Infiltrative-Suppurative, or Zoophilic, Trichophytosis

This form, which is caused by zooanthropophilic fungi, was previously called deep trichophytosis (trichophytia profunda) because the formation of deep suppurative pustules was thought to be its characteristic feature.

An increase in the infiltrative-suppurative trichophytosis morbidity has been registered recently in many countries. Moreover, the role of T. gypseum is outgrowing that of T. faviforme.

Clinical picture and course. Several clinical forms of infiltrative-suppurative trichophytosis are distinguished.

Infiltrative-suppurative trichophytosis of the scalp. In a disease that takes a characteristic course, large solitary foci of affection form. They are sharply circumscribed, hyperemic, considerably infiltrated, and covered with many purulent, succulent crusts. When these crusts are removed, it may often be seen that the pus is discharged from each follicle separately, though at first glance it seems that the patient has a single large and deep-seated abscess; as a result there is another name for the disease, 'follicular abscess'. The pus discharged from each follicle separately resembles honey secreted from the honeycomb. Hence the third frequently encountered name of the disease, kerion Celci ( Celsus ' honeycomb ). In infiltrative-suppurative trichophytosis of the beard and moustache areas ( sycosis parasitaria ), multiple foci of affection form, which are smaller than those on the scalp but in other clinical symptoms are similar to them.

In zoophilic trichophytosis of the deep form, the infiltrate is very tender to palpation. General symptoms (indisposition, a temperature reaction, headache) and enlargement and tenderness of the regional lymph nodes are frequently encountered. With no treatment applied, the disease resolves in a few months leaving scars or, more often, cicatricial atrophy.

In infiltrative-suppurative trichophytosis of the smooth skin the characteristic lesion is a hyperemic patch, which is strictly demarcated from the surrounding healthy skin, has rounded contours, and is infiltrated and covered with furfuraceous or lamellar scales, there are many follicular pustules and purulent crusts on its surface. The infiltrated patch grows along the periphery to a large size (to a diameter of 5 cm and more) and resolves spontaneously in a few weeks, leaving hyperpigmentation and sometimes cicatricial atrophy. The inflammation and infiltration in zoophilic trichophytosis of the smooth skin, however, just as those in affection of the scalp, may vary in intensity from sharply pronounced (the deep form) to a hardly noticeable superficial form.

Diagnosis. Superficial trichophytosis of the scalp has to be differentiated first if all with microsporosis and favus of the scalp. The decisive factors in the diagnosis of trichophytosis are hairs that have broken off at a low level ('stubs'), a considerable amount of hairs preserved in the foci, no tendency of the foci to merge, and the characteristic localization of the fungal spores inside the hair shaft (endothrix). It should be noted that superficial trichophytosis and microsporosis of the smooth skin share clinical symptoms and microscopic picture in common. The character of the involvement of the hairs (if they are also involved), the medical history (e.g. a sick cat in the family or house), studying the epidemiological situation at the children's establishment, the results of cultural diagnosis, etc. make the diagnosis easier.

The diagnosis of chronic trichophytosis of the scalp is based on the presence of 'dark dots' and atrophic bald areas in the occipital and temporal regions, and the characteristic affection of the nail plates. Foci on the smooth skin are differentiated from erythemo-squamous dermatoses (rubromycosis, psoriasis, etc.).

Trichophytosis unguium is differentiated with rubromycosis, favus, and other diseases of the nails.

Infiltrative-suppurative trichophytosis is differentiated with the infiltrative-suppurative form of microsporosis. The latter is caused by Microsporum lanosum and is relatively rare. In localization of the lesions on the face of men, the disease is differentiated with sycosis vulgaris (staphylococcal), which is usually of a long duration and with no rapidly developing inflammatory phenomena. The follicular character of the lesion and the acute course of the process allow zoophilic trichophytosis to be differentiated from chronic pyoderma and deep mycoses (sporotrichosis, deep blastomycosis, etc.).

Microsporosis

Etiology. The causative agents of microsporosis, like the causative agents of trichophytosis, are subdivided into two groups, the anthropophilic and zooanthropophilic fungi. Microsporum ferrugineum and M. audouini are anthropophilic fungi which parasitize only on the human skin and its appendages. M. lanosum (" furry or cat" microsporum, syn. M. canis, or 'dog' microsporum) is the only zooanthropophilic microsporum found in Ukraine. The difference in the terminology is explained by the fact that the main source of zooanthropophilic microsporosis in Ukraine are kittens and cats, whereas in European countries it is mostly transmitted by dogs.

Epidemiology. Infection with anthropophilic microsporum occurs during direct contact with a sick person or through clothes and articles used in everyday life, which are contaminated with the fungi. M. ferrugineum is the most contagious among all known pathogenic fungi. With the appearance of a sick child in the collective, many children become infected. The zooanthropophilic microsporum (lanosum) is acquired from a person sick with the disease" (a rare occurrence) or directly from sick kittens, cats, and dogs.

Infection may also occur through clothes and articles (toys, pillow-cases, scarfs, hats, etc.) contaminated with the fungus. It has recently been established that cats may be mycocarriers.

Microsporosis mainly attacks children. By puberty the disease may be cured spontaneously. In adults, only the smooth skin is involved. Microsporon does not affect the nail plate as a rule.

Clinical Picture and Course of Microsporosis caused by anthropophilic M. Ferrugineum

Affection of the scalp is marked by the appearance of very many small foci with irregular outlines and unclear boundaries, which resemble the lesions in superficial trichophytosis. Unlike the latter, however, in anthropophilic microsporosis the foci tend to coalesce and form one large focus of affection with polycyclic edges, moderate scaling, and a cyanotic-pink colour. This form of microsporosis is characterized by the localization of the foci in marginal zones: some are on the smooth skin and others on the scalp. Often foci are arranged in the form of iris, i.e. one of the rings (the hyperemic ridge of swelling) seems to be arranged within another, sometimes forming quaint patterns. The regularly found well pronounced follicular hyperkeratosis in the foci of affection on the scalp is a clinical symptom distinguishing the disease from superficial trichophytosis and zoophilic microsporosis of the scalp. A characteristic feature of all forms of microsporosis is that the affected hairs break off long ( 5-8 mm from the skin surface) and that there is a whitish muff at the base of the hair shaft. All the hairs are affected in the focus.

The foci on the smooth skin are well outlined and often produce quaint figures and iris forms. M. ferrugineum often causes isolated affection of the smooth skin without involvement of the scalp in the process but with affection of the downy hair, as a result of which it is difficult to cure a patient.

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