Anaphylaxis is a severe, systemic allergic reaction that is caused by the release of histamine from the tissues. Many people are familiar with the perils of anaphylaxis in response to insect stings, nut products, medications and latex. However, most are unaware of the extremely rare case of breastfeeding anaphylaxis (BFA). There have been five cases reported thus far that document the onset, progression and ultimate conclusion of anaphylactic symptoms after the start of breastfeeding. In most of these cases, the women experienced symptoms starting 2 to 3 days post-partum that were typically alleviated upon the cessation of lactation. Thus, each case report came to similar conclusions, that anaphylaxis must be caused by breastfeeding, milk let-down or hormone changes that occur between end-stage gestation and lactogenesis. In addition, many of these women had been taking non-steroidal anti-inflammatory drugs (NSAIDS) to control pain after giving birth, which have been linked to exacerbating anaphylaxis. Thus, the use of NSAIDS is considered to be a secondary contributor to the reaction. Due to the rarity of BFA, very little research has been conducted on the pathogenesis of the reaction. Yet one study showed an increase in the numbers of mast cells in the mammary glands and the uterus during pregnancy. These histamine releasing mast cells are thought to be stabilized by increased progesterone during pregnancy and increased corticosteroid release during labor and delivery. After delivery there is an abrupt hormone shift that allows for lactogenesis to occur. During this shift, the progesterone and steroid levels rapidly decrease, potentially causing the release of histamine, which is likely responsible for the anaphylaxis. While this pathological mechanism is not confirmed, the timing indicates a possible correlation considering that progesterone and cortisol levels diminish after delivery to their lowest point 2 to 3 days postpartum; which is the most common time for the onset of symptoms. In addition, most of the women who had experienced BFA in prior pregnancies had a recurrence in subsequent pregnancies. Thus, for the best protection, women with a history of BFA should begin a regimen of antihistamines and corticosteroids immediately after delivery and should avoid NSAIDs. Also, if anaphylaxis still occurs, the risks and benefits of continued breastfeeding should be evaluated with a physician.
For more information:
http://www.uptodate.com/contents/anaphylaxis-in-pregnant-and-breastfeedi...
http://onlinelibrary.wiley.com/doi/10.1111/j.1398-9995.2010.02486.x/full
References:
1. Rudolph MI, Rojas IG, Penissi AB. Uterine mast cells: a new hypothesis to understand how we are born. Biocell 2004;28:1–11.
2. Marion, DW. Anaphylaxis in pregnant and breastfeeding women. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011.
3. McKinney KK, Scranton SE. A case report of breastfeeding anaphylaxis: successful prophylaxis with oral antihistamines. Allergy 2011; 66:435.
4.Shank JJ, Olney SC, Lin FL, McNamara MF. Recurrent postpartum anaphylaxis with breastfeeding. Obstet Gynecol 2009; 114:415.
