Sine I gave birth to my little boy 3 years ago both my thumb nails are very britle.(dotn know if this is related) they seem to crack very low down near the base and then it takes months for the crack which will spread across the whole nail to grow out . Once its grown out it happens all over again sometimes a second or third crack will appear before the first one has grown out, this is painful
, but may also be due to certain diseases and conditions. This could be due to injury, long-term use exposure to moisture or nail polish, fungus or yeast infection, thyroid diseases including hyperthyroidism or hypothyroidism, malnutrition, or vitamin deficiency.
Are there other signs or symptoms present? It would be best to have this evaluated further by your doctor for proper diagnosis and management. A complete physical examination and some diagnostics such as blood tests is needed to reach a diagnosis. Nail sample evaluation under the microscope may rule out fungal infection. Treatment usually depends on the underlying cause.