Ob-Gyn Coding Alert

Question: The ob-gyn diagnosed a patient with autoimmune progesterone dermatitis. Which ICD-9 code should I use?
Michigan Subscriber
Answer: This is definitely an autoimmune disorder, so your best code option for the general case is 279.4 (Autoimmune disease, not elsewhere classified).      
You should also code specific skin findings. Possible coding choices include 708.8 (Other specified urticaria [includes chronic urticaria and recurrent periodic urticaria]), 695.1 (Erythema multiforme), 695.89 (Other specified erythematous conditions; other) and 702.8 (Other specified dermatoses).
On the other hand, if your physician does not document that this condition is not incidental to the pregnancy or is not complicating the pregnancy, the management of the mother or the management of the fetus, you will have to use an obstetric diagnosis code as the first listed diagnosis. In that case, you should report 648.93 (Other current conditions classifiable elsewhere, but complicating pregnancy; antepartum condition or complication), followed by 279.4 (Autoimmune disease, not elsewhere classified) and any of the other diagnoses that apply.              
-- The answers for Reader Questions and You Be the Coder were provided by Melanie Witt, RN, CPC-OGS, MA, an ob-gyn coding expert based in Guadalupita, N.M.