A comparative statistical study of the frequency of asymptomatic ringworm as occurring in the more common cutaneous affections

Abstract

Abstract 1.1. One hundred and eighty-five patients suffering from various skin affections were examined for the presence of ringworm fungi in the interspaces of the feet, both by the extemporaneous method and by culture on Sabouraud's media. 2.2. Of this number, 92 or 49 per cent were proved positive for fungi on microscopic examination and 93 or 51 per cent negative. 3.3. Only in 4 instances or 2 per cent could a positive ringworm growth be obtained on Sabouraud's media. 4.4. Forty-five patients with acne vulgaris were studied. Of this number, 27 or 60 per cent were negative for fungi by the extemporaneous method, while 18 or 40 per cent were positive. Out of the 45, there was only one case which gave a positive ringworm growth on Sabouraud's media. 5.5. Fourteen patients with eczema were studied with the following results: Three or 22 per cent were positive for fungi by the microscopic method and 11 or 78 per cent were negative. All failed to give a ringworm growth on Sabouraud's media.Eight patients with either psoriasis or lichen planus were studied, and of this number 12.5 per cent showed positive microscopic findings and 87.5 negative results. 6.6. Ten patients with seborrheic dermatitis were examined. Of this number 5 or 50 per cent were positive for fungi by microscopic examination and 5 or 50 per cent negative. All failed to yield positive cultures on Sabouraud's media. 7.7. Patients with various forms of dermatitis, scabies or tumors showed about an equal proportion of positive and negative microscopic findings. 8.8. While the general average of positive fungus findings by microscopic examination was 49 per cent for the entire series, the eczema group only yielded 20 per cent positive results, acne vulgaris 40 per cent, but the seborrheic dermatitis group gave 50 per cent positive. Although this series is rather small upon which to base definite conclusions, it would appear that the eczema patients seem to offer the least favorable soil for asymptomatic epidermophytosis and seborrheic dermatitis patients the most favorable environment. 9.9. Statistical study of the frequency of asymptomatic mycosis of the feet is well recognized. However, doubt as to the pathogenicity of the ringworm fungi encountered in this affection still remains. This investigation is an attempt to show that these fungi, through their ability to grow in favorable culture media outside the body probably possess potential powers of assuming the same role in the human skin, when conditions become favorable. Since it was found impractical to fulfill all of Koch's postulates, particularly reinfection of human beings with ringworm fungi, this work was not carried on beyond the attempt to culture on Sabouraud's media. 10.10. An important lesson to be drawn from this paper is the need for a test, cutaneous or otherwise, through which the potential, latent pathogenic powers of the fungi of asymptomatic ringworm fungus infection could be determined. By such a method it would also be possible to reconcile the discrepancies between the cultural and microscopic findings of asymptomatic mycosis.