What is onychomycosis? I want the most authoritative explanation, not casual, but very written! Come on, everybody, 3Q.

Onychomycosis is a common name for an infectious disease that occurs on human nails. It is caused by a large class of microbial infections called pathogenic fungi. Onychomycosis begins at the distal end, lateral margin or nail fold. It is characterized by abnormal color and shape of nails, mostly gray and dull. The deck is obviously thickened and the surface is uneven. Its quality is loose and broken, and keratin and debris are often deposited under nails. The clinical manifestation of 10 of onychomycosis is: 1. Turbidity: the deck is opaque, turbid or dirty, losing its luster; 2. Hypertrophy: keratin accumulation under nails; 3. The surface of the nail is uneven: the accumulation of keratin under the nail leads to deck damage; 4. Nail separation: the thickened cutin falls off, resulting in the separation of the deck from the nail bed; 5. discoloration: the diseased nail is white, yellow, gray, brown or even black; 6. Deck atrophy: After being infected by fungi, the deck becomes thinner and smaller; 7. Deck falling off: the deck is completely destroyed and only a small amount remains on the nail bed; 8. Deck inclination: the cutin under the nail falls off, and only the root of the deck is connected with the nail bed; 9. Hook nail: the diseased nail is too long and bends to the palmoplantar side; 10. paronychia: the root and nail groove of the diseased nail are red and swollen, which is generally caused by candida infection. The types of onychomycosis are 1, and the proximal onychomycosis is rare, mostly secondary to paronychia. At first, the deck turned white near the nail fold (that is, near the center of the deck), and then gradually expanded into onychomycosis, and finally some decks were missing. This type of onychomycosis is only caused by Trichophyton rubrum and Trichophyton roseum. 2. Distal onychomycosis: At first, irregular white spots appeared on the deck surface of the distal nail (side edge), then turned into dark gray spots, and gradually turned yellow-brown until black. Soon, the deck deteriorated, keratin debris accumulated under the nails and the nail bed became thicker. Finally, the deck shrinks. Occasionally bleeding. This type is usually caused by red, gypsum-like or flocculent skin fungi. 3. White superficial onychomycosis: common in toenails. White spots or white patches with a diameter of 65438±0mm appear on the deck surface, and the diseased nail is fragile and scraped off. This type is only caused by Trichophyton Gypsophila or mycotic fungi, Fusarium and Aspergillus. 4. onychomycosis: that's not true. It is often the result of the final development of the above types. It is characterized by the loss of luster, deterioration, thickening or fragmentation of the whole nail, and the abnormal thickening of the nail bed after falling off. 5. Chronic cutaneous candidal onychomycosis A (or true candidal onychomycosis): characterized by deterioration, swelling, crispness and warts on the surface of the whole nail. Uneven. 6. Chronic onychomycosis: manifested as lateral nail fold and proximal nail fold, and the epidermal protective film degenerated or turned brown. The most important feature is the presence of onychomycosis, swelling of periungual folds without excessive keratinization, a small amount of exudate but never pus. This type is also caused by candida. 7. Fungal onychomycosis: manifested as beriberi.