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Background: Distinguishing weak allergic reactions from irritant patch test reactions may be difficult.Objectives: To describe the dermoscopic features of allergic reactions (especially weak allergic ones) and irritant patch test reactions, and to assess the suitability of dermoscopy in supporting differential diagnosis.Methods: Eligible participants for this observational, cross-sectional study included consecutive adult outpatients patch tested during a 12-month period, who developed any skin reaction. Healthy volunteers were patch tested with sodium lauryl sulfate as irritant controls. At the 72-hour reading, patch test reactions were recorded both with a digital camera and a digital dermoscopic system. For each reaction, clinical and dermoscopic variables were separately assessed, scored, and then compared.Results: Erythema, vessels, and vesiculation were constant dermoscopic features of allergic reactions (n = 173). In 46 weak (+) allergic reactions, dermoscopy showed (a) erythema (100%), (b) dense polymorphic vessels (100%), and (c) whitish vesicles (78.3%). Scores for vesicles and dotted vessels were significantly higher in weak allergic than in irritant reactions. Vesicles were identified as the chief dermoscopic parameter for correctly distinguishing weak allergic from irritant reactions.

<b><i>Background:</i></b> Some risk factors for malignant melanoma (MM) are recognized. <b><i>Objective:</i></b> To compare the strength of association between MM and eruptive cherry angiomas (CAs) with that of other well-known associations. <b><i>Methods:</i></b> This cross-sectional study included all subjects referred to the Outpatient Dermatology-Oncology and Dermoscopy Units of the Universities of Ferrara and Bologna, Italy, over a 5-month period and submitted to total body skin examination. We recorded: age, sex, cutaneous and non-cutaneous malignancies, presence of CAs, arbitrarily considered as “eruptive” when &#x3e;10, &#x3e;40 common melanocytic naevi or &#x3e;2 clinically atypical naevi. The strength of association between the possible risk factors and MM was calculated by odds ratio in both the whole population and age quartiles. Variables associated with MM were included in multiple logistic regression analysis. <b><i>Results:</i></b> 1,190 subjects were included; 615 had malignant skin tumours, 462 MM, 85 extracutaneous tumours. Five hundred and eighty-seven subjects had eruptive CAs, 485 subjects &#x3e;40 melanocytic naevi and 368 more than 2 atypical melanocytic naevi. Eruptive CAs, especially in subjects younger than 70, and &#x3e;2 atypical melanocytic naevi, mostly in subjects older than 50, were significantly associated with MM. The strength of these 2 associations was similar. The presence of &#x3e;40 melanocytic naevi was not associated with MM. <b><i>Conclusions:</i></b> These findings confirmed an association between MM and eruptive CAs, which was as strong as the one between MM and &#x3e;2 atypical melanocytic naevi. CAs seem an intriguing model of interaction between heterogeneous variables, like immunocompetence, stimuli inducing endothelial cell proliferation, and oncogenesis, which deserves further investigation.

The use of the internet to obtain medical information is becoming increasingly common among patients as a substitute for consulting a healthcare provider. 1 The present case is a typical example of sequelae of self-diagnosis and self-therapy in a patient who preferred to look for a "do-it-yourself" solution online. CASE REPORTA 32-year-old non-atopic male presented with intense pruritic erythematous dermatitis in his groins and scrotum ( Figure 1A) after selfadministration of various unspecified topical medicaments. The patient reported that he had searched for his symptoms, namely "burning and redness", on Google, and had come to the conclusion he was suffering from an infection. He therefore applied Benzac 5% gel, as suggested online, but the skin eruption worsened. Thereafter, he used PREP cream, which, according to online descriptions, had "calming properties", but there was no improvement. Finally, our treatment with systemic antihistaminic and topical corticosteroids and antibiotics along with cessation of other topical medicaments led to rapid resolution of the dermatitis. Patch testing was performed with the Italian Society of Allergological, Occupational and Environmental Dermatology (SIDAPA) baseline series (Lofarma, Milano, Italy) on Van der Bend chambers (Van derBend, Brielle, The Netherlands) and with both of the abovementioned topical products tested "as is". Patch tests were applied under occlusion on the patient's back for 2 days; readings were performed on day (D) 2 and D4 according to ESCD guidelines. 2 A positive reaction (++ on D4) was observed to the patient's own product, Benzac gel 5% ( Figure 1B). Further patch testing with benzoyl peroxide 2% pet. was performed, and yielded an extreme positive reaction (+++) on D4 ( Figure 1C). Allergic contact dermatitis caused by benzoyl peroxide was thus diagnosed. DISCUSSIONThe finding of allergic contact dermatitis induced by an anti-acne product applied to the genital area is quite unusual. The tendency to seek advice concerning health problems online is very widespread.More and more often, patients rely on information that they obtain on the web, which is, however, very often of little scientific value. 1,3 380CORAZZA ET AL.Prompted by this unusual case, we decided to go online to better understand the Italians' interest in the dermatological field. "GoogleTrends" 4 is a novel, freely accessible tool that allows users to interact with internet search data. It may provide insights into population behaviour and health-related phenomena. Google Trends is based on the Google search engine, and shows the frequency of searching for a specific word or topic on the web. Each search term is assigned a number between 0 and 100, which indicates the normalization of the search term's frequency, as compared with the total number of Google searches over time. 3 Line graphs show the relative search volume of each word, and bar graphs show the relative average search volume of each word. We carried out research on Google Trends to compare the trends of 3 common ch...

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