Pruritic Urticarial Papules and Plaques of Pregnancy (PUPP), also known as Polymorphic Eruption of Pregnancy (PEP), is the most common dermatosis related to pregnancy. It is an intensely itchy, hives-like rash that typically appears during the third trimester, though it can occur at any time. PUPP is benign and poses no threat to the health of the mother or the developing baby. This article explains the characteristic symptoms, theories on its origin, and available treatment options.
Identifying the Symptoms and Appearance
The rash usually begins with small, raised, pimple-like bumps, known as papules, which resemble hives. These lesions are intensely itchy (pruritus), which is often the primary complaint. The papules frequently cluster together to form larger, swollen, and reddened areas called plaques.
The rash commonly starts on the abdomen, often within existing stretch marks (striae). It can then spread outward to the thighs, buttocks, breasts, and arms. A key diagnostic clue is that the rash almost never affects the area immediately surrounding the belly button (umbilicus). It also rarely spreads to the face, palms, or soles of the feet. In lighter skin tones, the lesions may appear pink or red, sometimes with a pale, white halo surrounding the bumps.
Understanding the Causes and Risk Factors
The precise mechanism that triggers PUPP remains uncertain, but current theories focus on two main possibilities. One hypothesis centers on the mechanical stretching of the skin. Rapid abdominal expansion, especially in late pregnancy, may damage connective tissue, leading to an inflammatory reaction that manifests as the rash.
A second theory involves a potential immunological response to the fetus. Fetal cells or antigens may migrate into the mother’s bloodstream and deposit in the skin, triggering an immune reaction. This is supported by the observation that PUPP occurs twice as often in women carrying a male fetus.
PUPP is most frequently observed in first-time pregnancies. Carrying multiples, such as twins or triplets, substantially increases the likelihood due to the greater degree of skin distension. Other risk factors include excessive or rapid weight gain and a larger-than-average fundal measurement.
Treatment and Management Strategies
The primary goal of managing PUPP is to alleviate the intense itching, as the rash typically resolves on its own after delivery. Treatment begins with comfort measures and topical applications. Simple remedies include taking cool oatmeal or baking soda baths to soothe the irritated skin. Applying a cool, wet compress can also provide temporary relief from the burning sensation.
Topical Treatments
Healthcare providers often recommend topical corticosteroids applied directly to the rash. For mild cases, a low-potency topical steroid cream may be sufficient. If symptoms are more widespread or severe, a medium-to-high potency topical corticosteroid may be prescribed to reduce inflammation.
Oral Medications
Oral medications may be used to control systemic symptoms. Non-drowsy oral antihistamines help reduce generalized itching, especially when sleep is affected. For the most severe cases, where pruritus significantly impacts daily life, a short course of oral corticosteroids may be prescribed. Always consult a healthcare provider before initiating any treatment during pregnancy.
Safety for Mother and Baby, and Postpartum Outlook
PUPP is a benign condition that presents no health risks to the mother or the developing fetus. The rash does not increase the risk of preterm labor, fetal loss, or other complications, nor does it affect the method of delivery. The outlook is excellent once the pregnancy is complete.
The rash usually begins to clear quickly after delivery, typically resolving completely within one to two weeks postpartum. A milder form of the rash may persist for a few weeks longer in some instances. The likelihood of the condition recurring in future pregnancies is low, especially if the subsequent pregnancy is a singleton.