Potential role of reduced environmental UV exposure as a driver of the current epidemic of atopic dermatitis.

The basis for the sudden and dramatic increase in atopic dermatitis (AD) and related atopic diseases in the second half of the 20th century is unclear. The hygiene hypothesis proposes that the transition from rural to urban living leads to reduced childhood exposure to pathogenic microorganisms. Hence instead of having the normal TH1 bias and immune tolerance because of repeated exposure to pathogens, urban dwellers have TH2 cell immune activity and atopic disease in a more sterile environment. Various other environmental exposures have been implicated in the explosion of AD (and atopic disorders in general), including breast-feeding, tobacco smoking, alcohol consumption, and exposure to domesticated furry pets. Notably, the key role of a compromised barrier of neonatal skin as a predisposing factor in the development of childhood AD has recently been demonstrated. In this article we review the salubrious effects of suberythemogenic doses of UVB irradiation for the skin barrier. We then discuss how the lack of sufficient UVB exposure could have contributed to the rapid increase in the incidence of AD in developed countries. This hypothesis offers a separate but not competing partial explanation, which should be viewed as not discounting the role of the etiopathogenic factors that also could influence the prevalence of atopic disorders.

Granulomatous Rosacea and Periorificial Dermatitis: Controversies and Review of Management and Treatment.

Granulomatous rosacea and periorificial dermatitis are common skin conditions affecting the face. This article examines the historical origin, causes, clinical presentation, and management strategies for these entities.

Patch test reactions associated with sunscreen products and the importance of testing to an expanded series: retrospective analysis of North American Contact Dermatitis Group data, 2001 to 2010.

BACKGROUND: Both active and inactive ingredients in sunscreen may cause contact dermatitis. OBJECTIVES: This study aimed to describe allergens associated with a sunscreen source. METHODS: A cross-sectional analysis of patients patch tested by the North American Contact Dermatitis Group between 2001 and 2010 was performed. RESULTS: Of 23,908 patients patch tested, 219 (0.9%) had sunscreen coded as an allergen source. Patients who were male, with occupational dermatitis, or older (older than 40 years) had significantly lower rates of allergic reactions to sunscreens; the most commonly affected areas were the face and exposed sites (P < 0.0001). The top 3 most frequent allergens in sunscreens were benzophenone-3 (70.2% for 10% concentration, 64.4% for 3% concentration), DL-alpha-tocopherol (4.8%), and fragrance mix I (4.0%). Less than 40% of positive patch test reactions were detected by the North American Contact Dermatitis Group screening series of 65 to 70 allergens. CONCLUSIONS: A supplemental antigen series is important in detecting allergy to sunscreens.

North American Contact Dermatitis Group patch test results for 2007-2008.

BACKGROUND: The North American Contact Dermatitis Group (NACDG) tests patients with suspected allergic contact dermatitis to a broad series of screening allergens and publishes periodic reports. OBJECTIVE: The aims of this study were to report the NACDG patch-testing results from January 1, 2007, to December 31, 2008, and to compare results to pooled test data from the previous 2 and 10 years to analyze trends in allergen sensitivity. METHODS AND MATERIALS: Standardized patch testing with 65 allergens was used at 13 centers in North America. χ analysis was used for comparisons. RESULTS: A total of 5085 patients were tested; 11.8% (598) had an occupationally related skin condition, and 65.3% (3319) had at least 1 allergic patch test reaction, which is identical to the NACDG data from 2005 to 2006. The top 15 most frequently positive allergens were nickel sulfate (19.5%), Myroxylon pereirae (11.0%), neomycin (10.1%), fragrance mix I (9.4%), quaternium-15 (8.6%), cobalt chloride (8.4%), bacitracin (7.9%), formaldehyde (7.7%), methyldibromoglutaronitrile/phenoxyethanol (5.5%), p-phenylenediamine (5.3%), propolis (4.9%), carba mix (4.5%), potassium dichromate (4.1%), fragrance mix II (3.6%), and methylchloroisothiazolinone/methylisothiazolinone (3.6%). There were significant increases in positivity rates to nickel, methylchloroisothiazolinone/methylisothiazolinone, and benzophenone-3. During the same period of study, there were significant decreases in positivity rates to neomycin, fragrance mix I, formaldehyde, thiuram mix, cinnamic aldehyde, propylene glycol, epoxy resin, diazolidinyl urea, amidoamine, ethylenediamine, benzocaine, p-tert-butylphenol formaldehyde resin, dimethylol dimethyl hydantoin, cocamidopropyl betaine, glutaraldehyde, mercaptobenzothiazole, tosylamide formaldehyde resin, budesonide, disperse blue 106, mercapto mix, and chloroxylenol. Twenty-four percent (1221) had a relevant positive reaction to a non-NACDG supplementary allergen; and 180 of these reactions were occupationally relevant. CONCLUSIONS: Periodic analysis, surveillance, and publication of multicenter study data sets document trends in allergen reactivity incidence assessed in the patch test clinic setting and provide information on new allergens of relevance.

Systemic contact dermatitis.

Systemic contact dermatitis (SCD) describes a cutaneous eruption in response to systemic exposure to an allergen. The exact pathologic mechanism remains uncertain. The broad spectrum of presentations that are often nonspecific can make it difficult for the clinician to suspect this disease, but it is an important diagnosis to consider in cases of recalcitrant, widespread, or recurrent dermatitis, in which patch testing often reveals allergy to nickel or balsam of Peru. Diagnosis and appropriate management can be life-altering for affected patients. This article on SCD provides an overview of the disease with descriptions of common allergens and some insight into the possible mechanism of action seen in SCD.