Fungal Skin Infection

Vegetable parasites is a group name of fungi which are pathogenic both to human beings and animals. Fungal diseases are very common. Like most infections, they are prevalent in tropical and subtropical countries. Unless properly treated, they become chronic.

Baer and Sulzburger's work has established that fungus diseases occur only in certain susceptible persons and on certain susceptible areas, Furthermore, the present feeling is that these fungi are only facultative pathogens. Only in the presence of certain adjuvant factors like trauma, maceration, warmth, lack of fresh air and sunlight to a part, previous infection, sensitization and debility, are these fungi facilitated to develop pathogenic lesions. A better understanding of these adjuvant factors will help us to understand why some people develop fungus diseases, and others do not despite living in intimate contact with infectious patients. Hence, importance of the body's basic resistance (in other words "condition of the soil") must be appreciated in comparison with the causative organisms and fungi, on which, undue stress has been laid in the past.

Fungi usually attack keratinized structures like the skin, hair or nails. Only in deep mycoses deeper living structures are invaded. Fungi from animal sources (zoophilic), particularly horses and cattle, usually cause severe inflammatory ringworm and kerions.

In conditions like pityriasis versicolor, invasion of the stratum corneum is very superficial, indeed.

Immunology of Fungal Skin Infection

Body ringworm particularly caused by zoophilic fungi induces delayed sensitivity. It can be demonstrated by intra-dermal reaction to trichophytin.

Diagnosis of fungus affections is usually confirmed by demonstration of fungus in potassium hydroxide preparation and/or culture on Sabouraud's medium. Histopathology is seldom helpful.

Treatment of Fungal Skin Infection

Treatment of fungus disease has been revolutionized in recent years. It consists in:

1. Correction of the underlying facilitating factors enumerated above and increasing the local resistance of the parts by keeping them properly dry; exposure to fresh air, exercise etc.
2. Topical fungicidal agents like Natamycin (P), tolnaftate, miconazole, buclosamide [Jadit (P), quinolor derivatives, econazole, Whitfields' ointment, tincture iodine, tinct, merthiolate, ciclopirox olamine (Loprox-P), gentian violet, Castellani's paint, salicylanilide and copper sulphate; nystatin topically in monilial infections.
3. Systemic griseofulvin in tinea. It has no action on monilial or deeper fungi or pityriasis versicolor. Ketoconazole, Fluconazole and Itraconazole in superficial and deep mycosis. It is also useful in pityriasis versicolor-topically and systemically. Nystatin is effective in systemic moniliasis. Amphotericin-B is effective in disseminated moniliasis and deeper fungus affections like blastomycosis. Stilbamidine is useful in blastomycosis.

Also useful are sulphonamides and penicillin in some cases of actinomycosis. Flucytosine is useful in cryptococcus, candida, torula and cladosporium spp.

The prognosis has improved. Tinea has become curable though deeper fungus affections are still troublesome.