Posted by Librarian on 4/2/2002, 12:24 pm

I have had some further correspondence with Mrs. X on this subject. The last letter, written several months ago, indicated that she was still suffering from the effects of the parasites, and that nothing prescribed by doctor or dermatologist had been of permanent value in controlling her trouble. On the theory that English sparrows nesting under the eaves might have brought the mites into their home, the family had had the entire house fumigated, repainted and repapered and still Mrs. X suffered from the mites. The other members of her family had meantime recovered from their unpleasant experience with the arthropods. Here, then, is another instance in which humans, attacked by mites other than Sarcoptes, have received scant attention from the medical profession. Had Mrs. X not been fortunate enough to capture the two mites, she might really have come to believe that she did have a "phobia," whatever that expression may be taken to mean. And even with the causative agent at hand, and identified, the dermatologist was unable to treat the infestation successfully. A certain parasitologist, in conversation on the subject of mites, has told me that he has had several experiences similar to the above, in which persons fairly frantic from the attacks of some unknown creature had been unable to obtain aid from their doctors, and had written him or come to him for help. What, on the other hand, could a medical adviser or dermatologist prescribe, in the present state of our lack of knowledge, in such a case? So little is known of the activity and behavior of many mites that may occasionally infest man, and so little also as to the effective methods of treatment. This is, I believe, a subject which is in great need of further investigation. I suggest that the medical profession might do well to take the lead in such a study. The mite dermatophagoides scheremetewskyi Bogdanow, a member of the family Epidermoptidae, is herewith reported as attacking humans, infesting the scalp as well as other parts of the body. Its behavior is not similar to that of such mites as Sarcoptes. It is believed that the mites burrow down into the dermis, in which they make their runways, and that they occasionally come to the surface from these runways. In general, movements of the mites from place to place are believed to occur within the shelter of these runways. To date, no treatment employed against the mite has been completely effective, in the sense of killing the ova as well as the adult mites. Nor has repeated re-application of any of the substances used, proved effective in eradication. Many different substances known to be highly effective against Sarcoptes and Notoedres have been employed as scabicides over the past seven years, in attempts to bring about control or eradication of the mites. Of these, the old standby, sulphur ointment 15%, is the one to which we return again and again, after other substances have failed. Yet it, too, has been unable to eradicate these arthropods. Three compounds which have been most recently used, benzyl salicylate, 2-phenylcyclohexanol, and benzyl benzoate used at double strength, may perhaps be the answer to our problem, but it is still too soon to know. Certain other substances known to be effective against sarcoptic scabies have proved of little value in the treatment of Dermatophagoides. Among these are tetraethylthiurum monosulfide, and benzyl benzoate used at the usual strength. The infestations here reported have lasted ofver a period of at least seven years, and have occurred on three adult members of the same family. The source from which the infestation was originally obtained is unknown. If, as we surmise, infested cats or a dog suffering from mange may have been the source or sources, there has been no chance for reinfestation for some years, as these animals have long since died. But there is no certainty that the "mange" from which they suffered was produced by the same causative agent as that which has infested us. It seems probable that the human infestation has lasted for this period of time due to continued self-reinfection of each individual concerned, since the ova are apparently never destroyed by any treatment we have employed. It should be noted that the mites seem to thrive on cleanliness, if weekly, sometimes semi-weekly, shampoos during the entire period of time can be used as a criterion. The mites, be it recalled, occur principally on the scalp. It is to be hoped that members of the medical profession may soon come to realize that it is possible for humans to be infested with mites other than Sarcoptes, give the patient the benefit of the doubt and try to determine the real cause of the ailment. It is not too easy for a person infested with said mites to make a diagnosis himself, nor to prescribe treatment if he is fortunate enough to locate the causative agent. The medical adviser and the dermatologist, on the other hand, are in a position to add much valuable information in regard to the habits and activities of this and other human-infesting mites, as well as to determine methods of control or eradication, if only they are willing to do so. We can but echo Bogdanow, when he states: "Il serait a desirer que les observations prochains de M. Scheremetewsky et des autres dermatologues nous donnent plus des details sure les acaricides, parasites de la surface de la peau de l'homme." Had it not been that the writer of this article was (1) unwilling to accept the dermatologist's verdict of "Just imagination";(2) had sufficient knowledge of parasitology and access to enough literature on this subject so that she was able to proceed "on her own" in quest of the invading organisms; and (3) knew how to preserve and mount the mites when found, this mite would in all probability not have been located, and the difficulties experienced would never have been attributed to their real cause. It is quite possible that the mite Dermatophagoides infests humans more often than anyone has known, but that its attacks are usually of a minor order, so that the itching and other annoyances caused by its presence may be attributed by the human host to (1) "imagination," as the doctors would have us believe; (2) "summer heat," since the mites are most active during hot weather; or perhaps (3) "dandruff." A wide-open field exists for anyone enterprising enough to do some real investigation on this subject. The presence of the mite Bdellonyssus sylvarium as a causative agent of dermatitis in the human scalp and on the human body is likewise reported. At last reports, the unfortunate host of this mite was still suffering from its depredations. In this case, the diagnosis has been: "Just a phobia." Here is another field in which to date there has been no competition in the matter of studying the mite as an occasional human parasite.