Allergic Contact Dermatitis Caused by White Petrolatum on Damaged Skin

Christine C. Tam; Dirk M. Elston

Disclosures

Dermatitis. 2006;17(4):201-203. 

In This Article

Discussion

Petrolatum (CnH2n+2) is a mixture of semisolid hydrocarbons. There are four main types of petrolatum: natural, artificial, gatsch, and synthetic. Natural petrolatum is obtained from the purification of petroleum to remove odors and modify the color. White and yellow petrolatums are both natural petrolatums. The purification process is extended further in white petrolatum than in yellow petrolatum, so that practically all of the former's yellow color is removed. Artificial petrolatum is a mixture of natural hydrocarbon waxes and refined paraffin oils. Gatsch petrolatum is derived from mixing the by-products of petroleum distillates with paraffin oil. Finally, synthetic petrolatum is made from synthetic hydrocarbons obtained by carbon monoxide hydrogenation.[1,2,10]

The allergens present in petrolatum have been found to most likely be polycyclic aromatic hydrocarbons. These are impurities whose quantities vary depending on the source of the petroleum and the purification procedures performed.[11] Thus, there is often marked variation in allergenicity between brands of petrolatum produced by different manufacturers. Because of the extension of its purification process, white petrolatum contains fewer sensitizing contaminants than yellow petrolatum contains.[12] White petrolatum has become the primary petrolatum used today.[9]

Past reports of sensitivity reactions to petrolatum include a case of immediate and long-lasting urticaria and dermatitis due to petrolatum,[3] a case of chronic dermatitis and hyperpigmentation caused by yellow and white petrolatum,[4] and several cases of allergic contact dermatitis caused by yellow and white petrolatum.[1,2,5,6,7,8,9] On general patch testing, patients in these cases reacted to many allergens that were dispersed in the petrolatum. Petrolatum allergies were then confirmed by specific patch tests.[1,2,5,6,7,8,9] In one case report, the patient reacted to one batch but not to another batch of the same brand of petrolatum; the authors concluded that the amount of sensitizing contaminants not only varies between brands but may also vary between different batches of the same brand of petrolatum.[9]

In one particular study involving three patients with leg ulcers, Dooms-Goossens and Degreef discovered that the patients reacted to petrolatums on their leg ulcers despite having negative patch-test reactions to the same petrolatums on intact skin. The authors concluded that even if a petrolatum does not elicit a reaction on healthy skin, it may cause an eczematous reaction on damaged skin.[12]

Like the leg ulcer patients in the aforementioned study, our patient had a positive reaction to petrolatum only on damaged skin. He had negative patch-test results for the whole battery of allergens applied to healthy back skin, including the many allergens dispersed in white petrolatum. Only patch testing with white petrolatum on scratched skin yielded a positive delayed hypersensitivity reaction.

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