Acanthosis flank

In order to obtain an acanthosis of the epidermis of the flank, a non-greasy cream is applied 8 times within 10 days on the flank which has been previously shaved this causes significant acanthosis of the epidermis. 

In applying a 1 % solution of DNCB on the flank without acanthosis, the primary toxic lesions already described are observed after 24 hours (sub-epidermal bullae, necrosis of the epidermis, infiltration), whereas on the flank with acanthosis there are practically no lesions (Fig. 4a and b). 

Fig. 4a and b. Application of 1 % DNCB on the flank of non sensitized guinea pig. a No acan-thotic flank strong alterations, b Acanthotic flank (acanthosis induced by erucic acid) no... 

In guinea pigs sensitized with DNCB, the reactions obtained on the flank with acanthosis are more typical and easier to interpret than those obtained on the flank... 

We have repeatedly observed on the flank with acanthosis, in addition to spongiosis (Fig. 7), the presence of alterations cavitaires , already described in 1890 by Leloir as typical of eczema in man. 

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). 

After 3 applications there are no eczematous lesions, on the nipple, or on the flank and no acanthosis is observed. 

After 8 applications, spongiosis appear on the epidermis of the flank and even more so on the epidermis of the nipple. A light dermal infiltrate of similar appearance is evident both on the flank and on the nipple there is a clear acanthosis on the flank, but its appearance on the nipple is difficult to note in view of the intensity of the eczematous, epidermal lesions. 

After 10, 12 and 16 applications, the eczematous lesions increase in number and intensity, as much on the flank as on the nipple. Acanthosis of the flank increases steadily. 

We have seen elsewhere that if one applies daily a solution of 0.1% DNCB in acetone to a single nipple of a nonsensitized guinea pig (5, 8, 20 applications), acanthosis increases regularly on this nipple at the same time as the eczematous lesions are developing. Some eczematous lesions also appear and progressively grow in intensity on the flank and the other nipple, after a patch test (0.1% in acetone) (Table 5). 

Rajka and Hard (1960) applied a solution of 0.1 % DNCB in alcohol 3 times a week for 1 year to the flank of a previously sensitized guinea pig, and they examined the treated places every 2 weeks. They observed that the acanthosis remained unaltered during this treatment. They also attributed this acanthosis to the allergic reaction triggered by the allergen (DNCB). 

DNCB 0.1% (in acetone) on the left nipple weight approx. 250 g flank right nipple not previously treated spongiosis left nipple previously treated (i applications) spongiosis multiple acanthosis... 

Fig. 16. Guinea pig sensitized to PNDMA. Flank 14 hours after a single application of 1 % PNDMA in olive oil acanthosis, no epidermal lesions...

In a second group of sensitized guinea pigs, some also exhibited this acanthosis. On the contrary, in the others which did not present an acanthosis of the flank, we found small but distinct spongiosis (Fig. 17). 

Fig. 30. a Guinea pig sensitized to DNCB. Acanthosis of the flank (due to X-rays) 14 hours after a single application of O.T ) DNCB in acetone a few epidermal alterations, no spongiosis. b Guinea pig sensitized to DNCB. Acanthosis of the flank (due to crude acid) 14 hours after a single application of 0.1% DNCB in acetone spongiosis... 

After a sufficient lapse of time following an irradiation of 1600 R on the flank of normal guinea pigs, the acanthosis disappears and, except for the absence of hair follicles, the skin appears completely normal. If a patch test is performed after the guinea pigs have been sensitized, there is almost no macroscopic reaction, nor is there a histological reaction comparable to that observable on the non-irradiated flank (Maggiora, Bujard, W. Jadassohn, 1967, Fig. 31a and b). This proves once more that the acanthosis is not responsible for the diminished reactions on the X-ray treated flank. 

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