Herpes gestationis, third trimester

This code represents pemphigoid gestationis, a rare, autoimmune blistering skin condition that develops during pregnancy. It is characterized by intensely itchy, hive-like lesions and blisters, specifically when these symptoms manifest during the third trimester.

Apply this code when documentation clearly indicates a diagnosis of pemphigoid gestationis (herpes gestationis) occurring in a pregnant patient who is in her third trimester. Supporting documentation should include physician notes detailing the characteristic rash and blistering, along with the gestational age at onset or presentation.

• Ensure the documentation specifies "third trimester" for accurate code assignment; otherwise, a different trimester-specific code for herpes gestationis may be more appropriate.
• Do not confuse pemphigoid gestationis with herpes simplex virus infection; these are distinct conditions.
• Always sequence this code as a primary diagnosis when it is the reason for the encounter, or as a secondary diagnosis if it is a co-morbidity affecting the pregnancy.