A male patient presents with patchy loss of hair on scalp, eyebrows and beard. He also gives history of rapid graying of hair in a few areas. The likely diagnosis is –
Information provided in this question are -


Patchy hair loss (focal alopecia)
Hair loss on scalp, eyebrows and beard
Histor of rapid graying of hair


All suggest the diagnosis of Alopecia areata -


In Alopecia areata, hair loss is patchy and well circumcirbed.
Alopecia areata most commonly involves scalp but any hair bearing skin e.g., beard, eyebrows, and eye lashes can be involved.
The characteristic feature of alopecia areata is sparing of grey/white (non-pigmented) hair and preferential involvement of block/brown (pigmented) hair. If alopecia progress rapidly, it appears as rapid greying of hair as black hair are shed and grey hair are spared → Going gray/white overnight phenomenon.
Alopecia areata
Anagen effluvium
Telogen effluvium
Androgenic alopecia