The differential diagnosis will include evaluation for alopecia areata, iron deficiency, hypothyroidism, tinea capitis, traction alopecia, alopecia mucinosa, thallium poisoning, and loose anagen syndrome. In trichotillomania, a hair pull test is negative.A biopsy can be performed and may be helpful; it reveals traumatized hair follicles with perifollicular hemorrhage, fragmented hair in the dermis, empty follicles, and deformed hair shafts. Multiple catagen hairs are typically seen. An alternative technique to biopsy, particularly for children, is to shave a part of the involved area and observe for regrowth of normal hairs. Classification
Trichotillomania is defined as a self-induced and recurrent loss of hair. It includes the criterion of an increasing sense of tension before pulling the hair and gratification or relief when pulling the hair. However, some people with trichotillomania do not endorse the inclusion of "rising tension and subsequent pleasure, gratification, or relief" as part of the criteria because many individuals with trichotillomania may not realize they are pulling their hair, and patients presenting for diagnosis may deny the criteria for tension prior to hair pulling or a sense of gratification after hair is pulled.Trichotillomania may lie on the obsessive-compulsive spectrum, also encompassing obsessive-compulsive disorder (OCD), body dysmorphic disorder (BDD), nail biting (onychophagia) and skin picking (dermatillomania), tic disorders and eating disorders. These conditions may share clinical features, genetic contributions, and possibly treatment response; however, differences between trichotillomania and OCD are present in symptoms, neural function and cognitive profile.
Penile pain refers to pain in the penis, human or otherwise. Common causes
Penile injury
Circumcision
Penile fracture
Priapism
Phimosis
Peyronies disease
Sexually transmitted infections
Chronic prostatitis/chronic pelvic pain syndrome

Cultural references
Priapus, a minor Greek god of fertility, is marked by his oversized, permanent erection, which gave rise to the medical term priapism. Some researchers believe the depiction of Priapus penis referred to a penile disease, and that paintings of Priapus were used to ward off the disease. See also
Genital pain
Vaginal pain
Testicular pain
List of the causes of genital pain


== References ==