Allergic contact dermatitis: effect of age

The relationship between allergic contact dermatitis (ACD) and age has not been well documented. We searched for articles and textbooks based on age–ACD relationship and evaluated relevant data. The frequency of skin reactions to allergens increased with age in some studies, whereas others showed no definite effect. This might be caused by variations in study design, genetic factors or by external influences such as from different regions and environmental exposure. In general, investigators agree that elderly patients were more likely to have multiple contact allergies than younger persons. This may be because of the frequent use of topical medicaments and having a longer time for potential allergen exposure. However, a review of marketed transdermal products for ACD shows a very low incidence, and no age-related effects were reported. One exception to this low incidence of ACD is the transdermal product, Catapres-TTS^® (clonidine), which has a reported incidence rate of ~16%. The generally low incidence of ACD in marketed products and the conflicting findings in the prevalence of specific age-related ACD indicate the need for further investigation as to the proclivity for developing new sensitivities with age.     

Allergic contact dermatitis: effect of age

The relationship between allergic contact dermatitis (ACD) and age has not been well documented. We searched for articles and textbooks based on age-ACD relationship and evaluated relevant data. The frequency of skin reactions to allergens increased with age in some studies, whereas others showed no definite effect. This might be caused by variations in study design, genetic factors or by external influences such as from different regions and environmental exposure. In general, investigators agree that elderly patients were more likely to have multiple contact allergies than younger persons. This may be because of the frequent use of topical medicaments and having a longer time for potential allergen exposure. However, a review of marketed transdermal products for ACD shows a very low incidence, and no age-related effects were reported. One exception to this low incidence of ACD is the transdermal product, Catapres-TTS(?) (clonidine), which has a reported incidence rate of ~16%. The generally low incidence of ACD in marketed products and the conflicting findings in the prevalence of specific age-related ACD indicate the need for further investigation as to the proclivity for developing new sensitivities with age.     

Irritant contact dermatitis in humans from phorbol and related esters

Nine compounds, based on four biogenetically-related polycyclic diterpene skeletons, were subjected to open and closed patch testing on human volunteer subjects. The tigliane esters phorbol-12, 13, 20-triacetate, 12-O-2Z-4E-octadienoyl-4-deoxyphorbol-13-acetate and 12-O-tigloyl-4-deoxyphorbol-13-isobutyrate, in increasing order of potency, produced symptoms of toxicity in closed patch tests, with the dose of the most potent compound in this series being 0.5 μg in 5 μl acetone. Phorbol, a tigliane alcohol, was inactive in closed tests at a dose level of 50 μg/5 μl. The daphnane derivative, daphnetoxin, produced bullae and vesiculation in closed patch tests, but daphnetoxin-5,20-diacetate was devoid of these effects when applied at 10 times the dose of daphnetoxin. The ingenane compounds, ingenol-3,5,20-triacetate and 20-deoxy-16-hydroxyingenol-3,5,16-triacetate, and the lathyrane compound, ingol-3,7,8,12-tetraacetate, were obtained from the hydrolyzed, acetylated irritant latex of Euphorbia hermentiana. At the doses tested, ingenol-3,5,20-triacetate was the only compound derived from this plant to exhibit irritant activity in closed patch tests. In contrast, this compound is inactive as an irritant to the mouse ear at doses up to 250 μg/ear. Only three compounds, 12-O-2Z-4E-octadienoyl-4-deoxyphorbol-13-acetate, 12-O-tigloyl-4-deoxyphorbol-13-isobutyrate and daphnetoxin, produced dermatological toxicity in open patch tests at the doses used. Inflammatory signs and symptoms for several of the compounds under test persisted for over four days in open patch tests and for a week or more after application in closed patch testing.     

Irritant nail dermatitis of chemical depilatory product presenting with koilonychia

Chemical hair removal products are available as creams, gels, powders, aerosols and roll-ons and all of these forms work in the same way by breaking chemical bonds between sulfur atoms in the protein. Currently, the common active ingredients of these products are calcium thioglycolate, potassium thioglycolate, arsenic and sulfur minerals. Sulfur and arsenic containing products are important toxic chemicals which are mainly used for removing hair in developing countries. Irritant contact dermatitis accounts for 80% of all contact dermatitis reactions which are often occupation-related. Toluene sulfonamide, formaldehyde resin, acrylates and ethylcyanoacrylate are the most common irritants. Irritant nail dermatitis with plants has been well defined with Lobelia richardii flower, Compositae family and garlic. Although allergic dermatitis, irritant dermatitis and irritant nail dermatitis have been well demonstrated with chemicals, koilonychia is unusual presentation of irritant dermatitis. Here we describe a case of nail irritant dermatitis due to application of chemical depilatory product for hair removal presented with koilonychias. To our knowledge this is the first case of such presentation with koilonychia in the English literature.     

青蒿琥酯对变应性接触性皮炎的免疫调节作用及其机制探讨

青蒿琥酯(AST)的免疫调节效应已被认可,但其具体作用的机制尚不明确。本研究通过变应性接触性皮炎(ACD)小鼠模型,初步探讨AST对ACD的免疫调节作用及可能的分子机制。采用药效学分析以及HE染色、半定量RT-PCR、Western blotting等方法分别检测AST对ACD相关细胞因子、转录因子及信号分子表达的影响。结果显示,局部应用AST能够抑制ACD小鼠耳肿胀度、脾指数、炎症细胞浸润以及IFN-γ、T-bet的表达,同时减弱NF-κB p65的表达。结果表明,AST能够通过抑制炎症反应和ACD小鼠免疫功能,调节机体的Th1/Th2失衡发挥作用,NF-κB可能是其作用靶点之一。     

Allergic contact dermatitis.

Allergic contact dermatitis (ACD) is a common occupational and environmental health issue. In common with other forms of allergy the disease progresses in two stages; an initial phase during which sensitization is acquired, followed later (after subsequent exposure to the same chemical allergen) by elicitation of a cutaneous inflammatory reaction. The development of skin sensitization is associated with, and requires, the activation and clonal expansion of allergen responsive T lymphocytes and it is these cells that orchestrate the cutaneous allergic reaction. In recent years, much has been learned of the characteristics of immune responses to skin sensitizing chemicals and of the roles played by dendritic cells, cytokines and chemokines. Some of the more interesting cellular and molecular mechanisms are reviewed briefly in this article. A more detailed appreciation of responses induced by chemical allergens has in turn facilitated the design of novel approaches to the toxicological evaluation of skin sensitization. Real progress has been made, not only in the development of improved methods for hazard identification and characterization, but also in the application of new paradigms for risk assessment. The newer methods now available and the opportunities that exist for further advances are considered. Finally, progress has been made in the characterization of skin sensitization in humans and in the clinical management of ACD. This article seeks to consider skin sensitization and ACD in holistic fashion, bridging experimental observations with clinical disease and basic mechanisms with practical toxicology.     

北沙参致接触过敏性皮炎

患者女,45岁。2003年始种植北沙参,在采收期间,接触北沙参0.5h后,自感双手出现剧烈瘙痒及烧灼感,继而出现皮肤红斑、水疱,经当地医生予以抗过敏药物口服治疗后痊愈。2004年夏季,当患者再次采收北沙参时,双手出现与前次同样感觉和皮疹,而且症状及体征均较去年明显加重,并有少量渗液及结痂。短期应用前次药物疗效不明显,于当年7月来我院皮肤科就诊,无明显家族过敏史。查体:系统检查无异常。皮肤症状:两手掌明显肿胀,轻度发红,有绿豆大小的水泡;两手背及前臂曲侧皮肤弥漫性水肿性红斑,边界清楚,红斑上密集分布针尖大小的丘疹和水疱,表面有少量…     

Autosensitization dermatitis associated with propolis-induced allergic contact dermatitis

Propolis is a beehive product known for its anti-inflammatory properties. With its growing use, propolis-induced contact dermatitis is increasing. While the dermatitis mostly occurs on areas directly exposed to propolis, our case presented an additional eczema at a site distant from the primary propolis-induced contact dermatitis twice in the same individual. We diagnosed it as an autosensitization dermatitis associated with propolis-induced allergic contact dermatitis.     

Pharmacotherapy for allergic contact dermatitis

Allergic contact dermatitis is a highly prevalent, potentially chronic disease, with a significant economic and quality of life impact. Culprit causal allergen(s) can be identified though patch testing, the ‘gold-standard’ diagnostic method. For most people, identification and subsequent avoidance of their clinically relevant allergens will results in resolution of the dermatitis. However, when an avoidance regimen is not possible, or an allergen is not identified, patients potentially require symptomatic and immunosuppressive therapy to diminish the manifestations of their disease. This article reviews a therapeutic approach to allergic contact dermatitis.     

Pharmacotherapy for allergic contact dermatitis

Allergic contact dermatitis is a highly prevalent, potentially chronic disease, with a significant economic and quality of life impact. Culprit causal allergen(s) can be identified though patch testing, the 'gold-standard' diagnostic method. For most people, identification and subsequent avoidance of their clinically relevant allergens will results in resolution of the dermatitis. However, when an avoidance regimen is not possible, or an allergen is not identified, patients potentially require symptomatic and immunosuppressive therapy to diminish the manifestations of their disease. This article reviews a therapeutic approach to allergic contact dermatitis.     

Allergic contact dermatitis to propolis

A 35-year-old Asian woman was referred to the dermatology clinic with a 2-week history of enlarging, fluid-filled, pruritic lesions on the right foot. The affected area had a recent history of minor trauma for which the patient applied an over-the-counter propolis ointment. At presentation, the patient was also noted to have been using the following, as prescribed by her primary care physician: valacyclovir, ciprofloxacin, terbinafine cream, mupirocin ointment, and 2% hydrocortisone cream. No clinical improvement was observed with these agents. Examination revealed grouped erythematous papules progressing into vesicles and bulla on the lateral side of the right foot. A KOH scraping was negative. We diagnosed the patient with allergic contact dermatitis to propolis.     

Systemic contact dermatitis to doxepin

Although allergic contact dermatitis to topical preparations of doxepin has been published, systemic contact dermatitis from oral doxepin is more of a theoretical consideration and is rarely reported. We report a case of a patient with contact allergy to doxepin hydrochloride 5% cream who developed a systemic contact dermatitis to oral doxepin.     

Allergic contact dermatitis from ophthalmics

In this article we summarize the recently described allergens responsible for allergic contact dermatitis due to ophthalmic drugs and contact lens solutions, and emphaage the need on how to perform diagnostic testing in this special clinical entity.     

Contact sensitisation and allergic contact dermatitis: immunobiological mechanisms

The dose-response relationships of the human immune system can be defined using the induction and elicitation of lymphocyte mediated allergic reactions to experimental contact sensitisers such as dinitrochlorobenzene (DNCB). Five groups of healthy volunteers received a sensitising dose of DNCB applied to a 3 cm diameter circle on the volar forearm. Doses applied were 62.5 microg, 125 microg, 250 microg, 500 microg and 1,000 microg. Four weeks later a concentration series of 3.125 microg, 6.25 microg, 12.5 microg and 25 microg was applied to the upper inner arm on 1cm paper discs which were removed after 6h. Forty-eight hours later the responses were scored clinically and thickness measured with callipers. The proportion of people reacting to the challenge doses showed a sigmoid log-dose-response curve, 100% reacting to 500 microg. The responses to challenge also showed a log-dose-reponse. As sensitising dose increased so more people were sensitised to a proportionately greater degree. These dose-response relationships reflect the effects of increasing the concentration of sensitiser on a fixed area. The effect was examined of keeping the concentration per sq cm constant but of varying the total area. When 35.4 microg/cm(2), which sensitised 80% of people when applied to a circle 3 cm diameter (area 7.1cm(2)), was applied on a 1.5 cm diameter circle or 4.5 cm diameter, there were no differences in the proportions sensitised or their degree of reactivity. This was clearly on the plateau for the sensitising effect. However, when the same concentration per cm(2) was applied on a 3mm diameter area much weaker sensitisation was obtained. This shows the concentration of sensitiser per unit area is the critical determinant of whether sensitisation occurs, whereas the total dose may be varied over a wide range, but if the concentration per unit area is constant there is no effect on sensitising potency. In other words few Langerhans cells presenting many antigen molecules per cell is a much more potent sensitising stimulus than the same number of molecules presented by many Langerhans cells, each presenting few molecules. These observations clearly have important implications across the whole field of risk assessment for induction of contact sensitivity.     

Allergic contact dermatitis caused by farnesol: clinical relevance

Context: The fragrance material farnesol is cited as an infrequent but important cause of allergic contact dermatitis (ACD). It is included in the fragrance mix II patch series and requires labeling in the European Union if it is used in a consumer product.

Objective: To review the existing literature to determine the causative role of farnesol in clinical contact allergy.

Materials and methods: Survey of the literature on farnesol studies; predictive and clinical elicitation tests in case reports, reviews, and abstracts.

Results: Predictive animal studies demonstrated in most cases that farnesol was a nonsensitizer. However, 2 local lymph node assays (LLNAs) indicated strong sensitization potential. Predictive human test data indicated a low potential, if any, for sensitization in human tests with farnesol at 10% or 12%. A few clinical reports indicated low-level allergy or questionable reactions to farnesol, with 5% being the most commonly used. There were also reports in which no reactions were seen.

Discussion: Predictive testing on farnesol in animals shows conflicting results depending on the study methodology used. Human predictive patch-test data also had gaps that prevented it from being definitive in pointing to a causative relationship between farnesol and contact dermatitis. The real sensitizing potential of a material can best be determined by evaluating the clinical and epidemiological data so as to help resolve the conflicting animal and human predictive test data.

Conclusions: This literature and scoring exercise showed that predictive and clinical elicitation data do not document a clear causative determination that farnesol is a frequent contact allergen. Detailed clinical relevance and patient studies should clarify the clinical problem farnesol represents.     

Therapeutic strategies in allergic contact dermatitis

Due to its high prevalence, allergic contact dermatitis (ACD) has an important economic and occupational health impact on society. ACD presents as an inflammatory response to small molecules and involves both skin resident cells and activated skin infiltrating T cells. Activation of skin resident cells plays an essential role in the initial sensitization phase. A number of different pathways are crucially involved in this phase including the activation of pattern recognition receptors such as TLR, inflammasome activation and production of reactive oxygen species all of which contribute to release of cellular mediators such as IL-1 family members. Chemokines regulate steps in elicitation of adaptive T cell responses including the migration to and presentation of the contact allergen by skin derived antigen presenting cells in the draining lymph node as well as the recruitment of these activated, allergen reactive CD4+ and CD8+ cells back into the skin. The current therapeutic regimens are largely restricted to the avoidance of the contact allergen and the topical use of anti-inflammatory drugs such as glucocorticosteroids. Recent research, as highlighted by current patents, focus on the use of anti-oxidants, the induction of immunological tolerance, interference with cell signaling molecules and blocking of cytokines actively involved in ACD.     

Epidermal cytokines in experimental contact dermatitis

Topical exposure to a variety of xenobiotics may result in irritant as well as allergic contact dermatitis both in rodents and in humans. Despite their induction by different mechanisms, they cannot be differentiated by macroscopic appearance and, by histological examination they are both generally characterized by a perivascular mononuclear cell infiltrate and capillary hyperpermeability. Recently, cytokines, a family of inducible glycoproteins that play a pivotal role in immune and inflammatory reactions, have been identified as useful tools for differentiation of irritant and allergic contact dermatitis. In this article the role of cytokines in the development and differentiation of irritant and allergic contact dermatitis is discussed.     

Structure-activity relationships in allergic contact dermatitis

Skin sensitization by simple chemicals involves reaction with nucleophilic groups on skin proteins or possibly on proteins in cell membranes to form haptenic groups, which act as allergenic determinants. A quantitative model for sensitization by 'alkylating agents', the RAI (Relative Alkylation Index) theory, has been devised and applied to the sensitization observed with three model series of compounds--p-nitrobenzyl halides and saturated and unsaturated sultones. Examination of chemical structures, and predictions of the types of chemical reaction that substances may undergo, can be used to assess the likely reactivity of unknown materials towards skin proteins. In addition such examinations of structure may be used to assess the likely cross-reactivity of materials. The pro-hapten concept of Dupuis & Benezra (Allergic Contact Dermatitis to Simple Chemicals. A Molecular Approach. Marcel Dekker, New York) offers an explanation for the sensitization potential of substances that do not contain chemically reactive groups prior to in vivo conversion and for cross-reactions between apparently unrelated chemicals.