Certain risk factors dictate the  response of the acne  patient  to  therapy.  Using this information, this  author's department carried out a study on  250 subjects  which demonstrated  that, if a subject has acne and needs  oral therapy, there  is no justification in giving 0.5 g/day -  1.0 g/day is  needed. With patients matched for age, sex, acne severity and site of acne, the group receiving 1 g/day showed significantly greater improvement in their acne:  in females at six months and  in males at two, four and six months.

The side-effects were also investigated; there is no increased incidence of side-effects in those subjects taking 1 g/day compared  with  0.5 g/day.  After  six  months  the oral therapy was discontinued; twelve months later the rate of reoccurrence of the acne was significantly greater in subjects who had received 0.5 g/day.

 

  Therefore, the conclusion  is that a subject needing oral therapy should initially receive 1 g/day tetracycline, given as 500 mg bds.  Although  much of the clinical research was based on  erythromycin - chosen as it is better absorbed than oxytetracycline - no difference in response has been shown between oxytetracycline and erythromycin. Since erythromycin is  more expensive  than tetracycline and  is a more important antibiotic than tetracycline for the internist, it is recommended to all physicians that the first drug  of choice should be tetracycline - 1 g/day.

 

  If, after three months, a patient is no better or worse the oral therapy must be  changed. The change could initially be  to erythromycin if the  patient has  been taking tetracycline.  Alternatives are the  variants of tetracycline  such as doxycycline or minocycline.

 

  There is  no convincing  evidence to indicate  any benefit in giving minocycline or doxycycline initially. These drugs are expensive and put an unnecessary load on health care finances. It is  likely that they are of benefit  in patients who are not  responding well to conventional therapy; limited studies indicate that this is so but such work can  be criticized on the grounds that it does  not adequately define failures in terms of duration of  therapy, dosage and how the therapy was taken.

 

  Trimethoprim is a further alternative but, before embarking upon yet another antibiotic, good  microbiological control is necessary. Therefore,  such a patient should be managed in a hosptial clinic since P. acnes are notoriously difficult to grow and the problem could be complicated by Gram-negative folliculitis.

 

  There is no clinically or scientific proven way to best reduce oral antibiotics. The policy in this department is purely psychological.  Patients are  told gradually to reduce the tablets to zero over a period of a month. Experience dictates this strategy since many patients are horrified if told immediately to stop the therapy that they have been taking for six months. It is important to stress to the patient that a slight flare of the acne is not uncommon within  a few weeks  of discontinuing the tablets but,  provided  they use  the  topical  therapy consistently, most patients will be well  satisfied many months later.  It should be emphasized that in no way will  the  physician  allow the acne  to return  to its pre-antibiotic level of severity and that, if necessary, the physician will reinstitute therapy with oral antibiotics.

 

  In a female, a further possible therapy is a hormonal regimen. In a female who is sexually active  and for whom there are no contraindications a 50 jig oestrogen pill or Dianette could be given for twelve months, plus topical therapy. In  a female over 30 or if there are contraindications to  oestrogen therapy, spironolactone 100 mg bds can be prescribed.

Nonresponders The physician must try to determine why the patient has not responded well. Lack of compliance is unquestionably the commonest reason. This can be checked by noting from the medical records how many prescriptions have been collected. If a patient has been taking antibiotics regularly then Staph, epidermidis should be resistant to  that antibiotic.  If it is not, the  physician should re-address the problem with the patient. Some physicians may have access to Wood's rays. Tetracycline fluoresces yellow; if the skin fluoresces yellow at least it is bearing some tetracycline. A negative test does not, however, necessarily exclude  the patient from having taken the therapy.