PP has an estimated incidence of 1 in 450 pregnancies.11 Although many authorities consider EP to be the most common dermatosis of pregnancy, no clear estimation of its prevalence has been established.23,24 Taken together, the two conditions have the highest prevalence of all pregnancy-induced dermatoses.
PP is also known as popular dermatitis of Spangler, Nurse’s early prurigo of pregnancy, and linear IgM disease of pregnancy.3,4,23
Presentation. The typical presentation is grouped, crusted, erythematous papules, patches, and plaques—frequently with excoriations. Lesions typically present on the extensor surfaces of the arms and legs or on the abdomen (FIGURE 4).4 Recurrence in later pregnancies is common.
FIGURE 4 Eczema of pregnancy
EP/PP typically manifests as grouped, crusted, erythematous papules, patches, and plaques, often with excoriations.
Pathophysiology. The pathophysiology of EP/PP is not understood. Many patients who develop EP/PP have a history of atopy.10
Differential diagnosis. Conditions that need to be considered in making the diagnosis include Tinea infection, scabies, contact dermatitis, ICP, pruritic folliculitis of pregnancy (PFP), and PG.
Diagnosis. The history and the physical examination determine the diagnosis. Serology, histopathology, and immunofluorescence are nonspecific. Correlation of EP/PP with increased IgE is marginal, at best.24,25
Treatment. These conditions are treated symptomatically with topical corticosteroids or systemic antihistamines.
Sequelae. No increase in maternal or fetal morbidity or mortality is associated with EP/PP.
5. Acute pustular psoriasis of pregnancy
Whether or not acute pustular psoriasis of pregnancy (APPP) is actually a pregnancy-induced dermatosis is subject to debate.
There is evidence that APPP is not unique to pregnancy but simply a manifestation of ordinary psoriasis. Clinically and histologically, APPP is indistinguishable from pustular psoriasis. Unlike most cases of acute psoriasis, however, APPP often appears in pregnancy without any personal or family history of psoriasis and usually ceases when the pregnancy ends. This fact, combined with reports of increased fetal and maternal morbidity and mortality associated with APPP, leads us to include it here.26
Presentation. APPP is a rare condition that may have an onset at any point in pregnancy. Characteristic lesions begin as erythematous plaques with pustules on the inner thighs, flexural areas, and groin and spread to the trunk and extremities. As plaques enlarge, their center becomes eroded and crusted.
The nails may become onycholytic. Hands, feet, and face are usually spared. Oral and esophageal erosions can occur. Pruritus is typically mild, although the lesions are often painful. Flu-like symptoms are often present.27
Pathophysiology. The pathophysiology of APPP is unknown.
Differential diagnosis. Conditions with similar presentations include an adverse drug reaction, pityriasis rosea, lichen simplex chronicus, eczema, lupus, and pityriasis rubra pilaris.
Diagnosis. The clinical history and an association with systemic illness are the basis for a diagnosis of APPP. Cultures of pustules are negative for any infective pathology, although, as the disease progresses, pustules may become superinfected. Laboratory testing may show an increased erythrocyte sedimentation rate, hypocalcemia, and a low level of vitamin D.
Treatment. Prednisone, 15 to 60 mg/d, is often sufficient to control the disease.27 Cyclosporine, 100 mg twice daily, has also been shown to be useful.28 Cyclosporine in pregnancy is a Category C drug. Data on fetal malformation associated with cyclosporine therapy are limited, but risk appears minimal.6
Maternal hypocalcemia should be monitored and treated appropriately. If disease progression is judged serious enough, early induction of labor is indicated, because delivery will almost always lead to swift resolution.
Sequelae. A number of case reports link APPP to serious sequelae, including fetal growth retardation, hypocalcemia, and stillbirth.27,29,30 The condition is too rare, however, for good data on specific sequelae. Although APPP does give significant cause for concern, it appears that some of the traditional apprehension comes from older publications reporting a rate of maternal mortality of 70% to 90%.31 This statistic has not been borne out in practice. It does appear that the mother will frequently suffer systemic symptoms, including fever and malaise.
6. Pruritic folliculitis of pregnancy
Accounts of the prevalence of pruritic folliculitis of pregnancy (PFP) vary widely. Some sources report fewer than 30 cases in all of the literature; others indicate that the prevalence is equivalent to that of PG—one in every 10,000 pregnancies.3,11 PFP most often presents in the third trimester. It often resolves before delivery, but uniformly clears within 2 weeks of delivery.
Presentation. PFP presents as papules and pustules concentrated around hair follicles (FIGURE 5). Often, lesions begin on the abdomen and spread to the extremities.24,28 The condition is often, but not always, pruritic. Patients are more likely to be concerned about what the condition means for their health than distressed by the symptoms.
