the nervous system (e.g., trigeminal nerve endings) and a downstream cascade of reflexes and defense mechanisms (e.g., eyeblinks, coughing). While the first stages of this pathway are thought to be completely reversible, high or prolonged exposure can lead to neurogenic inflammation and subsequently tissue damage. The second, “tissue irritation” pathway starts with the interaction of the local irritant with the epithelial cell layers of the eyes and the URT. Adaptive changes are the first response on that pathway followed by inflammation and irreversible damages. Regardless of these initial steps, at high concentrations and prolonged exposures, the two pathways converge to the adverse effect of morphologically and biochemically ascertainable changes. Experimental exposure studies with human volunteers provide the empirical basis for effects along the sensory irritation pathway and thus, “sensory NOAEC
human
” can be derived. In contrast, inhalation studies with rodents investigate the second pathway that yields an “irritative NOAEC
animal
.” Usually the data for both pathways is not available and extrapolation across species is necessary. Part 3 comprises an empirical approach for the derivation of a default factor for interspecies differences. Therefore, from those substances under discussion in German scientific and regulatory bodies, 19 substances were identified known to be human irritants with available human and animal data. The evaluation started with three substances: ethyl acrylate, formaldehyde, and methyl methacrylate. For these substances, appropriate chronic animal and a controlled human exposure studies were available. The comparison of the sensory NOAEC
human
with the irritative NOAEC
animal
(chronic) resulted in an interspecies extrapolation factor (iEF) of 3 for extrapolating animal data concerning local sensory irritating effects. The adequacy of this iEF was confirmed by its application to additional substances with lower data density (acetaldehyde, ammonia,
n
-butyl acetate, hydrogen sulfide, and 2-ethylhexanol). Thus, extrapolating from animal studies, an iEF of 3 should be applied for local sensory irritants without reliable human data, unless individual data argue for a substance-specific approach.
Journal Article
The Unique Molecular Signatures of Contact Dermatitis and Implications for Treatment
2019
Irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD) are common skin disorders that are characterized by inflammation, oozing, crusting, and pruritus. Atopic dermatitis (AD) is an inflammatory skin disease characterized by immune and barrier abnormalities and is additionally a risk factor for acquiring ICD and ACD. New work on allergic sensitization to common allergens (e.g., nickel and fragrance) in human skin has shown that different allergens have distinct molecular fingerprinting. For example, nickel promotes strong Th1/Th17 polarization, whereas fragrance allergy causes Th2/Th22 skewing, which is similar to the phenotype of AD. While ACD has previously been considered to be constant across all allergens, largely based on mouse models involving strong sensitizers, these new data suggest that ACD differs mechanistically according to allergen. Further, ACD in the setting of concurrent AD shows a different and attenuated phenotype as compared to healthy individuals with ACD, which influences the way AD patients respond to vaccination and other treatment modalities. As in contact sensitization, skin challenged by food patch testing shows that common food allergens (e.g., peanut and barley) also cause distinct immune polarizations in the skin. Additionally, house dust mite reactions in human skin have been profiled to show unique Th2, Th9, and Th17/22 activation as compared to controls, which are similar to the phenotype of psoriasis and contact responses to nickel. Given this information, ACD patients should be treated based on their unique allergen polarity. Refined understanding of the molecular behavior of contact dermatitis and related diseases translates to improved methods of inducing tolerance in sensitized allergic patients, such as with targeted drug therapy and epicutaneous immunotherapy.
Journal Article
Direct comparison of laser Doppler flowmetry and laser Doppler imaging for assessment of experimentally-induced inflammation in human skin
2013
Objective and design
Laser Doppler imaging (LDI) and laser Doppler flowmetry (LDF) can measure localized skin perfusion. The purpose of the study was to directly compare LDF with LDI as a tool for measuring skin blood changes in an experimental model of chemically-induced skin inflammation.
Methods
Regions of interest 1.8 cm
2
in area on the forearm skin of eight healthy volunteers were randomized and exposed to 0.25, 0.5, 1, or 2 % topical sodium lauryl sulfate (SLS) or vehicle for 24 h. Mean blood flow was measured by LDI and LDF at 24, 48, and 72 h. Inflammation was clinically graded using a standardized, clinical score.
Results
Sodium lauryl sulfate induced significant, dose-dependent local inflammation. Both Doppler methods were significantly correlated with the clinical grading (LDF,
r
= 0.755; LDI,
r
= 0.836). LDF and LDI showed similar significance differences with regard to dose- and time-response patterns compared to the vehicle. The absolute and relative LDF and LDI values were significantly correlated.
Conclusions
Laser Doppler flowmetry and LDI showed similar dose- and time-response relations in irritant-induced inflammatory skin reactions. For the assessment of localized skin reactions, LDI possesses no apparent advantages over the less expensive LDF method for grading dermal inflammatory reactions.
Journal Article
Tracking and quantification of dendritic cell migration and antigen trafficking between the skin and lymph nodes
2014
Skin-derived dendritic cells (DCs) play a crucial role in the maintenance of immune homeostasis due to their role in antigen trafficking from the skin to the draining lymph nodes (dLNs). To quantify the spatiotemporal regulation of skin-derived DCs
in vivo
, we generated knock-in mice expressing the photoconvertible fluorescent protein KikGR. By exposing the skin or dLN of these mice to violet light, we were able to label and track the migration and turnover of endogenous skin-derived DCs. Langerhans cells and CD103
+
DCs, including Langerin
+
CD103
+
dermal DCs (DDCs), remained in the dLN for 4–4.5 days after migration from the skin, while CD103
−
DDCs persisted for only two days. Application of a skin irritant (chemical stress) induced a transient >10-fold increase in CD103
−
DDC migration from the skin to the dLN. Tape stripping (mechanical injury) induced a long-lasting four-fold increase in CD103
−
DDC migration to the dLN and accelerated the trafficking of exogenous protein antigens by these cells. Both stresses increased the turnover of CD103
−
DDCs within the dLN, causing these cells to die within one day of arrival. Therefore, CD103
−
DDCs act as sentinels against skin invasion that respond with increased cellular migration and antigen trafficking from the skin to the dLNs.
Journal Article
Improvement of sulphur mustard-induced chronic pruritus, quality of life and antioxidant status by curcumin: results of a randomised, double-blind, placebo-controlled trial
2012
Skin is among the first and most heavily damaged organs upon sulphur mustard (SM) exposure. Pruritus is the most common chronic skin complication of SM, which adversely affects the quality of life (QoL). However, current therapies for the management of SM-induced pruritus are very limited and associated with side effects. The present trial investigated the efficacy of curcumin in the alleviation of SM-induced chronic pruritic symptoms. A total of ninety-six male Iranian veterans (age 37–59 years) were randomised to receive either curcumin (1 g/d, n 46) or placebo (n 50) for 4 weeks. Serum concentrations of substance P and activities of antioxidant enzymes were measured at baseline and at the end of the trial. Assessment of pruritus severity was performed using the pruritus score, visual analogue scale (VAS) and scoring atopic dermatitis (SCORAD) index. QoL was evaluated using the Dermatology Life Quality Index (DLQI) questionnaire. Serum concentrations of substance P (P < 0·001) as well as activities of superoxide dismutase (P = 0·02), glutathione peroxidase (P = 0·006) and catalase (P < 0·001) were significantly reduced in the curcumin group, while no significant change was observed in the placebo group. Curcumin supplementation was also associated with significant reductions in measures of pruritus severity including the pruritus score (P < 0·001), VAS score (P < 0·001), overall (P < 0·001) and objective SCORAD (P = 0·009), and DLQI's first question (P < 0·001). None of these measures was significantly changed in the placebo group. As for the QoL, although DLQI scores decreased in both groups (P < 0·001 and P = 0·003 in the curcumin and placebo groups, respectively), the magnitude of reduction was significantly greater in the curcumin group (P < 0·001). In conclusion, curcumin may be regarded as a natural, safe, widely available and inexpensive treatment for the management of SM-induced chronic pruritus.
Journal Article
Atopic Dermatitis: Identification and Management of Complicating Factors
by
Katoh, Norito
,
Tamagawa-Mineoka, Risa
in
Aerosols
,
Allergens - classification
,
Allergens - immunology
2020
Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease, associated with impaired skin barrier function and an atopic background. Various complicating factors, such as irritants, aeroallergens, food, microbial organisms, contact allergens, sweat, and scratching can induce the development of AD symptoms. Irritants, including soap/shampoo and clothes, can cause itching and eczematous lesions. In addition, young children with AD tend to become sensitized to eggs, milk, or peanuts, while older children and adults more often become sensitized to environmental allergens, such as house dust mites (HDM), animal dander, or pollen. Serum-specific IgE levels and skin prick test reactions to food tend to show high negative predictive values and low specificity and positive predictive values for diagnosing food allergy. On the other hand, AD adult patients tend to have severe skin symptoms and exhibit high HDM-specific IgE levels. Microbial organisms, e.g., Staphylococcus aureus and Malassezia furfur, might contribute to the pathogenetic mechanisms of AD. While sweat plays a major role in maintaining skin homeostasis, it can become an aggravating factor in patients with AD. Furthermore, scratching often exacerbates eczematous lesions. Several patient-specific complicating factors are seen in most cases. The identification and management of complicating factors are important for controlling AD.
Journal Article
Occupational hazards in agriculture – a severe case of lime sulphur-induced irritant contact dermatitis with characteristic skin manifestations
by
Xu, Yang
,
Liu, Yu
,
Zheng, Huijing
in
Calcium Compounds - adverse effects
,
Calcium Compounds - toxicity
,
Contact dermatitis
2025
A 58-year-old female patient presented with erythema, swelling, erosions, yellow-white crusts, and severe pain in both hands for one day. Distinct from typical cases of allergic contact dermatitis, the condition progressed rapidly, characterized by leather-like crusts resembling adhered lime and scattered erosions. After one month of treatment, the lesions resolved almost completely, leaving residual scars and mild functional impairment. This case report describes occupational exposure to lime sulphur, a strongly alkaline pesticide known to cause severe irritant contact dermatitis, and emphasizes the importance of proper handling procedures, enhanced protective measures, and systematic clinical management following exposure.
Journal Article