Trichotillomania
Exclamation Mark Hairs
Exclamation mark hairs are short hairs that are thick at the top and thinner as they enter the scalp. These hairs are known to occur in the autoimmune condition alopecia areata but also can occur in trichotillomania (shown this picture), poisoning situations (ie thallium) and have also been reported in dissecting cellulitis.
This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.