Dreadlocks are only unhealthy if the person doesn't care for them properly.
Often, they are able to begin the hairstyle at home but don't research how to maintain it once it's finished. Yet, if the person properly washes, dries, and cares for their hair, it will be healthy.
One of the most common issues with dreadlocks is the development of mildew due to how difficult it is to dry thick dreads.
This issue can be fixed by rinsing your hair in vinegar, tea tree, and grapefruit seed extract.