Primary toxic reaction

One application of 5% PNDMA in vaseline to the neck of unsensitized guinea pigs produces nothing unusual but if the number of applications is increased, lesions appear redness, squames and crusts. Under histological examination, we observe epidermal changes (extracellular edema, vesicles, necrosis) and an infiltrate which is composed of lymphocytes and leucocytes. 

One application of 1 % PNDMA in olive oil produces no visible change on the flank or on the nipple under both macroscopic and histological examination after 3, 6 or 14 hours. 

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The technical conditions in which patch tests are performed for the specific reaction of sensitization as well as for the primary toxic reaction must be well determined ... 

By intraganglional administration. Seeberg (1951) sensitized a certain number of animals but the concentration of the solution of DNCB used in this test is high (1 %), see p. 7 primary toxic reaction. 

Primary Toxic Reaction in Unsensitized Guinea Pigs 7... 

Determination of the minimum primary toxic concentration of DNCB in guinea pigs is absolutely necessary before undertaking the sensitization and the interpretation of the tests. In fact, there are important differences of opinion in the literature concerning the primary toxic reaction of DNCB. 

In our experiments on the primary toxic reaction, we used a 1% solution of DNCB in acetone, which gives a well defined erythematous reaction after 14 hours (patch test for a primary toxic reaction). 

However if a 2% solution of DNCB is applied on the flank with acanthosis, primary toxic reaction is also observed (sub-epidermal bullae, necrosis), but to lesser extent than on the flank without acanthosis. 

The primary toxic reaction of DNCB has been histologically examined by various authors. Among others ... 

Fisher and Cooke (1958) observed the development of a primary toxic reaction by applying, on the skin of normal guinea pigs, DNCB in olive oil in concentrations of 2%, 3% and 5%. ... 

According to results obtained by various authors and ourselves, the concentrations sufficient to give an interpretable patch test, but hardly ever a primary toxic reaction, are for DNCB solutions ... 

As for the primary toxic reaction, not only the concentration of the allergen, but also the solvent, must be taken into consideration for the test. Solutions of DNCB diluted in oil are less potent than alcoholic or acetonic solutions. 

It seemed also (de Weck and Brun, 1957) that the course of the reaction was slightly modified by the acanthosis. After 24 hours the lesions on the acanthotic nipples were clearly less significant. Nonetheless, the histological differences observed between the reactions on the flanks and nipples with or without acanthosis do not permit us to affirm that acanthosis plays a protective role against the triggering of an eczematous reaction in animals sensitized with DNCB. . . . But we should keep in mind that under certain conditions, acanthosis can have a protective effect relative to the primary toxic reaction (see p. 8). 

We did not observe a primary toxic reaction either under macroscopic or under histological examination, after applying 10% paraphenylenediamine in vaseline on the flank or on the nipple. 

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