What is it, Risk Factors, and More
Author: Nikol Natalia Armata
Editors: Alyssa Haag, Emily Miao, PharmD
Illustrator: Jillian Dunbar
Copyeditor: David G. Walker
What is PUPPP Rash?
Pruritic Urticarial Papules and Plaques of Pregnancy (PUPPP rash), also known as Polymorphic Eruption of Pregnancy (PEP), refers to a benign, pruritic (i.e., itchy) skin disorder of pregnancy that predominantly occurs over the abdomen but may also extend throughout the body. The rash usually begins with the formation of papules, or small, raised bumps, on the skin that can be up to 1 cm in diameter. The small papules subsequently fuse into larger plaques on the skin that can be larger than 1 cm in diameter.
The PUPPP rash is the most common skin condition that occurs in pregnancy and typically affects primiparous individuals in the third trimester of their pregnancy (i.e., weeks 28 until birth). Most commonly, the rash appears at around 35-36 weeks of pregnancy. Less frequently, the rash may appear a short period of time after the delivery of the baby (i.e., postpartum period).
Is PUPPP rash contagious?
PUPPP during pregnancy rash is not contagious nor does it pose any risk to the mother or fetus.
What causes PUPPP rash?
The exact causes of PUPPP are still not identified; however, various theories have been proposed. The most dominant theories are the ones claiming that the rash develops in areas where the skin is stretched, such as the abdomen: an area of the body which extends dramatically during pregnancy. The increased vascularity and damaged collagen of the skin could trigger an immune inflammatory response, resulting in the PUPPP rash. Notably, in about 90% of the cases, the rash develops near areas with damaged connective tissue (i.e., stretch marks). Hormonal changes that occur during pregnancy may potentially also contribute to the development of the PUPPP rash. High levels of progesterone, for example, have been identified in many individuals with PUPPP rash. Lastly, fetal DNA can also be a triggering factor for the development of PUPPP. There are theories that peripheral deposition of fetal DNA (especially of male fetuses) on the mother’s skin, which occurs particularly during the third trimester, could be associated with PUPPP.The mechanism by which lesions extend to the rest of the body is also unclear. The rash rarely appears in subsequent pregnancies, possibly due to a stronger response of the immune system.
What are the risk factors for PUPPP rash?
The most common risk factor for the development of PUPPP is excessive and rapid weight gain as this can be associated with the development of stretch marks. Similarly, multiple gestations, such as twins or triplets, constitute an additional risk factor as the abdomen tends to increase in size in those pregnancies. Lastly, an individual’s first pregnancy is more likely to develop PUPPP.
What are the signs and symptoms of PUPPP rash?
The most characteristic symptom of PUPPP is that the rash appears to be intensely itchy with small, red (i.e., erythematous), and swollen (i.e, edematous) papules and plaques. The lesions can often conjoin to form larger pruritic plaques often surrounded by a blanched (i.e., pale) halo. PUPPP first presents in stretch marks, especially near the belly button (i.e., umbilicus), and within a few days, can spread to the trunk, extremities (i.e., thighs, and arms), and sometimes the buttocks. The rash is typically painless and does not form blisters.Though widespread, the rash rarely involves the face, palms, or feet. Over time, the rash may progress to develop variable presentations, such as widespread redness (i.e., erythema) and eczematous plaques (i.e., dried and itchy areas). It typically resolves within an average of 4-6 weeks, or within two weeks after delivery, leaving no scars or discoloration of the skin.
How is PUPPP diagnosed?
The diagnosis of PUPPP is based mainly on a detailed physical examination of the entire body in order to assess the skin irritation and review the individual's medical history. Notably, the target-like lesions of PUPPP may also mimic medication reactions. A thorough history review can indicate if new medications were recently initiated. Typically, routine blood tests are within normal ranges. Additional, more specific tests, such as serum analysis or skin biopsies, can be performed to exclude other skin conditions (e.g. pemphigoid gestationis, the infection from herpes during pregnancy). The final diagnosis is often based on exclusion.
How do you get rid of PUPPP rash?
In all cases, the treatment of PUPPP varies according to the individual's symptoms and severity of the rash. The majority of affected individuals achieve satisfactory control with topical steroid creams (e.g., mometasone furoate 0.1%) and oral antihistamines (e.g., diphenhydramine). First- and second-generation antihistamines (e.g., diphenhydramine, chlorpheniramine) are typically safe during pregnancy and can be used as additional therapy to provide relief from pruritus. For more severe irritations, which can disturb the individual's sleep, a short course of oral steroids (eg. prednisone) can be helpful.
Further soothing measures, such as cool baths, frequent application of moisturizing creams, and light cotton clothing offer additional symptomatic relief. Recently, intramuscular injection of autologous blood therapy (i.e., injection of an individual's own blood) has been suggested in the literature as a possible alternative treatment, especially in cases of postpartum PUPPP.
What are the most important facts to know about PUPPP rash?
Pruritic Urticarial Papules and Plaques of Pregnancy (PUPPP rash) is an itchy rash presented during pregnancy. It first presents with the formation of small, red, and swollen papules that may even merge into larger plaques. PUPPP usually develops near stretch marks, especially by the belly button and, within a few days, can spread to the trunk and extremities. Though the underlying causes are not yet known, it has been confirmed that PUPPP is neither contagious nor dangerous for the fetus. The diagnosis of PUPPP is based on exclusion. In order to treat the PUPPP rash, topical steroid creams and oral antihistamines are typically used. In severe cases, a short course of oral steroids can be administered.
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Resources for research and reference
Beckett, M. A., & Goldberg, N. S. Arch Dermatol. (1991). Pruritic urticarial plaques and papules of pregnancy and skin distention. Arch Dermatol, 127(1):125-126. DOI: 10.1001/archderm.1991.01680010137029
Chouk, C., & Litaiem, N. (2021) Pruritic urticarial papules and plaques of pregnancy. In: StatPearls [Internet]. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK539700/Pruritic urticarial papules and plaques of pregnancy. American Osteopathic College of Dermatology. Retrieved from https://www.aocd.org/page/PUPPP