Diagnosis. Prognosis. 975 



peculiar copper-red color appears especially important diag- 

 nostically, further the thickening of the skin, together with a 

 marked diminution in elasticity, also the pustules situated in 

 the depths of the skin, mostly bluish red in color, and itching 

 which is at most only slight. All these signs enable one to 

 differentiate the disease easily from primary acne, sarcoptic 

 scab, distemper, exanthema and from simple eczema. In the 

 other species of animals relatively large, hairless and reddish 

 nodules with thick contents awaken a suspicion of acariasis, 

 yet the disease may be recognized positively only by the micro- 

 scopic demonstration of the mites. 



The squamous form is far more difficult to differentiate 

 from other affections. Apart from the localization of the dis- 

 ease or its appearance at the same time on several parts of the 

 body,^ the best conclusion can be formed by the microscopic 

 examination of the fluid substance extruded by lateral pressure 

 on the raised folds of skin, or of the skin scrapings. (Since in such 

 cases the mites are present in the hair follicles only sparingly, 

 a single test is not always sufficient.) In this form of acariasis 

 one must exclude especially circinate ringworm, favus, eczema, 

 such as that caused on the eyelids through conjunctival catarrh 

 (distemper), also sarcoptic scab and alopecia. But every fall- 

 ing out of the hair in the dog without traceable cause must ap- 

 pear suspicious in this connection. As regards the differential 

 diagnosis between sarcoptic scab and acariasis one should fur- 

 ther bear in mind that both skin affections can be present simul- 

 taneously in the same dog. 



Prognosis. In the large animals a spontaneous cure of the 

 disease appears to be possible, also at times in dogs when the 

 attack is slight ; Uebele has repeatedly seen spontaneous healing 

 in spite of extensive acariasis, and this is said to be the rule in 

 the diffuse affection in young terriers, which is called distemper 

 rash ])y breeders. On the other hand permanent healing can, 

 in case of extensive eruption, be secured only rarely, even by 

 proper treatment, and sometimes even when the disease is not 

 very extensive, because the mites live deep under the surface 

 of the skin and therefore it is difficult to destroy them with 

 parasiticides, and besides secondary infection with staphylococci 

 has often already occurred. As a matter of fact, not infre- 

 quently dogs that are apparently cured suffer renewed attacks 

 after weeks or months. At times, however, complete cure or a 

 marked improvement is noticed without any treatment. 



In pustular acariasis of carnivora the prognosis is un- 

 favorable; it therefore appears most expedient to kill such ani- 

 mals. A much more favorable opinion may be given in the 

 squamous form where the complaint is limited to a small area, 

 yet even here one should always reckon with the possibility of 

 a further extension, and therefore be cautious in giving a prog- 

 nosis, all the more so as even quite trivial and apparently slight 



