The Shulhan Aruch (Orah Haim 551) cites three views regarding the consumption of meat and wine during the period before Tisha B’Ab. The first opinion is that meat and wine are forbidden only during the week of Tisha B’Ab, from after the Shabbat preceding Tisha B’Ab until after the fast. According to the second view, meat and wine are forbidden already from Rosh Hodesh Ab, whereas the third position forbids meat and wine throughout the three-week period from Shiba Asar Be’Tammuz through Tisha B’Ab.
The accepted custom in our community follows the second view cited by the Shulhan Aruch, forbidding meat and wine during the Nine Days, from Rosh Hodesh Ab through Tisha B’Ab. However, whereas the Ashkenazim refrain from wine and meat already on Rosh Hodesh Ab, the custom among the Sepharadim is to allow meat and wine on Rosh Hodesh Ab, and to begin observing the prohibition only after Rosh Hodesh Ab. This custom is codified by Rav Yaakov Haim Sofer (Baghdad-Israel, 1870-1939), in his Kaf Ha’haim (126). The Kaf Ha’haim also mentions, however (in 122), that if a person recites Arbit before sundown on Rosh Hodesh Ab, then he may no longer eat meat or drink wine, even before sundown. Since he already recited Arbit, the prohibitions of meat and wine take effect, even though the sun had not set. Thus, for example, if on Rosh Hodesh Ab a person recites Arbit at 7:15pm, he may no longer eat meat or drink wine, even though the sun does not set for another hour.
If a person has a milk allergy and cannot digest dairy foods, and he thus has difficulty finding foods to eat during the Nine Days when meat is forbidden (such as if, for whatever reason, he cannot eat fish), then he should consult his Rabbi for guidance. The Kaf Ha’haim (146) writes that under such circumstances there is room to allow eating poultry, since there were no bird sacrifices in the Bet Ha’mikdash that were eaten, and the status of poultry during the Nine Days is thus more lenient than that of beef. A person who cannot eat dairy foods should therefore consult with a Rabbi to determine whether his condition allows him to eat chicken. Likewise, if a person must eat meat for medical reasons, as directed by a physician, then he should consult with a Rabbi to determine whether he may eat meat. The Kaf Ha’haim (148; listen to audio recording for precise citation) writes that the Sages did not apply this prohibition in situations of illness, and thus if one’s doctor instructs that he must eat meat for health purposes, he may do so. In all such situations, however, a Rabbi must be consulted for guidance.
Summary: The custom of the Sepharadim is to refrain from meat and wine from the second day of Ab through Tisha B’Ab. If a person needs to eat meat for medical reasons, or has difficulty finding foods to eat, such as if he has an allergy to dairy foods, he should consult with a Rabbi for guidance.