Mom Allergic to Breastfeeding? Rare but It Happens.

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Only a handful of case reports have shown up in the literature

by
Rachael Robertson,

Enterprise & Investigative Writer, MedPage Today

June 13, 2024

A woman said she developed hives all over her body after breastfeeding her newborn son. The woman, who shared her story on social media, said she went to the doctor after also developing a headache and was told a surprising answer to her symptoms: she had a rare condition called lactation anaphylaxis, meaning she’s allergic to breastfeeding.

Lactation anaphylaxis is extremely rare, said Pamela Berens, MD, an ob/gyn at the McGovern Medical School at UTHealth Houston, and only a handful of case reports have been published since the 1990s. Indeed, a search on PubMed for “lactation anaphylaxis” brings up few results, including a 2019 case report in Cureus and a 2015 case in the Australasian Medical Journal.

“I can’t say I’ve ever seen a case in 30 years of doing lactation,” Berens told MedPage Today. Rather than being an allergy to the breast milk itself, Berens said lactation anaphylaxis is more of “an allergic reaction to some of the changes that happen when you breastfeed,” though “it’s unclear which of those hormones kind of trigger that.”

Zachary Rubin, MD, a pediatric allergist and clinical immunologist who frequently posts online about allergies, responded to the video and concurred that he’d never seen a case of the rare condition either. In his video, Rubin suggested that lactation anaphylaxis may be a result of significant changes in estrogen and progesterone levels immediately postpartum, leading to a non-immunoglobulin E (IgE)-mediated allergy.

Bodies go through drastic changes around the time of delivery, Berens explained, such as the rapid drop in estrogen and progesterone levels that lead to lactation. These hormonal changes could perhaps make someone “a little bit more sensitive to histamine release, which kind of increases your risk for having an anaphylactic reaction,” especially early after delivery.

She said the theory is that these rapid falls in hormones after pregnancy “may cause some destabilization” of mast cells — which are involved in anaphylaxis — causing them to increase. This may make some people more prone to a potentially dramatic allergic response. Still, she said anaphylaxis is treated similarly no matter the root cause.

One patient who had lactation anaphylaxis with her first three children was treated with corticosteroids and antihistamines after the delivery of her fourth child, as described in a 2009 case report in Obstetrics & Gynecology. The patient still developed symptoms each time she breastfed, though the symptoms were less severe. Antihistamines and epinephrine ultimately resolved her symptoms and after a few days she didn’t have a recurrence while breastfeeding.

Rubin noted in his video that within the limited literature, some people were able to continue breastfeeding after taking antihistamines or epinephrine, while others had to stop entirely. The woman on social media fell into the former category, and said that she had an EpiPen and had to take allergy medication in order to breastfeed her son. “If I don’t take my allergy medicine, then I will break out in hives while nursing,” she said.

Berens emphasized that this condition is extremely rare, but “rare things do happen, so listen to your patients.”