Methyldibromoglutaronitrile is an important contact allergen in The Netherlands

From 15 May to 15 December 1994, 2943 patients sunspected of having contact dermatitis(1955 women, 988 men) were patch tested with methyldibromoglutarorutrile 0.3%, 0.1% and 0.05% pet. 119 patients (4.0%: women 4.1%, men 3.8%) proved to be allergic, 71% of the reactions were considered to be relevant. In 2/3 of the patients, causative products were cosmetics, in 1/3 moistened toilet tissues. Testing with methyldibromoghitaronitrile at lower concentrations (0.05% and 0.1%) commercial allergens (Euxyl® K 400 and methyldibromoglutaronitrile, both containing methyldibromoglutaronitrile 0.1%). resulted in a number of falsc‐negative reactions. All preservatives in the European standard series had lower scores than the 4% positive reactions to methyldibromoglutaronitrile (formaldehyde 2.0% MCI/MI (Kathon® CG) 3.2% parabens 1.0% quaternium‐15 1.3%). It is concluded that methyldibromoglutaronitrile (present in the commercial preservative Euxyl® K 400) is an important contact allergen in the Netherlands in cosmetics and moistened toilet tissues. It should be added to cosmetics series and to proctological series. The optimal test concentration is unknown, but may be 0.3% pet. The concentration of 0.1% methyldibromoglutaronitrile in the currenttly available commercial allergens appears to be too low. resulting in a number of false‐negative reactions.