* Hair Follicle Damage: Repeatedly pulling out hair (a condition called trichotillomania) can damage the hair follicles over time. Scar tissue may form, making it impossible for the hair to regrow.
* Alopecia: Certain types of alopecia (hair loss) can cause permanent hair loss. For example, scarring alopecias (like lichen planopilaris or discoid lupus erythematosus) destroy hair follicles.
* Other Skin Conditions: Skin conditions such as fungal infections, psoriasis, or other inflammatory conditions can affect the scalp and damage hair follicles.
* Medications or Treatments: Some medications (like certain chemotherapy drugs) and treatments (like radiation therapy) can cause permanent hair loss.
* Aging: As we age, hair follicles can shrink and produce thinner, shorter hairs, or stop producing hair altogether.
It's important to see a dermatologist or other healthcare professional to determine the exact cause and explore potential treatment options. They can examine your scalp, ask about your medical history, and possibly perform a biopsy to diagnose the underlying issue.