Dathan Hamann

Bio: Dathan Hamann is an academic researcher from Ohio State University. The author has contributed to research in topics: Allergic contact dermatitis & Medicine. The author has an hindex of 15, co-authored 42 publications receiving 639 citations. Previous affiliations of Dathan Hamann include Phoenix Contact & University of Arizona.

Association between atopic dermatitis and contact sensitization: A systematic review and meta-analysis

Abstract: Background It is unclear whether patients with atopic dermatitis (AD) have an altered prevalence or risk for contact sensitization. Increased exposure to chemicals in topical products together with impaired skin barrier function suggest a higher risk, whereas the immune profile suggests a lower risk. Objective To perform a systematic review and meta-analysis of the association between AD and contact sensitization. Methods The PubMed/Medline, Embase, and Cochrane databases were searched for articles that reported on contact sensitization in individuals with and without AD. Results The literature search yielded 10,083 citations; 417 were selected based on title and abstract screening and 74 met inclusion criteria. In a pooled analysis, no significant difference in contact sensitization between AD and controls was evident (random effects model odds ratio [OR] = 0.891; 95% confidence interval [CI] = 0.771-1.03). There was a positive correlation in studies that compared AD patients with individuals from the general population (OR 1.50, 95% CI 1.23-1.93) but an inverse association when comparing with referred populations (OR 0.753, 95% CI 0.63-0.90). Limitations Included studies used different tools to diagnose AD and did not always provide information on current or past disease. Patch test allergens varied between studies. Conclusion No overall relationship between AD and contact sensitization was found. We recommend that clinicians consider patch testing AD patients when allergic contact dermatitis is suspected.

Spectrometric analysis of mercury content in 549 skin-lightening products: is mercury toxicity a hidden global health hazard?

Abstract: Background Cosmetic skin lightening is practiced worldwide. Mercury is a well-documented melanotoxin added to some lightening products. However, mercury can cause many dermatologic, renal, and neurologic problems. The Food and Drug Administration limits the amount of mercury in cosmetic products to trace amounts, 1 ppm. Objective The objective of this study was to quantitatively evaluate a large international sample of lightening products for mercury content, focusing on products available to US consumers either online or in stores. Methods A total of 549 skin-lightening products, manufactured in 32 countries, were purchased online in the United States, Taiwan, and Japan and in stores in the United States, China, Taiwan, Thailand, Japan, and Sri Lanka. Cosmetics were screened for mercury content above 200 ppm using a low-cost portable x-ray fluorescence spectrometer. Results Of the 549 tested products, 6.0% (n = 33) contained mercury above 1000 ppm. In all, 45% of mercury-containing samples contained mercury in excess of 10,000 ppm. Of lightening products purchased in the United States, 3.3% were found to contain mercury in excess of 1000 ppm. Limitations Our study did not evaluate creams for other melanosuppressive ingredients. Only 1 sample of each product was tested. Conclusion Our study confirms the national and global presence of mercury in skin-lightening products.

p‐Phenylenediamine and other allergens in hair dye products in the United States: a consumer exposure study

Abstract: Summary Background Hair dye products constitute an important source of allergen exposure, and contribute importantly to allergic contact dermatitis in consumers and hairdressers. Objectives To evaluate the presence of potent contact sensitizers in oxidative hair dye products intended for home use on the US market. Methods Ingredient labels of 107 hair dyes from 10 major brands were examined and used to assess the prevalence of hair dye substances known to be potent contact sensitizers. Results One hundred and six of 107 (99%) products contained at least one potent sensitizer, and the average product contained six (range 0–11). p-Phenylenediamine (PPD) was found in 83 products (78%), but resorcinol (89%), m-aminophenol (75%), p-aminophenol (60%) and toluene-2,5-diamine (21%) were also frequently identified. Conclusions Potent contact sensitizers were almost universally included in the hair dyes investigated in the United States. Although PPD is a common allergen, resorcinol and m-aminophenol were found more frequently. In total, 30 potent sensitizers were found. Clinicians should consider other allergens in addition to PPD when evaluating patients with suspected hair dye allergy.

Epidemic of Isothiazolinone Allergy in North America: Prevalence Data From the North American Contact Dermatitis Group, 2013-2014.

Abstract: BACKGROUND Preservative sensitivity patterns evolve with changing use patterns in products During the last decade, the use of methylisothiazolinone (MI) at higher concentrations in both leave-on and rinse-off products has significantly increased This is the first North American Contact Dermatitis Group reporting cycle that includes both methylchloroisothiazolinone (MCI)/MI and MI data OBJECTIVE The aim of this study was to report the prevalence of isothiazolinone allergy (MCI/MI and MI) in the North American Contact Dermatitis Group patch-test population from January 1, 2013, to December 31, 2014 METHODS At 13 centers in North America, 4860 patients were patch tested in a standardized manner with a series of 70 allergens, including MCI/MI 001% aqueous (aq) and MI 02% aq RESULTS Three hundred five patients (63%) had a positive reaction to MCI/MI; this is a significant increase from the previous cycle (50%, 2011-2012; P = 0011) Five hundred twenty-one patients (107%) had a positive reaction to MI These 2 isothiazolinones were among the most common preservative allergens in the 2013 to 2014 cycle; 119% of patch-tested individuals were allergic to 1 or both isothiazolinones Individuals with MCI/MI and MI allergy were significantly more likely to have occupationally related skin disease (P < 00001) and hand dermatitis (P < 00001, P = 00474) CONCLUSIONS The epidemic of isothiazolinone sensitivity documented in Europe is now in North America Patch testing with only MCI/MI 001% aq will miss approximately half of isothiazolinone allergy cases, whereas testing with only MI 02% aq will miss approximately 10% of isothiazolinone allergy cases

Assessment of nickel release from earrings randomly purchased in China and Thailand using the dimethylglyoxime test.

Abstract: Background: China and Thailand produce large amounts of jewellery that are sold domestically and abroad. Objective: To identify nickel release and metal content in earrings purchased in China and Thailand. Methods: A total of 557 earrings were randomly purchased from vendors in 11 markets located in Beijing, Chengdu, Bangkok, Patong Beach, and Hat Yai. Earrings were subjected to dimethylglyoxime (DMG) tests and 26 of the DMG negative earrings were further evaluated qualitatively for major and minor metal content using X-ray fluorescence spectrometry. Results: A total of 314 Chinese earrings (31.5%) and 243 Thai earrings (29.2%) were DMG test positive. Three (11.5%) of 29 DMG negative earrings contained nickel as a major component; 7 (26.9%) of 29 DMG negative earrings contained nickel as a minor component. Discussion: Excessive nickel release was frequent. This may contribute to the high prevalence of nickel allergy in both countries. Increased public education together with the adoption of a regulatory intervention in Thailand may be warranted. In China, enforcement of the 2002 Chinese National Standard GB 11887 may assist in reducing sensitization. These initiatives may eventually result in decreased morbidity among the Chinese and Thai citizens, but can potentially benefit recipient countries of these important earring producing countries.

Environmental Mercury and Its Toxic Effects

Abstract: Mercury exists naturally and as a man-made contaminant. The release of processed mercury can lead to a progressive increase in the amount of atmospheric mercury, which enters the atmospheric-soil-water distribution cycles where it can remain in circulation for years. Mercury poisoning is the result of exposure to mercury or mercury compounds resulting in various toxic effects depend on its chemical form and route of exposure. The major route of human exposure to methylmercury (MeHg) is largely through eating contaminated fish, seafood, and wildlife which have been exposed to mercury through ingestion of contaminated lower organisms. MeHg toxicity is associated with nervous system damage in adults and impaired neurological development in infants and children. Ingested mercury may undergo bioaccumulation leading to progressive increases in body burdens. This review addresses the systemic pathophysiology of individual organ systems associated with mercury poisoning. Mercury has profound cellular, cardiovascular, hematological, pulmonary, renal, immunological, neurological, endocrine, reproductive, and embryonic toxicological effects.

Cycling of mercury in the environment: Sources, fate, and human health implications: A review

Abstract: Mercury (Hg) is ubiquitary, naturally enriched in volcanic regions, and has wide applications in science, industry, and agriculture Recently, the increasing awareness of Hg toxicity has led to the replacement of Hg in many areas; however, anthropogenic activities such as coal burning and smelting of metal ores continue to release large amounts of Hg into the environment In particular, the atmospheric distribution of the highly volatile Hg around the globe can result in the pollution of pristine regions without local emission sources The chemical speciation of Hg determines its mobility and toxicity; in flooded soils and sediments, microbial methylation can occur Bioaccumulative (mono)methylmercury (MeHg; CH3Hg+) can affect human health particularly via the consumption of contaminated fish and rice since methylmercury is a potent neurotoxin Also, elemental Hg vapor is harmful for the central nervous system, while inorganic Hg compounds primarily affect the kidney This review summarizes recent