Brief Answer:
Causes of hair fall

Detailed Answer:
Hello and welcome to ask a doctor service. I have gone through your query and noted your concern.

Hair fall can be of several types. Two most common types include Telogen effluvium and Androgenetic Alopecia. Telogen effluvium can be precipitated by infections e.g a febrile illness lasting several days like dengue, malaria, jaundice or significant weight loss, after surgery, post delivery and also by certain medication like antiepileptic (sodium valproate). Certain conditions like thyroid dysfunction, nutritional issues like iron deficiency, vitamin D and vitamin B 12 deficiency can also have increased hair shedding.
Androgenetic alopecia on the other hand is a patterned hair loss, most obvious in males and manifests as thinning and hair loss from the frontal and vertex part of the scalp as well as a receding M shaped anterior hair line in males.
Apart from that Seborrheic dermatitis, psoriasis, alopecia areata, scalp discoid lupus and lichen planus also lead to hair loss and can be easily distinguished on clinical examination.

Hope I have answered your query. Let me know if you need any more assistance.

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Brief Answer:
Regarding hair loss

Detailed Answer:
Hi.
Weight loss that is significant i.e 10% or more of total body weight which is usually secondary to an illness/ surgery or thyroid dysfunction or an eating disorder like anorexia nervosa is associated with hair loss. In that case identifying the underlying cause and taking specific steps to counter it is usually sufficient.
Take care

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