Inger Dahlquist

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.

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.

Allergic contact dermatitis from acrylates in ultraviolet curing inks.

Six patients developed dermatitis while working with ultraviolet curing inks in four different printing plants. Contact allergy was found to the multifunctional acrylate monomers pentaerythritol triacrylate (PETA) and trimethylol propane triacrylate (TMPTA) and to the epoxy acrylate and polyesteracrylate prepolymers.

Release of nickel from plated utensils in permanent wave liquids

Soluble cutting oil dermatitis is generally of an irritant type. An allergic type of contact dermatitis occurs but is rare. The allergens are additives such as preservatives and anti-rust agents or nickel, cobalt or chromate which have contaminated the fluid. Recently, one case of cutting oil dermatitis with colophony (rosin) allergy was seen. A man aged 50 had worked as a turner for many years. He had developed hand dermatitis 1 year before our examination. The dermatitis had relapsed several times after sick leave periods. After the last sick-leave period, he had used potassium soap water instead of cutting oil. Within 2 days the hand dermatitis relapsed more severely than before. Patch testing with the ICDRG series (Altest®, Imeco-Astra) showed a positive reaction to colophony. The cutting oil used for the last 2 years contained 10 % soap (as emulsifier) made of tall oil fatty acids and triethanolamine. The fatty acids contained 25 % colophony. The cutting oil was diluted with water to 5 %. The potassium soap was made from tall oil fatty acids, which contained 20 % colophony, mainly consisting of abietic acid and isomers. Patch testing with the tall oil (25 % in olive oil), tall fatty acids with 2 % colophony (50 % in olive oil), tall rosin (10 % in MEK), abietic acid (10 % in MEK) and soap (2 % in water) all gave positive reactions. These substances have been tested in seven other patients with colophony sensitivity. Reaction to all the compounds was positive. It is obvious that the patient had been sensitized to colophony in the cutting oil and that the severe relapse was caused by the colophony in the soap water. Owing to the high frequency of dermatitis from cutting oils in the metal industry, employees in Sweden at present demand that cutting oils should be replaced by soap water. There is a potential risk of allergic contact dermatitis from the soap because of the presence of colophony. At present cutting fluid based on vegetable oil soaps is under technical and dermatological investigation.

A simple method for the detection of formaldehyde.

The commonly used chromotropic acid method for the determination of formaldehyde sometimes produces a masking discolouration. We have therefore evaluated a complementary method in which acetylacetone is used as the reagent. By a combination of the 2 methods, formaldehyde can be traced in most products.

Contact allergy to trimethylolpropane triacrylate (TMPTA) in an aziridine plastic hardener

4 workers developed hand and face dermatitis when exposed to a floor top coal. This contained a polyurethane arid a polyfunctional aziridine hardener and additives. The aziridine hardener was made by reacting propyleneimine with a polyfunctional acrylate, trimethylolpropane triacrylate (TMPTA). All 4 reacted to the hardener and to TMPTA, which is present in excess, 2 of them also reacted to pentacrythritol triacrylate (PETA), which can be used in the production of aziridine hardeners. TMPTA and PETA cross‐react, and are known sensitizers in UV‐hardening acrylates.

Allergic contact dermatitis from volatile epoxy hardeners and reactive diluents

A 22-year-old hairdresser developed eczema localized to the back of the second and third fingers of her right hand. She was patch tested (Leukotest, Beiersdorf) with the European Standard and hairdressing tray (Trolle-Lassen), and with several products she handled in her job. At 72 h there was a + + reaction to nickel. She told us that when doing permanent waving, she held clips with the first three fingers of her right hand in such a way that permanent wave liquid drained between the second and third fingers where eczema lesions were seen. Irritant contact dermatitis by permanent wave liquid could be a possibility. However, with a little modification of the dimethylglyoxime (DMG) stick test (Shore & Binnick 1977), we could show release of nickel from the clips by the permanent wave liquid. A cotton tipped applicator was dipped in permanent wave liquid and rubbed against the clip. Then a few drops of DMG 1 % in alcohol were added and a characteristic rose color appeared in the cotton tip. Recently, Dahlquist et a!. (1979) demonstrated by means of atomic absorption spectrophotometry that nickel was released in considerable amounts when nickel-plated utensils were soaked in permanent wave liquids. With a simpler method, we could prove that our patients eczema was almost certainly nickel related.

Reliability of the chromotropic acid method for qualitative formaldehyde determination

Some questions. Probably there is contact sensitivity but is the dermatitis allergic eczematous; it looks more irritant, remains localized and does not vesiculate, thus lacking two of the cardinal signs of AECD. What is a correct patch test concentration? I find that more than 10 % is often irritant. What is the sensitizer? It seems to be water and ethanol soluble. Is it allyldisulphide which produces positive patch test reactions in some patients at 5 % pet.? Is it alliin or allicin or a breakdown product difficult to isolate? A major problem is patch testing in a suitable concentration with substances which are highly irritant and also labile. For practical management of such patients I do not patch test with garlic. A voidance of garlic is recommended but often does not seem to help this particular type of desiccated dermatitis. Nearly all of the culinary vegetables used by the homemaker have been reported to cause contact dermatitis in an industrial setting of large exposure (Mitchell & Rook 1978). Yet we rarely patch test for vegetable dermatitis in housewifes eczema. Significant screening and aimed test sets, appropriately standardized in nonirritant concentration and suitably preserved, are needed for vegetable AECD together with scratch/prick test sets for vegetable contact urticaria. The last has also been reported for Allium and is suspect in some of our cases.

Detection of formaldehyde in corticoid creams

In a previous report it was shown that the chromotropic acid method for determination of formaldehyde could give false negative results by discoloration (Dahlquist et a!. 1980). Therefore a fluorimetric method was used (Wilson 1974). This method had to be modified as we analyzed creams and not solutions. Formaldehyde was extracted from the specimens with 10 % methanol in water under magnetic stirring for 1 h. The extract was incubated with the reagent at 60° C for 1 h. The sample was filtered through a Millipor® teflon filter (0.22 f!m). (Some Millipor cellulose filters contained formaldehyde.) After measurement of the emission, the samples were examined by scanning from 400 to 700 nm to check that the maximum emission was at 510 nm. The detection limit was 5 f!g formaldehyde/g. Cosmetics, topical medicaments, dish washing liquids and shampoos giving discoloration with the chromotropic acid method were analyzed with the fluorimetric method. About half of the samples giving discoloration contained formaldehyde, confirming that the chromotropic acid method can give false negative results. Out of 20 corticoid creams, 16 gave positive reactions with the chromotropic acid method, but none gave discoloration. Analyzed with the fluorimetric method, these creams were found to contain up to 51 f!g formaldehyde/g. In seven corticoid ointments no formaldehyde amount above the detection limit was found. When the constituents of the creams were analyzed, formaldehyde was found in polyethylene glycols (carbowaxes, macrogol) and in derivatives of these. It is known that autoxidation of polyethylene glycols and derivatives gives formaldehyde among other compounds, and that heat increases the degradation (Rieger 1975, Hamburger et a!. 1975). Sterilization of corticoid creams and ointments is prescribed by Swedish law. The preparations are commonly heated at 140° C for 3 h. To investigate the formation of formaldehyde, polyethylene glycols and some derivatives were heated at 140° C for 3 h. Formaldehyde was determined by the qualitative chromotropic acid method. Several polyethylene glycols that had been stored in the laboratory contained formaldehyde. Only those free from formaldehyde were heated. Carbowax 400, 1500, 3000 and 4000 contained formaldehyde after heating. The derivatives Tween 60® (polyoxyethylene sorbitan monostearate) and Cetomacrogol (Texofor AlP, polyethylene glycol monocetylether) also formed formaldehyde during the heating procedure. When emulsions are made they are often heated at about 70° C. The Carbowax 3000 was heated at 70° C for 30 min and then contained formaldehyde. The amounts of formaldehyde found are probably not high enough to induce sensitization, but may maintain dermatitis in previously formaldehyde-sensitized subjects. The formaldehyde in the samples analyzed is, however, a contaminant, so the amount may vary between batches.

Sensitization capacity of diphenylthiourea and phenylisothiocyanate.

patch test results is shown in Table 2. There is no stastically significant difference in the frequency of positive reactions between females and males (p>0.05.) As regards the interpretation of test reactions, it should be noted that some might have been misjudged. This is especially so for potassium dicyanoaurate. Most of these reactions should probably be considered as irritant and to some extent this is also valid for the reactions marked +, as for potassium bichromate and cobol! chloride. Experiences with this preliminary test series have shown modifications to be appropriate. A suggestion for a revised series has now been published (I).