Birgitta Gruvberger

Contact allergy to the preservative Kathon® CG

Of 976 patients routinely patch tested with Kathon® CG (Rohm & Haas), 300 ppm. 43 (4.4%) gave a positive reaction. Of 170 patients routinely tested with Kathon® CG 250 ppm, 10 (5.9%) gave a positive reaction. Out of 34 patients tested with serial dilution of Kathon® CG, 17 (50%) reacted to to 100 ppm, 8 to 30 ppm and 2 to 10 ppm. The concentration of 1000 ppm of Rathon® CG was irritant in some cases, but 300 ppm was not irritant.

Recommendation of appropriate amounts of petrolatum preparation to be applied at patch testing.

Background:  No recommendation exists on the amount of petrolatum (pet.) preparation to be applied in a Finn Chamber® or van der Bend Chamber.

Reduction of chromate in cement by iron sulfate.

Cement dermatitis is connected with chromate sensitivity. It can therefore be expected that “elimination” of chromate in cement would decrease the number of cases of cement dermatitis.

Occupational contact allergy and dermatitis from methylisothiazolinone after contact with wallcovering glue and after a chemical burn from a biocide.

Skin exposure to biocides containing high concentrations of methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) may cause severe chemical burns and may also induce sensitization. We report two cases in which skin exposure to a newly launched biocide containing 2-methyl-4-isothiazolin-3-one (MI) and 1,2-benzisothiazolin-3-one led to sensitization to Ml, which in the second case was preceded by a chemical burn. A study was performed to investigate the pattern of reactivity to MCI and Ml in two patients who presumably had a primary sensitization to Ml and in one patient who had been sensitized to MCI/MI by being patch-tested. The patients were patch-tested with serial dilutions of MCI/MI, MCI, MI, and 2-n-octyl-4-isothiazolin-3-one. The first two patients reacted to both MCI/MI and the separate active ingredients, with a higher level of reactivity to Ml than to MCI. The third patient reacted to MCI/MI and MCI only. A biocide containing Ml caused sensitization and occupational contact dermatitis in the first two patients, through contact with wallpaper glue in one case and after a chemical burn in the other case.

Contact allergy to the active ingredients of Kathon® CG

The preservative Kathon1 CG is a commercial preparation, consisting of 2 active ingredients and other components. 28 patients with contact allergy to Kathon CG participated in a study in which patch testing was performed with serial dilutions, and with 5 chromatographically separated fractions. All reacted to fraction IV, and 2 patients also to fraction II. Mass spectrometry and nuclear magnetic resonance spectrometry identified fraction II and IV lo be the active ingredients; 2‐melhyl‐4‐isothia‐zolin‐3‐one and 5‐chloro‐2‐methyl‐4‐isothiazolin‐3‐one.

Sensitization studies in the guinea pig with the active ingredients of Euxyl K 400.

The preservative Euxyl® K 400 consists of the 2 active ingredients, 2‐phenoxyethanol and 1, 2‐dibromo‐2, 4‐dicyanobutane. Sensitization studies with the guinea pig maximization test were performed with these substances, but no sensitizing capacity was demonstrated in the case of either compound.

Linalool - a significant contact sensitizer after air exposure

Background: Linalool is a widely used fragrance terpene. Pure linalool is not allergenic or a very weak allergen, but autoxidizes on air exposure and the oxidation products can cause contact allergy. Oxidized (ox.) linalool has previously been patch tested at a concentration of 2.0% in petrolatum (pet.) in 1511 patients, and 1.3% positive patch test reactions were observed.

Preservatives in moisturizers on the swedish market

The presence of 9 common preservatives was investigated in 100 moisturizers by high-performance liquid chromatography. According to the manufacturers/suppliers 88 of the 100 moisturizers contained at least one of the 9 preservatives. This information was erroneous in 9 cases (10.2%). When the moisturizers were investigated for the presence of the 9 preservatives which should not be present in the moisturizers according to the manufacturers/suppliers, at least one of the preservatives was detected in 17 moisturizers (17.0%). Parabens were the most common preservatives. The concentrations of the 9 preservatives did not exceed the maximum concentrations allowed in cosmetics. When a patient with suspected allergic contact dermatitis tests positively to a preservative, the assessment of present clinical relevance requires demonstration of exposure to the sensitizer. This demonstration cannot rely solely on information on the packages or from the manufacturers/suppliers but has often to be supplemented by chemical analysis.

Recommendation to include methyldibromo glutaronitrile in the European standard patch test series

The preservative methyldibromo glutaronitrilc (MDBGN) is used non‐occupationally and occupationally. High contact allergy rates have been reported when tested in consecutive dermatitis patients as well as clinical cases with allergic contact dermatitis. Up till now there has been no agreement on which patch test preparation to use to trace contact allergy to MDBGN. From the year 2005 on, MDBGN at 0.5% w/w in petrolatum is recommended for the European standard patch test series. The choice of 0.5% is based on consideration of rates of contact allergy, doubtful and irritant reactions, as well as on information on clinical relevance represented by results of a repeated open application test, and patch test concentrations to diagnose allergic contact dermatitis from MDBGN in individual cases.

A correlation found between contact allergy to stent material and restenosis of the coronary arteries

Background:  Metallic implants, stents, are increasingly being used especially in patients with stenosis of the cardiac vessels. Ten to thirty per cent of the patients suffer from restenosis regardless of aetiology. We have shown increased frequency of contact allergy to stent metals in stented patients.