Otomycosis is a common disease, accounting for 15-20% of ear infections, and patients are often accompanied by symptoms of aural ringworm. Ear fungal disease occurs mostly in warm and humid tropical and subtropical regions. The fungi that cause auricular ringworm are mainly dermatophytes such as Trichophyton rubrum, Trichophyton rubrum and woolly microsporum. The specific causes of auricular ringworm are as follows: 1. Pathogenesis The majority of pathogenic fungi that cause infections of the external ear canal are Aspergillus fumigatus and Aspergillus niger. Among them, Aspergillus niger accounts for more than 90%. Others are Candida, Ken mold, plow mold, column top spores, short broom mold, root mold, common head mold, etc., mostly from the drift of spores in the air. 80% to 90% of external otitis can be found in a variety of bacteria, such as Pseudomonas, Aspergillus, micrococcus, Streptococcus, Escherichia coli and rod-shaped bacilli, etc., when coexisting with fungi. It can aggravate the fungal infection. Local pre-existing skin lesions such as eczema of the external auditory canal, psoriasis, seborrheic dermatitis, etc. as well as local humidity, damage to the external auditory canal such as ear digging and long-term local use of antibiotics and corticosteroids are important triggering factors. 2.Pathogenesis The fungi that cause auricular infections are mainly dermatophytes such as Trichophyton rubrum, Trichophyton rubrum and woolly microsporum. It originates from the direct spread of ringworm on the head and face or from direct or indirect contact transmission of ringworm of the hands and feet, body and nails, etc. This type of infection is also called tinea capitis. The vast majority of pathogens that cause infections of the external ear canal are Aspergillus fumigatus and Aspergillus niger. Among them, Aspergillus niger accounts for more than 90%.