Background. Pathologic hairpulling (HP), skin picking (SP), and nail biting (NB) are repetitive, intentionally performed behaviors that cause noticeable hair loss or substantial physical damage, and result in clinically significant distress or functional impairment. To date, HP, SP, and NB have received little attention in the psychiatric literature despite being widespread behaviors.

Methods. The present article reviews the up-to-date research findings on these three forms of pathologic behavior, highlighting their similarities and differences.

Results. Despite HP, pathologic grooming behaviors have not yet been explicitly included in the diagnostic nomenclature. Phenomenology, triggers, consequences and functionality of HP, SP, and NB are similar, which suggest their joint diagnostic categorization. Sufferers often fail to admit the self-inflicted nature of their physical damage out of shame and embarrassment, which complicates the recognition and differential diagnosis of sufferers. Thus, practitioners need to be particularly attentive to physical signs possibly related to these behavior disorders.

Conclusions. Research suggests that HP, SP, and NB are underrecognized problems that occur on a continuum ranging from mild to severe. Further research is needed, especially regarding the etiology of pathologic HP, SP, and NB, to foster the development of both effective and long-lasting treatments and prevention strategies.