Postpartum Hives · What Are They, Causes, Symptoms, and More

Postpartum hives, also known as postpartum urticaria, refers to the development of an itchy rash during the postpartum period, which is the time after birth where the physiologic changes associated with pregnancy return to baseline. This period is generally considered to last between 6 and 12 weeks after childbirth, even though some organ systems may take longer to return to the nonpregnant state. 

Like other forms of urticaria, postpartum hives result from the activation and degranulation of mast cells, which are immune cells that contain granules with proinflammatory molecules, like histamine. Once released, histamine stimulates sensory nerve endings on the skin, leading to pain and itching. In addition, it causes local inflammation and vasodilation. Blood vessel permeability also increases, which allows more fluid to leak out from blood vessels and into the space between cells, thereby causing swelling and redness. 

Although there is a wide range of causes that can lead to urticaria, no specific trigger can be identified in most individuals. Common causes of postpartum hives include infections; allergic reactions to medications, foods, or insect stings and bites; non-allergic adverse reactions to medications (e.g., nonsteroidal anti-inflammatory drugs, or NSAIDs); stress; and lack of sleep. In individuals who have never experienced urticaria, postpartum hives may result from the sudden hormonal changes involving estrogen and progesterone occurring during the postpartum period and their influence on the immune system. 

Signs and symptoms of postpartum hives include a postpartum rash consisting of well-defined wheals that can look like flat or slightly raised bumps. In individuals with light skin tones, wheals can appear red in color; whereas in people with darker skin tones, lesions may be skin-colored, slightly darker, or slightly lighter than their usual skin tone. These lesions typically blanch with pressure, are extremely itchy, and can appear anywhere in the body. The key feature of hives is that lesions come and go very rapidly, meaning one might appear on the leg as another disappears from the arm.

In addition to urticaria, individuals who experience postpartum hives might also develop angioedema, which is swelling deeper in the skin. Angioedema can appear almost anywhere on the skin; but it is most common on the face, especially around the eyes or nose. Unlike hives, angioedema does not cause intense itching but can cause tenderness and burning. In rare situations, urticaria or angioedema can worsen and cause anaphylaxis, a severe allergic reaction that affects multiple organ systems and can be life-threatening. 

Diagnosis of postpartum hives is based on the history and physical examination of the individual’s skin. In some cases, allergy tests may be performed to identify a trigger so that it can be avoided in the future. Allergy tests may involve in vivo prick tests where several allergens are pricked into the skin to monitor for an allergic reaction. Alternatively, blood tests that look for IgE antibodies against specific allergens, such as foods, insect venoms, pollen, latex, or antibiotics, may be done to determine specific triggers. 

Medical treatment for postpartum hives is generally not necessary as it usually resolves on its own within a few days. During this time, home remedies (e.g. cooling moisturizers, taking a lukewarm bath, applying wet compresses on the affected area, wearing loose clothing, etc.) can help improve the itching and soothe the skin. Topical steroid creams may also be used to reduce inflammation. In addition, oral antihistamines (e.g. loratadine, desloratadine, cetirizine) may be prescribed to block the release of histamine and reduce itching and swelling. In severe cases, oral or injectable corticosteroids may be prescribed. In cases of anaphylaxis, treatment generally involves epinephrine, most often given intramuscularly.  

Postpartum hives is a skin rash that develops after pregnancy consisting of skin-colored, slightly raised, itchy bumps, which can cause a burning or stinging sensation. Lesions are frequently caused by allergic reactions; however, no specific cause is found in many cases. Treatment for postpartum hives typically involves identifying and avoiding triggers as well as taking medications like antihistamines to relieve one’s symptoms.