RINGWORM

Synonyms.—Tinea, trichophytina; Trichophytosis; Microsporosis; Dermatomycosis
trichophytina; Fr., Trichophytie; Ger., Herpes tonsurans; Scherende Flechte.

Until somewhat recently ringworm in all its types and in all situa­
tions was thought to be due to one fungus—the trichophyton. And
yet the admirable work of Sabouraud, independently pursued but a
few years back, and by which the plurality of the fungi causing this
malady was established, was, as this distinguished investigator sub­
sequently ascertained and generously pointed out, practically an elab-

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oration of what Gruby had indicated fifty years previously, and the
significance and brilliancy of whose discovery during all this interim
had remained not only unappreciated, but unrecognized.¹ The term
“porrigo decalvans” which he applied to the scalp disease caused by
the small-spored fungus—the microsporon Audouini—previously em­
ployed by Bateman to designate the malady now known as alopecia
areata, led to the erroneous belief that Gruby had this latter affection
in view, and hence his supposed fungus, always looked for in vain by
others in alopecia areata, was soon considered purely mythic. Sa-
bouraud’s brilliant investigations, however, have placed Gruby’s work
in an entirely different light. One of Gruby’s fungi was independently
discovered by Malmsten in 1844, and denominated by him trichophyton
tonsurans. The common belief was that this fungus was one of the com­
mon molds, but Thin and, since, others have shown that it is a specific
fungus. The trichophyton was gradually accepted by most dermatolo­
gists as the etiologic factor in all ringworm cases, and this view continued
to be held until the result of Sabouraud’s studies was announced. Sa-
bouraud, who has done so much in the investigations of the fungi, based
his earlier classification upon the size of the fungus elements, their rela­
tions to the hair-shaft and root, and their resistance to potassium hydrate
solution. His classification then consisted of two main divisions: (1)
the small-spore fungus, or microsporon; (2) the large-spore fungus, or
megalosporon, or trichophyton. He further divided the trichophyton
or megalosporon class into two varieties: (1) megalosporon endothrix,
or trichophyton endothrix, commonly referred to as “endothrix,” in
which the fungus is found inside of the hair-shaft; (2) megalosporon ecto-
thrix, or trichophyton ectothrix, commonly referred to as “ectothrix,”
in which the fungus is found outside and chiefly on the surface of the
hair-shaft; as not infrequently in this latter variety the fungus is found
also in the hair, especially in the cortical portion, it is more recently
spoken of as “endo-ectothrix.” The megalosporon endothrix, or tricho-
phyton endothrix, was further divided into two subspecies: (a) resistant
variety and (b) fragile variety; the former practically unaffected by
potassium hydrate solution, and the latter more or less disintegrated by
it. The megalosporon ectothrix, or trichophyton ectothrix, had several
or more subvarieties. In the endothrix variety the stage of invasion
of the hair by the fungus is short, so short that it may be easily
missed, but there are certain exceptions, as sometimes this invasion
stage is noted to be prolonged, so that at first this fungus may be mis­
taken for an endo-ectothrix. Sabouraud, therefore, divided the endo-
thrix into two subvarieties, the true endothrix and the neo-endothrix,
the latter comprising those with the long invasion stage. For all practical
purposes the classification distinctions as just outlined seem sufficient
for text­book and teaching.

Later investigations by Sabouraud disclosed the fact that the

¹ Bazin, Recherches sur la nature et le traitement des teignes, Paris, 1853, confirmed
Gruby’s observations; and in 1891 Furthmann and Neebe, “Vier Trichophytonarten,”
Monalshefte, 1891, vol. xiii, p. 477, advocated the plurality of the causative fungi, and
described four varieties.

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1106                          PARASITIC AFFECTIONS

etiologic fungi were in reality in much larger number than had been
originally supposed, and that it was not possible to identify them all by
the differences referred to; moreover, he found that some of the tricho-
phyton ectothrix had small round spores that might be mistaken for the
microsporon variety. These reasons led to the necessity of establishing
other more certain means of individual identification; and the most
convenient for the purpose was the culture, designating each variety of
the fungi by the most striking character or feature of its growth in culture-
flasks; the division into the two main classes remaining, however, the
same. According to these later studies by Sabouraud, more than forty
varieties of these two classes of fungi have been found associated with
ringworm, eleven of the microsporon, and over thirty of the trichophy-
ton; of these, twenty-eight are rarely seen, and of those remaining,
there are only about eleven which occur with sufficient frequency to
be mentioned here; most of the cases, in fact, being found due to
five or six varieties—two of the microsporons and about four of the
trichophytons.¹

The Microsporons.—Ringworm when due to the microsporons
is sometimes designated microsporosis. The microsporon Audouini,
of human origin, is chief of the microsporon or small-spore group, and
is the important etiologic fungus in children; most institutional scalp
epidemics of ringworm are due to this fungus; on the other hand, the
family epidemic is probably more commonly due to the microsporons of
animal origin. The microsporon Audouini is well-known in England,
in our own country, and in France, becoming less so in France as the
neighboring borders of Italy, Spain, and Germany are approached;
scarcely being found at all in these latter countries, nor in Sweden,
Denmark and Austria, and elsewhere. The other three somewhat
important ones of this group are the microsporon felineum and its closely
related species, microsporon lanosum (microsporon canis of Bodin), both
of animal origin, and the microsporon tardum, of human origin; these
three are found to be etiologic in a small proportion of cases in England
and France. In our own and other countries, so far as I am aware, no
investigations bearing upon any of the microsporons except the micro-
sporon Audouini are on record. The microsporons, especially the micro-
sporon lanosum, according to Darier, are occasionally responsible for tinea
circinata. The scalp patches due to the microsporon Audouini (and it is
almost wholly a scalp parasite) are usually of the sluggish, well-defined,
round or oval, scarcely visibly inflammatory type, with fine scales of
a gray slate or ashen color, and with many short hair-stumps. The mi-
crosporons of animal origin present similar sluggish lesions on the scalp
in children, sometimes with slightly perceptible inflammatory signs,
and the patches may extend on to the adjacent non-hairy surface; they
usually show an erythematous areola. In children and adults they are
the cause of some cases of tinea circinata and occasional cases of tinea of

¹ See Sabouraud’s classic work, Les Teignes, the most complete and exhaustive
yet published on the subjects of ringworm and favus, and rich in illustrations. Jack-
son and McMurtry’s book on Diseases of the Hair, 1912, presents Sabouraud’s views
on the subject somewhat at length.

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the bearded parts, although in this last region it is now generally thought
that the microid variety of trichophyton ectothrix may have been mis­
taken for the microsporon.

The Trichophytons.—Ringworm when due to these fungi is some­
times designated trichophytosis. The most important endothrix tricho-
phytons, designated according to Sabouraud’s new naming by a culture
characteristic, are: the trichophyton crateriforme (endothrix, resistant),
trichophyton acuminatum (endothrix, fragile), trichophyton violaceum
(endothrix, resistant), and the trichophyton cerebriforme (endothrix (neo-
endothrix), resistant). These endothrix trichophytons are believed to
be of human origin; they seldom provoke active inflammatory symptoms;
they, especially the first three named, are responsible for almost all the
cases of trichophytosis of the scalp, the lesions, as a rule, being small;
they are usually the etiologic fungi in the disseminated and black-dot
varieties; to this group also, especially the last three, are due some cases
of ringworm of the glabrous skin and of the beard, and to the trichophy-
ton acuminatum and trichophyton violaceum, almost all nail cases. Beard
cases are, however, doubtless due most frequently to the trichophyton
cerebriforme, this variety also attacking the glabrous skin and scalp;
on the glabrous skin it frequently gives rise to erythematous patches,
sometimes beset with vesicopustular lesions, and often impetiginous
crusts; on the bearded regions it may present similar conditions, with
small follicular abscesses also; on the scalp patches due to this fungus
are usually rounded, faintly erythematous, also slightly elevated, cov­
ered with yellowish-gray scales, beneath which broken, bent, and twisted
hairs and sometimes stumps are seen. In many cases of trichophyton
ringworm of the scalp the hairs of the patch are not affected so generally
as in microsporon cases, so that in children with long hair the disease
is often overlooked or mistaken for a seborrheic condition. The ecto-
thrix (endo-ectothrix) trichophytons are divided into two classes, those
with small spores and those with large spores—the microid class and the
megaspore class. The ectothrix trichophytons are believed to be, either
directly or indirectly, of animal origin. They almost always provoke
considerable inflammatory reaction, and are usually responsible for many
cases of kerion and for kerion-like lesions. on the scalp and bearded
regions; the neighboring cervical lymphatic glands may become swollen.
Of the microid trichophytons the trichophyton asteroides is the most im­
portant, the lesions from which, usually first erythematous, develop into
follicular, pustular, and kerion formations. Of the megaspore ectothrix
trichophytons those most frequently encountered, although rather rare,
are the trichophyton rosaceum and the trichophyton ochraceum. The
former is usually responsible on the glabrous skin for the segmental
and incomplete circled reddish lesions; on the bearded regions the lesions
due to this fungus are generally small and somewhat disseminated, the
hair is apt to be broken off short and each hair or hair-stump surrounded
at and slightly within the follicular mouth by a minute keratotic dry
scaly cone, presenting a rough resemblance to keratosis pilaris. The
other of this group, the trichophyton ochraceum, may provoke on the
glabrous skin or bearded parts erythematous scaly circles or round

1108

PARASITIC AFFECTIONS

patches, which may become vesicular, pustular, nodular, or kerion-like;
it is met with most frequently in those who have to do with cattle.

It has been found (Castellani, Pernet, Sabouraud, Whitfield) that
the fungus, epidermophyton inguinale,¹ of eczema marginatum (tinea
cruris) is in many ways distinct from the ordinary ringworm fungi. It
had always been supposed to be one of the usual ringworm trichophytons,
but unlike any other species of this class—in which, however, Sabouraud
places it—it never attacks the hair. It is also the pathogenic fungus in
some cases of eczematoid and vesicular and vesicobullous eruptions on
the hands and feet; this fungus is thought to be of human origin. Other
investigators, among whom are Jamieson, Adamson, Colcott Fox and
Blaxall, Unna, C. J. White, Malcolm Morris, Castellani, Whitefield, and
others, have all added to our knowledge of these pathogenic fungi,
and practically accept Sabouraud’s conclusions. Rosenbach, Krösing,
Ullman, Waelsch, Leslie Roberts, Pelegatti, Ducrey and Reale, and others,
whose studies and observations have also contributed to our knowledge,
did not wholly agree with Sabouraud’s original divisions of the fungi, or
with his views that each fungus tends to produce always a special clinical
type of disease, but one can, I think, say that to­day Sabouraud’s bril­
liant work and conclusions rightly hold sway.²

The features, character, and behavior of ringworm vary consider-

¹  Castellani, Brit. Jour. Derm., 1910, p. 149, believes that so far three varieties of the
epidermophyton have been identified: (1) Epidermophyton cruris (Castellani, 1905),
synonymous with epidermophyton inguinale (Sabouraud, 1907), trichophyton cruris
(Castellani, 1905), and trichophyton Castellani (Brooke, 1908); (2) epidermophyton
Perneti (Castellani, 1907); (3) epidermophyton rubrum (Castellani, 1910), synony­
mous with trichophyton rubrum (Castellani), and epidermophyton purpureum (Bang,
1910).

² The reader desiring to pursue further the investigations and mycology of the ring­
worm fungi is referred to the following valuable publications and papers: Sabouraud,
“Contribution a l’étude de la trichophytie humaine,” Annales, 1892, p. 1061; and his
later and more complete publication, Les trichophyties humaines, Paris, 1894; Rosen-
bach, “Ueber die tieferen eiternden Schimmel-erkrankungen der Haut und deren
Ursache,” Wiesbaden, 1894; Leslie Roberts, “The Present Position of the Question of
the Vegetable Hair Parasites,” Brit. Med. Jour., 1894, ii, p. 685; and “The Physiology
of the Tricophytons,” Jour. Pathol. and Bacteriol., 1895-96, vol. iii, p. 300; Adamson,
“Observations on the Parasites of Ringworm,” Brit. Jour. Derm., 1895, pp. 201 and 237;
Colcott Fox and Blaxall, “An Inquiry into the Plurality of Fungi Causing Ringworm in
Human Beings as Met with in London,” ibid., 1896, pp. 242, 291, 337, and 377; and
“Some Remarks on Ringworm,” Brit. Med. Jour., 1899, ii, p. 1529; Bodin, “Des teignes
tondantes du cheval et leur inoculations humaines,” These de Paris, 1896; Aldersmith,
Ringworm and Alopecia Areata, fourth ed., London, 1897; Malcolm Morris, Ring­
worm in the Light of Recent Research, London, 1898; Chas. J. White, “Ringworm as
it Exists in Boston,” Jour. Cutan. Dis., 1899, p. 1; Bodin and Almy, “Le microsporum
du chien,” Receuil de méd. vétérinaire, 1897, p. 161; Suis and Suffran, “Note prelimi-
naire sur le microsporum lanosum du chien,” Annales, 1908, p. 151; Sabouraud, “Iden­
tification du microsporum lanosum (Sabouraud, 1907) au microsporum caninum (Bodin
and Almy, 1897”), Annales, 1908, p. 153; Sabouraud, “Nouvelles recherches sur les
microsporums,” Annales, 1907, pp. 163, 225, 236, and 369 (with review, references, nu­
merous text cuts, and 2 plates—cultures); Sabouraud, Suis, and Suffran, “Fréquence du
microsporum caninum ou lanosum chez le chien et chez l’homme,” Annales, 1908, p. 321
(3 case illustrations (dogs), 15 case recitals (dogs), and cultures with review of the sub­
ject and references); and Sabouraud, “Les trichophytons faviformes,” ibid., 1908, p. 609
(with plate showing cultures, several illustrations, and pertinent references); Colcott
Fox, “A Further Contribution to the Study of the Endothrix Trichophyta Flora in
London, Illustrated by a Collection of Cultures and Photographs,” Brit. Jour. Derm.,
1909, p. 271; Favera, “Sur l’état des trichophyties de la Province de Parme (Italie),”
Annales, 1909, p. 433 (with review and references); and Sabouraud’s Les Teignes.

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ably according to the part involved, whether it be the general, non-
hairy surface, the genitocrural region, the scalp, or the bearded region.
In a measure the anatomic conditions and physical peculiarities of these
various regions are responsible for the difference in the clinical pictures,
although in the light of recent research it is not unlikely that they are
also to some extent to be attributed to the special fungus which may be
etiologically involved. The symptoms and diagnostic characters can
best be described under the several regional headings.

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