Sensitization to isothiazolinones in the Spanish Contact Dermatitis Registry (REIDAC): 2019-2021 epidemiological situation.

BACKGROUND: Current frequency and risk factors for sensitization to methylisothiazolinone (MI), methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), benzisothiazolinone (BIT) and octylisothiazolinone (OIT) in Spain are not well known. OBJECTIVES: To study the frequency of sensitization, risk factors and simultaneous sensitization between the four isothiazolinones. MATERIALS AND METHODS: We analysed all 2019-2021 consecutive patients patch-tested with MI (0.2% aq.), MCI/MI (0.02% aq.), BIT (0.1% pet.) and OIT (0.1% pet) within the Spanish Contact Dermatitis Registry (REIDAC). RESULTS: A total of 2511 patients were analysed. Frequencies of sensitization were: any isothiazolinone 15.7%, MI 6.8%, MCI/MI 4.8%, BIT 3.5% and OIT 0.5%. MI and MCI/MI sensitization was associated with being occupationally active, hand dermatitis, detergents and age over 40. BIT sensitization was associated with leg dermatitis and age over 40. About one in nine MI-positive patients were positive to BIT, whereas one in five BIT-positive patients were positive to MI. CONCLUSIONS: Sensitization to MI, MCI/MI and BIT is still common in Spain, while sensitization to OIT is rare. Currently, sensitization to MI and MCI/MI seems to be occupationally related. Although its origin is unknown, sensitization to BIT is more frequent in patients aged over 40 years. Simultaneous sensitization between MI and BIT is uncommon.

Silicone Granulomas at the Peripheral Intravenous Cannula Puncture Site.

ABSTRACT: Different adverse reactions to silicone present in cosmetic fillers, implants, or medical devices have been reported. The granulomatous reaction on the injection site due to catheters' silicone coating is an infrequent complication, which may be clinically difficult to suspect. Although the definitive diagnosis requires identification of the silicone with techniques such as X-ray spectroscopy, the possibility of involvement of silicone, as well as the histopathologic demonstration of granulomas with refractile, nonpolarizable, and nonstainable material strongly suggests this diagnosis. Moreover, the use of a low-diaphragm aperture or phase-contrast microscopy could be useful to demonstrate the presence of this, otherwise almost transparent, foreign body.

Scabies in a 14-year-old girl with superficial epidermolytic ichthyosis.

A 14-year-old girl who reported generalized scaling and hyperkeratosis since age 1 year presented with severe pruritus of several months' duration. Scabies mites were detected, and molecular genetic analysis subsequently revealed a rare pathogenic variant in the keratin 2 (KRT2) gene, confirming a diagnosis of superficial epidermolytic ichthyosis. Treatment with oral ivermectin led to complete remission of symptoms. Disorders of keratinization can mimic clinical signs of scabies, leading to a delay in diagnosis.

Should methyldibromo glutaronitrile continue to be used in the European baseline Series? A REIDAC national cross-sectional study.

BACKGROUND: Methyldibromo glutaronitrile (MDBGN) was one of the most frequent and relevant allergens found in patch testing at the beginning of this century. In 2008, this preservative was banned from cosmetics in Europe and ever since the prevalence of contact allergy to MDBGN has progressively decreased. Despite that gradual decline, MDBGN is still patch-tested in most baseline series. This study assessed the frequency of MDBGN sensitization, epidemiological characteristics of allergic patients, and the relevance of positive patch tests in a nationwide Spanish registry (REIDAC). PATIENTS AND METHODS: We evaluated consecutively patch-tested patients in all participating centres. Using these data, we calculated the proportion of patients with positive patch tests to MDBGN from June 2018 to June 2020 and evaluated the relevance of the positive patch tests. RESULTS: One hundred and fourteen out of 5072 (2.24 %) tested patients were sensitized to MDBGN. Clinical current relevance was confirmed in only one case. CONCLUSION: Although the frequency of contact allergy to MDBGN remains high, no clinical significance was found in most of these patients (5072 tests needed to obtain one relevant positive result). The clinical usefulness of this allergen seems weak and its continued inclusion in the European baseline series is questionable.

Sweet's syndrome triggered by ultraviolet light.

Sweet's syndrome is a neutrophilic dermatosis associated with many different underlying conditions but only rarely is it triggered by environmental factors such as ultraviolet (UV) exposure. We present two cases of photoinduced Sweet syndrome. Our first patient, who was taking hydrochlorothiazide, presented photodistributed lesions, pathological phototest and neutrophilic dermatosis histopathology. The phototest normalized after drug withdrawal, suggesting that both UV light and hydrochlorothiazide were necessary to cause the lesions. Our second case presented lesions clearly induced by UV light and histologically consistent with Sweet's syndrome. The MED was decreased and the lesions were reproduced with nbUVB, suggesting the diagnosis of photoinduced Sweet's syndrome. In conclusion, we report a case of neutrophilic dermatosis induced by hydrochlorothiazide and UV light and a case of photoinduced Sweet's syndrome with reproduction of the lesions after nbUVB. Both patients had a pathologic photobiological study. Our report emphasizes the need to perform phototests in patients with photodistributed Sweet's syndrome.