Perianal North American blastomycosis.

Cutaneous North American blastomycosis most often results from the hematogenous spread of Blastomyces dermatitidis following pulmonary infection. Cutaneous lesions, which may be either verrucous or ulcerative plaques, commonly occur on or around orifices contiguous to the respiratory tract. We report the case of a 57-year-old man with cutaneous North American blastomycosis who presented with a well-demarcated, firm, moist, verrucous perianal plaque 4 months following the onset of a prolonged upper respiratory tract infection. Dissemination of B dermatitidis to the perianal skin is rare, but North American blastomycosis should be considered in the broad differential diagnosis of perianal lesions in any patients who have lived in or traveled to endemic regions.

Positivity ratio and reaction index: patch-test quality-control metrics applied to the north american contact dermatitis group database.

BACKGROUND: The positivity ratio (PR) and reaction index (RI) characterize the ability of patch-test preparations to produce strong (++ or +++) reactions as opposed to weak (+), questionable, or irritant reactions. OBJECTIVE: This study evaluates these measures for North American Contact Dermatitis Group (NACDG) patch-test preparations. METHODS: The PR and RI were calculated for 79 NACDG standard allergens tested from 1994 to 2006 (n = 26,479 patients). The median values were used as cutoff values for "acceptable" versus "problematic" preparations. RESULTS: The top 10 "acceptable" patch-test preparations (PR < or = 55 and RI > 0.46) were mixed dialkyl thioureas 1% in petrolatum (pet), tixocortol-21-pivalate 1% pet, ethylenediamine dihydrochloride 1% pet, sesquiterpene lactone mix 0.1% pet, nickel sulfate 2.5% pet, bacitracin 20% pet, thimerosal 0.1% pet, epoxy resin 1% pet, colophony 20% pet, and mercaptobenzothiazole 1% pet. The most "problematic" patch-test preparations (PR > 55 and RI < or = 0.46) were cocamidopropyl betaine 1% aqueous (aq), benzalkonium chloride 0.1% aq, jasmine absolute 2% pet, iodopropynyl butyl carbamate 0.1% pet, 2-bromo-2-nitropropane-1,3-diol 0.5% pet, methyldibromoglutaronitrile 0.4% pet, methyldibromoglutaronitrile/phenoxyethanol 2% pet and 2.5% pet, dimethylol dihydroxyethyleneurea 4.5% aq, and clobetasol-17-propionate 1% pet. CONCLUSION: Caution should be used when interpreting reactions to "problematic" patch-test preparations with a high proportion of weak, irritant, and questionable reactions.

Positive patch test reactions to lanolin: cross-sectional data from the north american contact dermatitis group, 1994 to 2006.

BACKGROUND: The prevalence of lanolin sensitivity in referred patients is less than 4%. OBJECTIVES: To (1) describe patients with positive patch-test reactions to lanolin, (2) determine clinical and occupational relevance associated with reactions to lanolin and common sources, and (3) examine the frequency of co-reacting allergens. METHODS: A retrospective analysis of 26,479 patients patch-tested by the North American Contact Dermatitis Group (NACDG), 1994 to 2006. RESULTS: Overall, 2.5% of patients (643 of 25,811) tested to lanolin alcohol 30% in petrolatum had positive reactions. Prevalence decreased from 3.7% in 1996 to 1998 to 1.8% in 2005 to 2006 (p <.0001); 83.4% of all positive reactions were currently relevant, but only 2.5% were occupationally relevant. Lanolin-positive patients were 1.2 times more likely to be male and 1.4 times more likely to have a history of atopic dermatitis when compared to allergic, but lanolin-negative, patients (p < .0002 and p < .0001, respectively). Cosmetics were the most common source. Lanolin-positive patients were significantly more likely to be co-sensitized to another NACDG standard screening allergen (p <.0001). CONCLUSIONS: The prevalence of allergic patch-test reactions to lanolin in North America patch-test populations is decreasing. Current relevance of reactions was high, but occupational relevance was low. Concomitant reactions were more common in lanolin-positive patients.