Vitiligo koebnerized by eyebrow plucking by threading.

Smoking is without doubt one of the greatest causes of avoidable illness and death in the modern world. Most well known is the relationship between smoking and numerous cancers, cerebrovascular and cardiovascular disease. Smoking and most especially nicotine, are, however, sometimes beneficial in certain diseases, including Parkinson's, Alzheimer's, allergic alveolitis, nausea and vomiting of pregnancy, pre-eclampsia, fibroids, carcinoma of body of uterus, ulcerative colitis, pyoderma gangrenosum, aphthous stomatitis and ulceration, pemphigus, herpes simplex and acne. In the immensely justifiable enthusiasm to discredit this dangerous activity, the mechanisms behind these beneficial effects tend to have been un-discussed or ignored. It is the aim of this paper to spur interest in the reasons for these effects. If the mechanisms are elucidated, therapeutic advances may be possible.