Horizontal hooks on toenails may be caused by external forces, malnutrition, onychomycosis, or other diseases.
1. External force: toenails are subjected to external force, such as trauma leading to nail plate damage, which also affects their growth and may lead to horizontal lines or hooks on the toenails.
2. Malnutrition: Long-term poor living and eating habits, such as partiality, picky eating, excessive dieting to lose weight, etc., leading to insufficient supply of nutrients, which will have an impact on the growth of the toenail, can also lead to toenail malnutrition.
3. Inflammation of the nail: Local inflammatory diseases, such as onychomycosis, may affect the blood circulation around the toenail, which may lead to the appearance of horizontal lines and hooks on the toenail.
4. Other diseases: other diseases, such as nail lichen planus and psoriasis, may lead to abnormal growth of the nail plate and the appearance of horizontal lines and grooves on the toenails.
To summarize, there are more reasons that lead to the appearance of horizontal lines on toenails. If it is caused by external forces, it may recover gradually with time. If you suspect that it is caused by pathological factors, it is recommended to go to the hospital for consultation. After the cause is clarified, further treatment will be carried out.