[en] Hair loss, also called hair effluvium is often considered as an ancillary complaint. However, this situation is quite common in both genders. It is part of numerous clinical presentations in internal medicine and dermatology. Obviously, any correlation between a biologic abnormality and hair loss does not prove a relationship of causality. In absence of pathogenic diagnosis and causality criteria, chances are low to control adequately hair effluvium by a treatment given by the whims of fate. In addition, the risk and frequency of therapeutic inertia are increased. When the hair loss is not controlled and/or compensated by growth of new hairs, several types of alopecia inexorably develop.