Johansen, JD; Jemec, GBE; Rastogi, SC
Dipropylene glycol (DG) has been considered safe to use as a solvent in perfumes and other cosmetics (1). Our recent case of allergic contact dermatitis from DG in a hand lotion (2) prompted this further study.
Materials and Methods: We used standard (S) DG (synthesis grade purity >97%) from E. Merck (Darmstadt, Germany) and cosmetic grade (CG) DG (purity 96%) from our case (2). In a pilot study, 34 eczema patients were patch tested with either S or CG DG at 10%, 5%, 2% and 1% aq. When no reactions were seen, the standard series at Gentofte was supplemented with DG 10% aq., S and CG, for 7 months (25.1.94- 25.8.94). 503 consecutive eczema patients, 212 men and 291 women, were tested, patches being applied for 2 days, using Scanpor tape and Finn Chambers, and reactions being read at D2, D3 and 05-7. The original patient (2) was repatch tested with both S and CG DG at I% and 0.5% aq.
Results: 6. 7% (34/503) of the patients reacted to at least 1 of S and CG DG (Table 1). There was l positive patch test reaction to S DG, the remaining reactions being either ?+, 5.1% (26/503), or IR, 1.4% (7/503) (no sex difference). 10 of those with ?+ reactions to DG were also tested with their own cosmetics and 2 reacted, l to mascara, skin tonic and eye shadow, and I to camomile liniment (DG contents not determined). The original patient (2) had + + and + + + reactions to CG DG, as well as to S DG, 0.5% and 1% aq.
Discussion: DG is a mixture of 3 isomers (1), their distribution in the 2 grades used in this study differing as determined by GC/MS (2). The original patient (2) reacted to both grades and no difference was found between the frequency of reactions to the 2 grades in 503 consecutive eczema patients. Only 1 patient out of 503 (0.2%), however, had a definitely positive patch test reaction to DG, its clinical relevance not being established. Patch testing with other grades of DG used in cosmetics (I) might give different results, but at present, we consider contact allergy to dipropylene glycol to be rare in our study population.
