I think Typhoid and hormonal disorders are the internal problems in the body.And repeated use of hard water ,execcive stress,Pollution,Acidic shampoo ,Hair dye or Colour may be other external causes.
Baldness should be cured urgently .You are young so your body will respond early.
Next Steps
Consult directly for Panchkarma,Internal medicines and external application of Hair Pack and Hair Oil.Which is having very good results in many many patients in my 26 years pure Ayurvedic practice.
Health Tips
Eat Coconut, Almonds,Dates.