OTHER ANIMAL PARASITES, OF MINOR IMPORTANCE, ATTACK­
ING OR IRRITATING THE SKIN

Brown-tail Moth

The brown-tail moth (Euproctis crysorrhœa) is a comparatively recent acci-
dental importation into Massachusetts from Holland, it is said, along with some
roses, destructive to fruit trees and probably other vegetation. It has now already
spread over New England, a part of Canada, and westward, and has received the
attention of those interested in agriculture.¹ At about or shortly after the time of its
introduction J. C. White² reported a number of cases of dermatitis due to a caterpillar,
to which first Meek³ and later Towle,⁴ Spear,⁵ Tyzzer,⁶ Potter,⁷ and others have added
their observations. It has now been shown that the “nettling” hairs of the brown-
tail moth, its cocoon, and caterpillar are responsible for a considerable number of cases
of cutaneous irritation (brown-tail moth dermatitis) of somewhat variable character and
degree.

Symptoms.—The first symptom is usually itching, following a short time after
exposure, as a rule within a half-hour; and the appearance of discrete erythematous

¹ Fernald and Kirkland, “The Brown-tail Moth,” Bull. Mass. State Bd. Agricul-
turer, 1903; Fifty-second Ann. Rep. Sec’y Mass. State Bd. Agricult., 1904; “Nature
Leaflet, No. 26,” ibid., April 2, 1908; Ann. Rep. Sec`y Agricult., Nova Scotia, 1908.

² J. C. White, “Dermatitis Produced by a Caterpillar,” Boston Med. and Surg. Jour.,
1901, vol. cxliv, p. 599.

³ Meek, “Further Observations on the Brown-tail Moth,” ibid., p. 657 (correspond­
ence).

⁴Towle, “The Brown-tail Moth Eruption,” ibid., 1905, vol. clii, p. 74.

⁵ Spear, “Brown-tail Moth Eruption,” ibid., p. 121 (correspondence).

⁶ Tyzzer, “The Pathology of the Brown-tail Moth Dermatitis,” Jour. Med. Re­
search, 1907, N. S. xi, p. 43 (with plate); and Trans. Internat. Dermat. Cong., 1908, vol.
i, p. 169.

⁷ Potter, “Brown-tail Moth Dermatitis,” Jour. Amer. Med. Assoc, 1909, vol. liii,
p. 1463.

1182

PARASITIC AFFECTIONS

macules which rapidly become urticaria-like efflorescences, or they may begin as the
latter. They are about pea-sized, raised, rather firm, but may be made to disappear
momentarily upon pressure. The lesions instead of being discrete may be irregularly
grouped or crowded together; or there may be, in more severe cases, a more or less co-
alescent inflammatory redness, and some swelling, with an accentuation here and there,
either in spots or patches. Occasionally the dermatitis is eczematoid, exceptionally
with even associated fissuring. The degree of the reactionary irritation depends largely
upon the amount of the irritating material as well, doubtless, to some degree upon the
character and vulnerability of the individual skin. The itching is always more or
less troublesome, sometimes quite intense. According to the severity of the case,
the eruption may last from a few days to several weeks or longer. The face, neck,
arms, and upper part of the trunk are favorite situations; it may be limited to several
small scattered or grouped spots, or to a small area, or
involve one or more of these regions; exceptionally,
from infested clothing, it may be somewhat general.
In some of the general cases systemic symptoms of a
mild toxemia may develop.

Fig. 316.—Brown-tail moth, female (Fernald- Fig. 317.—Brown-tail moth cater-
Kirkland).                                           pillar (Fernald-Kirkland).

The malady is most frequently seen about the time the caterpillar reaches its
full growth—in the latter part of May and June—but it may be met with before or
after this time; in fact, at any period of the year from wearing clothing in which the
hairs had previously become lodged. The active factor in the production of the
cutaneous irritation is to be found in the minute nettling barbed hairs, most numerous
on the caterpillar, but also present on the cocoon and on the moth; usually by immediate
contact, but also by handling plants or vegetables upon which hairs have become lodged;
doubtless, too, these hairs occasionally may lodge upon the skin along with the dust of
the air. The epidermis and sometimes the upper corium are pierced by the barbs, occa­
sionally probably going more deeply. While at first this irritation was thought to be
purely mechanical, Tyzzer’s experiments indicate that it is largely due to the action of
some irritative substance contained in the penetrating hairs; Tyzzer found experi­
mentally that this substance produces some reactionary changes in the red blood-œr-
puscles. There is found necrosis of the epidermis around the nettling hair, and in most
instances there is exudation of fluid into the epidermis (Tyzzer).

Treatment consists in the use of soothing and antipruritic lotions and ointments,
such as prescribed in other forms of dermatitis, pruritus, and eczema—carbolized
lotions and ointments being most frequently employed. It is sometimes quite persist­
ent and rebellious, due, doubtless, in such instances to the fact that the hairs may be
somewhat deeply imbedded. My colleague, Professor Holland, who spends the sum­
mer along the eastern shore, tells me that the treatment found most successful consists
in the use of a mercuric chlorid lotion (1 : 1000 to 1 : 2000) and the painting of each spot
with flexible collodion.

PEDICULOIDES VENTRICOSUS

1183

Pediculoides Ventricosus¹

(Producing a dermatitis variously described or named: Grain-mite dermatitis; Straw
itch (Rawles); Grain itch, acarodermatitis urticarioides (Schamberg); Grain derma­
titis; Barley itch (Wills); Mattress itch; Straw-packers’ itch; Straw dermatitis; Derma­
titis urticarioides parasitica; Prairie itch, etc)

For some years occasional reports (Lagréze-Fossot and Montané, ,Rouyer, Geber,
Koller, Moniez, Fleming, Pascal, Ducret, Sberna, and others) in European countries
of small epidemics of an eruption, consisting usually of discrete, scanty to thickly set
erythematopapular and papulovesicular lesions of micro-urticarial and microvaricelli-
form characters, have appeared from time to time, and attributed to a small parasite—
the pediculoides ventricosus—sometimes found infesting straw and grain. In this
country, in the past few decades,² groups, usually family groups, of cases of similar
eruption have also been noted (first by Schamberg), more particularly in Philadelphia

¹ Important literature of pediculoides ventricosus and of the dermatitis provoked
by it: Newport, “An Account of a New Acarus (Heteropus ventricosus): A Parasite in
the Nests of the Anthophora retusa,” Trans. Linnean Soc’y of London (read March 5,
1850), 1853, vol. xxi, p. 95; Lagrèze-Fossot and Montané, “Sur la mite du ble’,”
Registre agronom. de la Soc. des Sci. d` agricult. et bell. lett. du Tarnet-Garome, 1851, xxxii,
No. 2; Rouyer (through Robin), “Eruption cutanée due a l’acarus du ble’,” Compt.
rend, des seances de la Soc. de Biolog., 4,1867, p. 178; Geber, “Eutzündliche Prozesse der
Hant durch eine bisher nicht bestimmte Milbenart verusacht,” No. 43, Oct. 26, 1879,
pp. 1361, 1395, and 1428; “Observations on the Angoumois Grain-moth and its Para­
site,” Report of State Entomologist of Illinois, Nov. 20, 1883; Targionni-Tozzetti, An-
nali di Agricoltura, Italy, 1878, vol. 1; Laboulbène and Mégnin, “Mémoire sur le Sphæro-
gyna ventricosa (Newport),” Jour, de l' Anat. et de Physiol., 1885, xxi, p. 1 (with plate
of illustrations of parasite); Flemming, “Ueber eine geselechtsreife Form der als Tarso-
nemus beschriebenen Thiere,” Zeitschr. für die ges. Naturwissenschaften (4), 1884, iii, p.
472, Halle; Koller, “Neue Fälle eines durch einen Getreidschmarotzer verusachten
Hautausschlages,” Pester med.-chir. Presse, No. 32, 1882; abs. in Archiv, 1882, p. 511;
and Biolog. Centralbl., 1885, iii, p. 127; Geber, Ziemssen’s Handbook of Skin Diseases,
1885, p. 555; Karpelles, “Eine auf dem Menchen und auf Getreide lebende Milbe,”
Anzeiger der K. K. Akad. der Wissensch. zu Wien., 1885, xxii, p. 160; R. Blanchard,
Traite de Zoologie medicale, Paris, 1890, vol. ii, p. 284; Brucker, “Sur Pediculoides
Ventricosus (Newport),” Compt. rend, de la Soc. de Biol., 1899, p. 953, and Bull. Sci.
de la France et Belg., 1901, t. 35, p. 365; Pascal, “Erythéma scarlatiniforme desquamatif
generalisé d’origine parasitaire,” Annales, 1900, p. 947; Moniez, “Sur l’habitat normal
dans les tiges d. céréales d’un parasite accidentel de l’homme,” Rev. biolog. du Nord. de
la France, 1895, vii, p. 148, and Traite de Parasitologie, animale et végétale, applique a
la Médicine, Paris, 1906; Cambillet, “Epidémie d’urticaire provoquée par l’aleurobius
farinæ,” Jour. mal. cutan., 1908, p. 546; Ducrey, “Acariasi da grano, in forma epidemica,
dovuta al Pediculoides ventricosus,” Processi verballi. Soc. Ital. di Dermat. e. Sifil. (Dec
16-19, 1908, in Rome), Milan, 1909, pp. 93-122 (review, with references); Sberna,
“Dermatosi accidentale du acari della tignola del grano (pediculoides ventricosus”),
ibid., pp. 122-138 (review and bibliography); Wills, “Barley Itch,” Brit. Jour. Derm.,
Aug., 1909; Max Braun, “Animal Parasites of Man,” 1906, New York.

Schamberg, “An Epidemic of a Peculiar and Unfamiliar Disease of the Skin,” Phila.
Med. Jour., July 6, 1901 (with several case illustrations); and “Grain Itch (Acaro-
dermatitis Urticarioides): A Study of a New Disease in this Country,” Jour. Cutan.
Dis., Feb., 1910 (a complete exposition and review, with excellent illustrations and refer­
ences) ; Goldberger and Schamberg, “Epidemic of an Urticaroid Dermatitis Due to a
Small Mite (Pediculoides ventricosus) in the Straw of Mattresses,” Public Health
Report, No. 28, Washington, D. C, July 9, 1909; and Rawles, “Straw Itch,” Indiana
State Med. Jour., Aug., 1909.

² It would seem, however, that the malady was noted some years earlier: Harris,
“The Report of Insects Injurious to Vegetation,” Boston edition of 1852 (also cited by
Schamberg), curiously shows that the association of straw (straw mattresses) and an
eruptive condition was noted in 1829 and 1830 in Eastern New England, as indicated by
several communications regarding the matter in Fessenden’s New England Farmer.
In Philadelphia the first cases came under my own observation in the autumn of 1889,
consisting of a group of a mother and two children; only a few cases yearly were after­
ward seen by me till 1900-02, when they presented in moderate numbers, always in
family groups; since that time it has been less uncommon, and especially in certain years.
Although recognizing them as unusual cases, and probably due to an unknown parasite,
they were provisionally classified as “vesicopapular urticaria.”

1184                               PARASITIC AFFECTIONS

and nearby States westward; Goldberger and Schamberg, and, almost simultaneously,
Rawles, were the first to associate convincingly cause and effect, and to identify the
organism; Schamberg’s investigations being extensive and conclusive. An examina­
tion of the reports made from the West and South, some years ago, of so-called prairie
itch, swamp itch, Ohio scratches, Texas mange, lumbermen’s itch, etc, leads to the
conclusion that at least some groups of these cases¹ were examples of dermatitis due to
this same cause.

Symptoms.—The eruption usually presents itself rapidly, preceded by and asso­
ciated with itching. The lesions at first appear, as a rule, as small to large pea-sized
erythematous spots, which may not be materially elevated, or may be more or less
typical hives, but rarely very large in size; within a short time, at the very central
point, there appears a papulovesicular or vesicular formation, which in the course of a
day or two shows some milkiness and frequently becomes slightly purulent, occasionally
distinctly so. These vesicles or vesicopapules remain, for the most part, small, scarcely

Fig. 318.—Grain-mite dermatitis (courtesy of Dr. J. F. Schamberg).

larger than an average pin-head. As the lesions thus advance, the urticarial aspect
measurably, sometimes almost entirely, subsides. The tops of some of the scratched or
broken lesions are apt to show a minute blood crust. If the cause has ceased to act, the
eruption soon begins to dry up, the lesions becoming surmounted by a thin crust or
scale, which finally falls off; and in one to three weeks the malady is usually at an end.
If the patient continues, however, exposed to the cause, new eruption keeps coming
out, and it may so persist a month or more. The foregoing is the type most commonly
seen, simulating somewhat a vesicopapular urticaria (lichen urticatus); and if there are
intermingled distinct pustules, from accidental infection, it bears some resemblance,
except as to distribution, to scabies. In exceptional instances this additional pyogenic

¹ The statement made by one writer that he believes it “associated with decaying
hay and straw,” and that of another, that “men who go with threshing machines seem
to have it generally,” are very suggestive.

PEDICULOIDES VENTRICOSUS

1185

element, together with the scratching, may result in giving the eruption, in one or more
places, an eczematoid or even an impetiginous aspect. Occasionally the vesiculation is
more pronounced and the vesicles somewhat larger, and in such instances it offers a
distinct suggestion of varicella—a microvaricella—the lesions being somewhat smaller
than in ordinary varicella. Only exceptionally are cases met with in which the erup­
tion consists of erythematous spots only—the erythema type—and which may in places
be so close together as to seemingly coalesce. In other instances the lesions do not get
beyond the urticarial development. The lesions are, however, rarely typical wheals,
but are usually smaller, and, as a rule, are pinkish or reddish in their entirety, lacking
the whitish central portion which commonly characterizes the true wheal of urticaria.
The eruption varies in amount—there may be but twenty to forty lesions in some cases
and uncountable numbers in others; it is moderately abundant in the average case.
There is no tendency to actual coalescence, except occasionally as the result of scratch­
ing and additional pyogenic infection. The eruption is most commonly seen upon the
trunk, especially the upper two-thirds, on upper part of the arms, and on the neck;
but it may involve, in addition to these regions, the upper part of the thighs and face,
and, exceptionally, is practically generalized. Itching is often a troublesome feature.
In well-developed cases there is not infrequently, in the first few days, slight
febrile action, with other mild systemic symptoms. Rawles and Schamberg noted

Male.                                Young female.                      Gravid female.

Fig. 319.—Pediculoides ventricosus, greatly enlarged (Laboulbène and Mégnin).

slight albuminuria in a small proportion of their cases, and the latter observed a moder­
ate leukocytosis in most patients and a well-marked eosinophilia in many.

Etiology and Pathology.—All ages are liable. It is most commonly seen during the
warm months. It is met with in those who come in contact with infested straw or
grain—either by sleeping on mattresses containing such straw or by handling such grain
or straw. It has occurred in those unloading bags of grain and in packers who use straw
packing. It may thus find its way to the human subject by direct contact with these
substances or through accidentally infested apparel or other articles. The irritating
agent is a small mite, first clearly identified by Newport (1850) and since by others;
and is now known by the accepted name of “pediculoides ventricosus,” of the class
Arachnida and of the order Acarina or mites. It can usually be detected in the dust
of the straw or grain with a magnifying glass of moderate power. Its characteristics
are well depicted in the accompanying cuts.¹ Whether it is always the same species

¹ The mite has four pairs of legs. The male is oval in shape, 0.12 mm. in length, and
0.08 mm. in breadth, is flattened, has six pairs of chitinous hairs on the dorsal surface
and a lyre-shaped lamella on the posterior part. The non-gravid female is cylindric in
form, 0.2 mm. in breadth, and 0.07 mm. in length; when gravid the posterior part of
the body becomes ball-shaped up to 1.5 mm. in size. They reproduce rapidly, the
young being sexually mature almost as soon as born.

75

ii86

PARASITIC AFFECTIONS

that produce the trouble is not definitely known. It is usually only found where there
are grain-destroying insects, being predatory and parasitic upon them; although they
doubtless may live on the straw and grain also. They do not burrow in the skin, as
does the itch-mite, but probably only pierce it momentarily for the purpose of nourish­
ment, and apparently at the same time injecting a toxic substance. The pathologic
changes in the skin are those characteristic of the lesions of urticaria (Schamberg).

Diagnosis.—The suddenness of the outbreak, the intense itching, and, usually,
its appearance in seemingly epidemic or group form, the distribution, and the uniformity
of the lesions, are extremely suggestive; add to this the history of contact with straw or
grain, and the inference is more or less conclusive. The distribution is different from
that in scabies, and the latter begins insignificantly, insidiously, in fact, and is only
slowly progressive; in grain-mite dermatitis the eruption develops almost at once and
rapidly. It is in those cases that persist from continued exposure to the cause that may
at times give rise to some confusion with scabies. The vesicles in chicken-pox are much
larger, the eruption rarely so abundant, and itching scarcely present, or at the most
slight; the scalp is quite commonly the seat of some lesions, whereas this region is
rarely attacked in grain-mite dermatitis. The eruption in urticaria of small papulo-
vesicular nature is comparatively scanty and the limbs are its usual site.

Prognosis and Treatment.—Upon removal of the cause, disinfection of the mattress,
bedding, and wearing-apparel, frequent baths, and the application of mild antiprüritic
lotions or ointments, the malady comes gradually to an end, usually in from one to two
weeks. The carbolized calamin-zinc-oxid lotion and a carbolized Lassar’s paste (see
Eczema) are both useful. Schamberg speaks well of an ointment of betanaphthol and
sulphur, of about one-half the strength employed in scabies. Repeated exposure to the
infested mattress or other infested straw or grain is responsible for long-continued cases;
although, even when disinfection is not practised, the mites apparently finally die or
become innocuous, and the patient sooner or later recovers.

Cimex lectularius (acanthia lectularia, Fr., punaise des lits; Ger., Bettwanze),or,
as commonly called, the bed-bug, is a well-known insect, universal in its distribution,
which can produce a good deal of cutaneous mischief. It simply goes to the skin for
nourishment, puncturing it and sucking blood; it is said to inject an irritating fluid to
increase the flux of blood to this point. An inflammatory papule or wheal-like lesion
most commonly results, having often a purpuric tendency, especially at and about the
point of puncture. This purpuric or hemorrhagic point or spot remains after the swell­
ing subsides, but finally, in the course of several days or a few weeks, disappears. Very
frequently the insect makes several punctures at but short distance apart, so that the
lesions are sometimes seen as an irregular group of three, four, or more, and are often
covered over with a blood-crust. The legs, especially in the neighborhood of the ankles,
are a favorite point of attack, probably because nearest the joints or crevices of the bed.
The resulting irritation varies considerably in different individuals, in some nil, and
in others extremely severe and lasting. The hemorrhagic, wheal-like papules may be­
come pustular and show a good deal of underlying and surrounding inflammation. The
condition is not to be confused with urticaria, to which it bears some suggestion, es­
pecially if the lesions are somewhat numerous and scattered. The hemorrhagic tend­
ency, central puncture, and persistence of the bed-bug lesions are not seen in urticaria.

Treatment consists in the use of alkaline and carbolic acid lotions, with carbolized
ointments if necessary. The various other lotions employed in urticaria are also ser­
viceable.

Pulex irritans (Fr., puce commune; Ger., gemeiner Floh), or common flea, is of
somewhat general distribution, but more common in some regions, especially in tropical
climates; it is capable of exciting varying degrees of irritation. The most usual lesion
is a small, ring-like, erythematous spot with a minute, central, hemorrhagic point,
marking the place of attack. In exceptional instances the purpuric character has been
sufficiently pronounced as to suggest purpura simplex. In some people the lesion is

PEDICULOIDES VENTRICOSUS

1187

scarcely perceptible and gives rise to no discomfort. In others, who seem to be espe­
cially vulnerable to “flea-bites,” the resulting lesion is urticarial in character, and more
or less persistent, markedly itchy, tender, and painful, with sometimes a fiery, burning
feeling. Several or more are frequently to be seen close together, or strung out, marking
the travels of a single parasite. When the latter are present in any number, suscep­
tible individuals may suffer somewhat intensely, and may even show some general dis­
turbance. Many American travelers in Europe suffer considerably from this pest, the
“foreign flea” seeming to be especially damaging to the American skin, although such
individuals are often unaware of the character of the trouble, believing it to be urticaria
due to change of food, etc The lesions in those of sensitive skin resemble those of
the latter malady, but the recent spots usually show the minute central hemorrhagic
point.

In the treatment the various carbolized, thymol, and alkaline lotions employed in
urticaria, pruritus, and eczema are of value in relieving the irritation, and their use
makes the skin a less attractive feeding-ground for the parasites. In those especially
vulnerable to these pests, particularly women, whose manner of dress permits easy
access, the wearing of a lump of camphor enclosed in a cheese-cloth bag under the cloth­
ing will sometimes furnish variable protection; in extreme instances the wearing of
several small, loosely woven bags containing pyrethrum powder, pinned on at different
parts of the underwear, will often keep up an efficient atmosphere of protection against
attacks.

The ixodes (Fr., pou de bois; tique; Ger., Holzbock; Zecke), or wood-tick, is a
minute parasite which is sometimes parasitic on man, and of which there are several
species. It is generally found on bushes or trees, and occasionally drops on an oppor­
tune subject to secure blood. In its attack it sticks its proboscis in the skin and sucks
blood until several times its natural size, and then falls off; an urticarial lesion marks the
site, sometimes more or less persistent, itchy, and painful. If the parasite is caught
in the act of attack, it should not be forcibly extracted, as its proboscis may thus be
broken off and remain in the skin, and give rise to considerable pain and inflammation.
It may be made to relinquish its hold by placing on it a drop of an essential oil or
moist tobacco. A thymol or carbolized boric acid lotion will relieve the irritation.

The dermanyssus avium et gallinæ (bird-mite; fowl-mite; chicken-louse; Fr.,
dermanysse des oiseaux; Ger., Vogelmilbe) occasionally attack the human integument
and provoke a varying degree of erythematous and papular irritation, which is often
added to by the scratching induced. The parasite is small, about the size of a grain of
sand, grayish white in color, with six three-jointed legs, no antennae, but strong man­
dibles. They are quite a pest among fowls, and sometimes afflict those who care for
them, chiefly attacking the hands and forearms. The treatment is that of similar con­
ditions just described.

Other parasites which attack the human skin for nourishment are the mosquito
(culex anxifer), gnat (culex pipiens), and certain kinds of flies and other insects, and
give rise to erythematous and urticarial lesions, which vary considerably in different
individuals, in some having but little effect, in others quite pronounced irritation. This
may, and usually does, subside quickly, although exceptionally the lesions last one to
several days. In addition to these insects are to be mentioned those which sometimes
attack the skin to inflict injury or in self-defence, such as bees, wasps, spiders, ants,
caterpillars, etc With some of these, especially the bees and wasps, if the stings
are numerous, the effects may be quite serious, in extreme instances death having
resulted. The lesions vary, but are chiefly urticarial in appearance. Some species
of spiders can also produce alarming consequences, a poisoned wound developing
at the point of attack, and followed by systemic symptoms. For obvious reasons the
exposed parts are those attacked, and this fact is of some value in the diagnosis. The
central punctum in these lesions, together with the parts involved and history of ex­
posure, are generally sufficient to prevent error.

1188

PARASITIC AFFECTIONS

Treatment is with the various applications already named. Spirits of camphor,
weakened ammonia water, and menthol preparations are most efficient in relieving the
sting. A 2 or 3 per cent, solution of menthol, oil of eucalyptus, or tar oil is variously
used for protection where these parasites are numerous and troublesome. For wasp
or bee stings common earth or clay made into a paste with water and applied is a well-
known and efficient application.

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