Allergic contact dermatitis: Effect of age
Department of Dermatology, School of Medicine, University of California-San Francisco, CA, USA.Cutaneous and Ocular Toxicology (Impact Factor: 1.12). 07/2011; 31(1):20-5. DOI: 10.3109/15569527.2011.595749
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.
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ABSTRACT: The objective of this study was to identify an adjuvant for anesthetics coated on microneedles to provide rapid onset and prolonged analgesic action with minimal skin tissue reaction. Aqueous lidocaine or prilocaine formulations with or without clonidine or the related analogs, guanfacine and apraclonidine, were dip-coated onto polymeric microneedles. The amount of lidocaine or prilocaine coated onto the microneedles was assessed by high performance liquid chromatography (HPLC). Delivery efficiency and dermal pharmacokinetics associated with lidocaine or prilocaine delivered via the microneedles were characterized in vivo using domestic swine. Skin punch biopsies were collected and analyzed to determine the anesthetic concentrations in the skin using HPLC-mass spectrometry (LC-MS). Addition of clonidine to the formulations decreased the systemic absorption rate of the anesthetics from the patch application site without impacting the coating performance or the rapid onset of anesthesia. Formulations with 0.3wt.% clonidine, identified as the optimal dose for lidocaine-delivery via microneedles, maintained the lidocaine skin concentration above the estimated therapeutic level (100ng/mg) for 1h without causing any skin irritation or color change. The other two clonidine analogs, guanfacine and apraclonidine, also led to delayed systemic absorption of lidocaine from the skin, indicating utility in providing prolonged analgesia.International Journal of Pharmaceutics 09/2012; 439(1-2). DOI:10.1016/j.ijpharm.2012.09.041 · 3.65 Impact Factor
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ABSTRACT: Background. Two readings of patch test reactions are recommended. Objectives. To evaluate the outcome of a second patch test reading of TRUE Test® allergens on D6/7 in relation to negative or doubtful reactions on D3/4. Methods. This was a retrospective investigation of patch test data from January 1992 to October 2011 from consecutive eczema patients tested with the TRUE Test® panels. Results. In the period of nearly 20 years, a total of 9997 patients were tested. The total number of positive reactions to the 29 allergens was 6509; 4.4% were positive on D6/7 and negative on D3/4; and 9.1% were positive on D6/7 after a doubtful (?+) reaction on D3/4. Neomycin was the most frequent allergen giving delayed positive reactions (57%), followed by budesonide (42%) and hydrocortisone-17-butyrate (31%). Conclusion. A total of 4.4% of positive TRUE Test® reactions would be missed, and 9.1% might be missed, if only one reading was performed on D3/4. The results emphasize that many doubtful reactions at D3/4 may develop into positive reactions at a later reading. This may have important implications for evaluation of the clinical relevance of the test result.Contact Dermatitis 02/2013; 68(2):94-7. DOI:10.1111/cod.12004 · 3.75 Impact Factor
- Contact Dermatitis 07/2013; 69(1):53-5. DOI:10.1111/cod.12093 · 3.75 Impact Factor
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