Ampliative medicament allergy: concomitant sensitivity to multiple medicaments including yellow soft paraffin, white soft paraffin, gentian violet and Span 20

White petrolatum (Ph. Eur.) is virtually non-sensitizing. Analysis of IVDK data on 80 000 patients tested between 1992 and 2004 and short discussion of identification and designation of allergens

Sporadic cases of contact allergy to white petrolatum, which is used as a vehicle in patch test preparations, have been reported. The quantitative relevance of the phenomenon remains yet to be elucidated.

METHODS

Retrospective analysis of patch test data of the Information Network of Departments of Dermatology (IVDK, http://www.ivdk.org) between 1992 and 2004.

RESULTS

Analysis of 79 365 patients patch tested with pure petrolatum yielded 27 '+' (0.03%) and 2 '+++' (0.003%) reactions. The majority of non-negative reactions (0.3%) was interpreted as doubtful (235) or mild irritant (32). The negative reaction index (RI) (-0.8), and the high positivity ratio (PR) (93%) especially a lack of concordance with patch test preparations containing > or=99% petrolatum indicate that many of the 'positive' (+) reactions have to be considered as irritant. There were 2 '+++' reactions. In 1 case, an 'angry back reaction' was confirmed. The other case is probably a reading or documentation error, as the majority of patch test reactions to preparations containing petrolatum remained negative in this case also.

CONCLUSIONS

True allergic patch test reactions to white petrolatum are extremely rare and probably due to an individually increased susceptibility to allergens and/or irritants. This is in agreement with considering petrolatum as a non-sensitizer.

Allergic contact dermatitis from pyoctanin

Although pyoctanin is widely used in medicine, there are hardly any reports of contact allergy to it. Most reports of side-effects refer to irritant reactions after topical application. We describe 2 patients who developed pyoctanin contact dermatitis after long-term application on damaged skin. Positive patch test results down to concentrations of 0.0025% and 0.05% aqueous pyoctanin solution, respectively, were found.

Compound allergy to a skin marker for patch testing: a chromatographic analysis

We present details of a patient who was demonstrated to have contact allergy to a solution used to mark sites of application of patch tests, during investigation of allergy to gold and nickel. Negative results were obtained when patch testing was performed using the individual constituents of the marker solution (gentian violet, dihydroxyacetone and acetone). Chromatographic analysis of various combinations of these chemicals did not identify a chemical derivative which might have caused this reaction.

Tropical ulcer--a reappraisal based on recent work

Tropical ulcer is a disease which predominantly affects young children in the tropics. The course of the disease can be interrupted in the early stages by the administration of antibiotics so it seems likely that infection may play a role. The disease extends rapidly from the initial lesion, a tiny papule, to a large area of necrosis. This makes a toxic factor likely in the pathogenesis. The epidemiology and some of the causative factors of this disease are currently being investigated. Patients with tropical ulcers were assessed, in areas where the disease is still endemic (Gambia, Papua New Guinea, southern India and Fiji), by a paediatrician or a dermatologist. All patients had swabs taken from the ulcers for bacteriological examination. Skin biopsies were taken from the edge of the ulcers as often as possible. The bacteriological samples were transported anaerobically to London where the laboratory work was performed. The results are discussed in relation to previously reported work.

Contact dermatitis in patients with leg ulcers. The prevalence of late positive reactions and evidence against systemic ampliative allergy

100 patients with leg ulcers were patch tested against a standard battery of allergens. The readings were carried out daily from the 2nd to the 7th days. 55 patients showed positive reactions to one or more allergens. 32% of positive reactions developed for the first time after 48 h and 11% after 72 h. No single day or combination of two days gave 100% positive results. A single reading on the 4th day gave the highest number of positive reactions at 92%. The prevalence of positive patch tests was significantly higher in patients with surrounding eczema, and in patients with positive patch tests the ulcer duration was significantly longer than in those with negative patch tests. The total number of positive results in individuals increased linearly with the duration of the ulcer. Of allergens to which the ulcer was exposed, the occurrence of multiple sensitivity was significantly greater than predicted from the prevalence of individual sensitivities. However, there was no association between medicaments and metal sensitivity. This, together with the absence of an exponential rise in the number of allergens with the duration of ulcer, does not support the theory of systemic ampliative allergy.