SAN FRANCISCO – When a pregnant woman presents with a complaint of itching, consider a range of causes, not just those triggered by pregnancy, Dr. Bethanee J. Schlosser advised.
Although some dermatoses of pregnancy are common, a pregnant woman's itching may have nothing to do with her pregnancy and could be the result of contact dermatitis, drug eruption, scabies, folliculitis, or another cause, Dr. Schlosser said at the meeting sponsored by Skin Disease Education Foundation (SDEF).
“Just because they're pregnant doesn't mean they only have to fit in the pregnancy dermatoses box,” Dr. Schlosser of the department of dermatology, and director of the women's skin health program, at Northwestern University in Chicago, said in an interview.
With that said, the two most prominent dermatoses of pregnancy are pruritic urticarial papules and plaques of pregnancy, a condition now known under the umbrella term polymorphic eruption of pregnancy, and pemphigoid gestationis, previously called herpes gestationis.
Polymorphic eruption of pregnancy occurs in about 1 in 300 pregnancies and is generally associated with multiple gestations and increased maternal weight gain. It is also more common in women having their first child. The mean onset is at about 35 weeks, but in about 15% of cases, the onset can be post partum, according to Dr. Schlosser.
Pemphigoid gestationis is a rare acquired autoimmune blistering disease unique to pregnancy. It occurs in 1 in 50,000 pregnancies and is probably the least common dermatosis of pregnancy. The onset is usually in the second or third trimester, but in about 14% of cases, the onset can occur post partum. With pemphigoid gestationis, there is no change in maternal outcome, but there are risks to the fetus including being small for gestational age, preterm delivery, and neonatal pemphigoid disease.
Typically, patients with the polymorphic eruption present with “hivelike” or urticarial papules and plaques, but no blisters, while women with pemphigoid gestationis often have more blistering. However, the clinical presentations and the routine histopathology can be identical, she explained. “I've seen patients with both entities, with both kinds of clinical features,” she noted. “If it's in your differential diagnosis and you can't distinguish 100% clinically, then that's where the utility of biopsy comes in.”
Cutaneous biopsy is a common procedure and is low risk, she reported, even in the context of pregnancy. Routine histopathology and direct immunofluorescence are essential in terms of differentiating between pemphigoid gestationis and polymorphic eruption.
The first-line treatment for both conditions is topical corticosteroids and oral antihistamines when the condition is mild or localized and systemic corticosteroids in severe cases. Although the treatments are generally the same, the difference between the two conditions is not academic, she said, because the potential sequelae and considerations for mother and child are different.
Dr. Schlosser also recommended that dermatologists make it a priority to communicate with the referring physician, specifically to review the risks to both the mother and child that may be associated with a particular skin condition or its treatments. For example, polymorphic eruption of pregnancy is generally nonthreatening to the mother and child. But Dr. Schlosser said she has seen patients with widespread, severe polymorphic eruptions who have needed treatment with systemic corticosteroids. That's essential information for the ob.gyn.; if the patient has a cesarean delivery, the patient will likely require stress-dose corticosteroids. Similarly, the newborn would need to be monitored for hypoglycemia during the immediate after-birth period.
“That doesn't mean that dermatologists shouldn't treat pregnant women aggressively, when appropriate,” she said. “But the entire multidisciplinary care team needs to be kept informed so that the risks can be managed.”
Erythematous edematous papules and vesicles are evident on the palm in in this case of pemphigoid gestationis.
Source Photos courtesy Dr. Bethanee J. Schlosser