Not to stand naked before a candle:[1]

One is not to stand before a candle naked as all that stand naked before a candle become crippled. [Nevertheless, in the Poskim we find a number of disclaimers towards this warning: Some[2] explain that this danger only applies when standing still in front of the candle. It is however permitted to walk by the candle, even if one is unclothed. Others[3] write it only applies when one stands in very close proximity to the candle, and not from a distance, even if he is able to benefit from the light. Others[4] rule that this danger only applies towards adults, and not towards children.]

Shabbos candles:[5] It is customary to cover the children [and certainly adults] so they not be naked in front of the [Shabbos] candles due to it being a belittlement of the Mitzvah [Bizuiy Mitzvah]. [This applies even if one is at a distance from the candles, and even if the child is not standing in front of the candles.[6] This applies even if only the Erva is revealed while the remainder of the body remains covered.[7] Thus, one is not to change a baby’s diaper in the same room as the Shabbos candles. The same applies against doing any belittling matter in front of the candles.[8] The same applies to any other Mitzvah candle such as a Havdala candle, Chanukah candles, and candles of a Shul.[9] It however does not apply to a Yartzite or Yizkor candle that is lit at home.]