first of all, topical applications don't get into the bloodstream much, let alone into the milk...
I have a very strong topical steroid cream that I use as needed and my dr. reassured me of that (what I wrote above)
I found an article online about nipple eczema... now I could see that as very much exposing a baby to the steroid but a study even says: Journal of Human Lactation, 1993, "Potent topical steroids are safe for short-term treatment ... careful use of steroid preparations for 10 days should not present a danger to the infant ... A mild steroid (hydrocortisone) may be applied if symptoms return."
Although every effort should be made to help mothers with smoking cessation, mothers who smoke should be encouraged to breastfeed as breastfeeding may mitigate some of the negative effects of smoking on the health of their infant  . Mothers who continue to smoke should avoid smoking in the presence of the infant and within the home. Alcoholic beverages should be limited as alcohol passes freely into breast milk. Mothers and physicians should refer to Motherisk  for questions about drug safety and breastfeeding. Interruption of breastfeeding is not recommended for physiological jaundice or for breast milk jaundice  , and a search for alternate diagnoses should be undertaken in prolonged or refractory cases. For breast-milk jaundice, the health care provider needs to assess the infant’s latch thoroughly, teach appropriate breastfeeding skills and monitor feeding closely. Referral to a certified lactation consultant should be strongly considered for breastfeeding difficulties.
During conventional pharmacologic dose corticosteroid therapy, ACTH production is inhibited with subsequent suppression of cortisol production by the adrenal cortex. Recovery time for normal HPA activity is variable depending upon the dose and duration of treatment. During this time the patient is vulnerable to any stressful situation. Although it has been shown that there is considerably less adrenal suppression following a single morning dose of prednisolone (10 mg) as opposed to a quarter of that dose administered every six hours, there is evidence that some suppressive effect on adrenal activity may be carried over into the following day when pharmacologic doses are used. Further, it has been shown that a single dose of certain corticosteroids will produce adrenal cortical suppression for two or more days. Other corticoids, including methylprednisolone, hydrocortisone, prednisone, and prednisolone, are considered to be short acting (producing adrenal cortical suppression for 1¼ to 1½ days following a single dose) and thus are recommended for alternate day therapy.