Is it safe to use dermikelp itch lotion during breastfeeding?

Likely: There are no studies I know of for this regional herbal lotion. However, as long as it is not applied to the skin surfaces used for/during breastfeeding there is little chance it would affect baby. To do so the components of any lotion would need to penetrate the skin deep enough to enter the blood & them be added to the milk. This does not occur in these preparations.