Medical mystery: What caused new mother’s severe allergic reaction?

A young woman came to our emergency department with shortness of breath, wheezing, vomiting, and hives. All of these symptoms are consistent with a severe allergic reaction requiring urgent treatment. She was given intravenous medications immediately and placed on oxygen therapy.

Fortunately, she recovered quickly. Once she stabilized, she revealed that it was her third visit to the emergency department for the same symptoms, all in the space of two weeks.

In both of her previous ED visits, she was diagnosed with anaphylaxis — a particularly severe form of allergic reaction — given the same medications and then discharged with a short course of steroids to prevent recurrence.

No allergic trigger had been identified, however. She had not used any new lotions or soaps, tried new foods, or changed laundry detergent or household cleaners, all of which are common triggers that we frequently learn about when we talk to patients with allergic reactions.

During this ED visit, however, the patient noted that prior to this reaction and before each of her two other reactions, she had just breastfed her newborn. She reported developing a slight itchy rash every time she breastfed, with the most profound reactions occurring once her courses of medications were complete.

She joked nervously about being allergic to her new baby. Maybe she wasn’t far off the mark.

The patient was observed in the ED for several more hours with no recurrence of symptoms and discharged with a diagnosis of lactation anaphylaxis.

Lactation anaphylaxis is a very rare condition, but one that must be considered when breastfeeding mothers present with allergy and anaphylaxis.

Lactation anaphylaxis is not fully understood, but the condition is believed to be due to the abrupt hormonal changes women experience after giving birth. These changes can cause instability in the cells and immune mediators, which lead to an allergic response. During the act of breastfeeding, a surge in the hormone prolactin is believed to trigger an anaphylactic response.

The diagnosis of lactation anaphylaxis is primarily made through a clinical examination, although testing with an allergy specialist may be helpful for confirmation. Anaphylaxis is a life-threatening condition that must be identified early and treated appropriately with medications including epinephrine, antihistamines, steroids, and IV fluids. Once patients are stabilized, a thorough history can help to identify possible triggers and prevent future episodes.

Some women may need to stop breastfeeding to get relief. In some cases, patients can try using allergy medication prior to breastfeeding, and that will resolve the issue.

Ultimately, our patient decided to transition to formula feeding. At a three-month follow-up appointment, she reported no recurrence of anaphylaxis since stopping breastfeeding.

Rick Pescatore, D.O., is director of clinical research in the department of emergency medicine at Crozer-Keystone Health System and may be contacted on Twitter @Rick_Pescatore. Sundeep Jassal, D.O., is an emergency medicine resident at Crozer-Chester Medical Center.