Clinical Reference / Therapeutic Strategies / Pruritic Urticarial Papules and Plaques of Pregnancy

Pruritic Urticarial Papules and Plaques of Pregnancy


Key Points

  • Pruritic urticarial papules and plaques of pregnancy (PUPPP) is a benign and common eruption of pregnancy but can be highly symptomatic.
  • The eruption is generally self-limited and responds well to topical management in most cases.
  • Maternal and fetal outcomes are not affected.

Introduction

 

Pruritic urticarial papules and plaques of pregnancy (PUPPP) is a common disorder of pregnancy with a reported incidence of about 1 in 200 pregnancies. It usually begins in the third trimester, especially in the last month of pregnancy, and typically resolves within a few weeks after delivery. The eruption is more common in primiparous women and rarely recurs with subsequent pregnancies. Postpartum onset is rare but can occur. Most importantly, PUPPP does not affect maternal and fetal outcomes and neonatal skin is not typically affected by this condition

The cause of PUPPP is unknown. Some studies suggest a relationship between increased weight gain and abdominal distention and the development of PUPPP. One theory suggests that rapid weight gain and subsequent stretching of skin and connective tissue leads to exposure of antigens that elicits an inflammatory response. This could explain the tendency for lesions of PUPPP to present within striae, a hallmark of the disorder. Other studies have found evidence of fetal DNA within maternal skin lesions suggesting that the skin lesions develop secondary to an immunologic response to fetal antigens.

Synonyms: polymorphic eruption of pregnancy (some authors prefer this term as it encompasses the various morphologies that can occur with PUPPP).

Initial Evaluation

PUPPP is characterized by the abrupt onset of 1-2 mm, erythematous, edematous papules that often begin on the abdomen but can spread to involve the trunk, buttocks, and proximal extremities. The distal extremities, face, and mucosa are typically spared. Papules often localize to the striae and spare the umbilicus and can be helpful clues for the diagnosis. Lesions are often surrounded by a thin blanched halo. The papules can coalesce into urticarial plaques with overlying pseudovesicles and rarely true vesicles. Targetoid or eczematous- appearing lesions and diffuse erythema may also be seen often later in the disease course. The lesions are highly pruritic.

Skin biopsy is rarely necessary as the diagnosis can often be made clinically. Histopathological findings for PUPPP are largely non-specific and include a perivascular lymphocytic dermal infiltrate with variable eosinophils, neutrophils, and dermal edema. The epidermis is often unaffected, though focal spongiosis, acanthosis, and parakeratosis may be seen.

If pemphigoid gestationis is on the differential diagnosis (early urticarial lesions of pemphigoid gestationis can mimic PUPPP), a skin biopsy and direct immunofluorescence (DIF) should be obtained. DIF in PUPPP is typically negative but rarely can have granular C3, IgM or IgA at the dermoepidermal junction. In contrast, pemphigoid gestationis is characterized by linear C3 at the dermoepidermal junction.

Routine laboratory evaluation is normal in PUPPP. Indirect immunofluorescence, if obtained, is negative. A serum bile acid level should be obtained if intrahepatic cholestasis of pregnancy is a diagnostic consideration and and the level should be normal in PUPPP.

Differential Diagnosis

Allergic contact dermatitis

Urticaria

Drug eruption

Erythema multiforme (if target/targetoid lesions present)

Scabies

Viral exanthem

Other pregnancy dermatoses:

Pemphigoid gestationis (aka herpes gestationis)

  • Typically occurs during second and third trimesters with urticarial lesions and prominent vesicles and bullae
  • Lesions do not localize to striae and do not spare the umbilicus
  • Often recurs with subsequent pregnancies and is associated with low birth weight and prematurity

Intrahepatic cholestasis of pregnancy

  • Typically presents with prurigo nodules and/or excoriations (no primary skin lesions)
  • Risk for prematurity, intrauterine fetal demise, meconium staining
  • Bile acids are elevated, LFTs may also be elevated

Atopic eruption of pregnancy

  • Often presents earlier in pregnancy and more localized to extremities
  • No maternal or fetal risk

Treatment

PUPPP is self-limited and the goal of treatment is symptom relief.

First steps

Topical steroids are first-line. In mild disease, low and medium potency topical steroids are typically adequate. In more severe disease, high potency topical steroids may be necessary. Antihistamines can also be of benefit but pregnant patients should discuss with their obstetrician prior to use. For patients who are breastfeeding, antihistamines should also be used with care and the neonate should be monitored for any signs of sedation.

Subsequent steps

Only rarely are systemic steroids required in this condition. Prescribe the minimum effective dose (initially usually 0.5-1 mg/kg in a single dose each morning) and rapidly taper to the lowest controlling dose.

Pitfalls

  1. The early, urticarial phase of pemphigoid gestationis may resemble PUPPP. Pemphigoid gestationis may be associated with fetal morbidity (see above). A biopsy for direct immunofluorescence may be indicated.
  2. Allergic contact dermatitis, especially to surgical prep, etc., used on the abdomen (especially during cesarean section) can mimic PUPPP. The treatment for these two conditions is similar but the diagnosis of an allergic contact may inform subsequent exposures and procedures.
  3. Scabies and other insect bites are morphologically similar to PUPPP. Look carefully for burrows and take a history of animal exposure.

Clinical Case

Case 1

Initial evaluation

A 32-year-old healthy female who is 36 weeks pregnant presents for a severely itchy, bumpy rash. It started on the abdomen three days ago but now has spread to her upper thighs and buttocks. She denies any new exposures, close contacts with similar rash or itching, pets, or new medications. Her pregnancy has been uncomplicated and she is otherwise feeling well.

On exam she has many 1-2 mm urticarial papules diffusely on her abdomen, especially along the striae and sparing her umbilicus, and on her upper thighs, lower back, flanks and buttocks. The rest of her exam is clear and she has no mucosal involvement, no vesicles, bullae, or burrows, and no interweb space involvement. She denies full body pruritus and is only itchy where she has the rash.

Diagnosis: Pruritic urticarial papules and plaques of pregnancy (PUPPP)

Given that her history and skin findings are highly suggestive of this diagnosis, skin biopsy and laboratory evaluation are not pursued. However, anticipatory guidance is given that if the patient’s symptoms or skin findings worsen significantly or she develops many vesicles or bullae or full body itching, she should seek reevaluation.

Treatment

Given the relatively extensive involvement and severe itching, a high potency topical steroid is prescribed twice a day.

Follow-up evaluation

The rash and itching improve significantly over several days and she does not require antihistamines. The rash resolves completely within 1 week after her delivery. Mother and baby do well.

References

Aronson IK, Bond S, Fiedler VC, et al. (1999). Pruritic urticarial papules and plaques of pregnancy: clinical and immunopathologic observations in 57 patients. J Am Acad Dermatol, 39:933-9.

Holmes RC. (1989). Polymorphic eruption of pregnancy. Semin Dermatol, 8:18-22.

Lehrhoff S, Pomeranz MK. (2013). Specific dermatoses of pregnancy and their treatment. Dermatol Ther, 26(4):274-84.

Roger D, Vaillant L, Fignon A, et al. (1994). Specific pruritic dermatoses of pregnancy: a prospective study of 3192 women. Arch Dermatol, 30: 734-39.

Rudolph CM, Al-Fares S, Vaughan-Jones SA, et al. (2006). Polymorphic eruption of pregnancy: clinicopathology and potential trigger factors in 181 patients. Br J Dermatol, 154:54-60.

Taylor D, Pappo E, Aronson IK. (2016). Polymorphic eruption of pregnancy. Clin Dermatol, 34(3):383-91.