Rashes and Itching in Pregnancy - Part 2

This article is part 2 of a two article series describing the different skin conditions/rashes that can occur in pregnant women. Here, we will focus on the following conditions: pemphigoid gestationis, intrahepatic cholestasis of pregnancy, and impetigo herpetiformis. Please refer to part 1 of the series for further information on the various skin conditions discussed.^[1]

Pemphigus Gestationis (Herpes Gestationis)

Pemphigus gestationis is very rare, with around 0.025% of pregnancies being affected. It usually starts with intense itching and later follows with red bumps which transform into blisters over the next several weeks. These blisters eventually burst, leaving areas of eroded skin. The bumps can appear anywhere on the body (even the mouth, eyes, and genitals) but most commonly occur on the abdomen around the belly button. Most women notice the start of this condition during the second and third trimesters, but it can occur at any time during the pregnancy and even shortly after delivery.^[2] 

It is reported that around 5-10% of newborns can be affected by pemphigus gestationis as well because the molecules responsible for the disease (known as antibodies) in the mother can pass through the placenta and reach the baby’s bloodstream. However, most infants are affected with only a mild form of the disease that does not require systemic treatment. The infant’s disease usually lasts less than a month, as the baby’s body rids itself of the culprit antibodies. There is a slightly increased risk of prematurity and low birth weight in babies thought to be related to both the disease and frequent use of steroids to control the disease.^[1]

For the mother, treatment can vary depending on the severity of the condition. For mild forms of pemphigus gestationis, topical steroids and soothing ointments can relieve the itchiness and pain of blistering. Antihistamines, draining of blisters, appropriate wound care (silicone gauzes, protective ointments), and cool compresses may also be used to relieve symptoms. For more severe cases, oral steroids are needed to control the disease. A common regimen is 20-40 mg of prednisolone daily for 1-2 weeks with tapering to a lower effective daily dose if improvement is seen. Commonly, the disease flares around delivery and the steroid dose is increased at that time. Most women are typically able to come off steroids within a few weeks after delivery. This disease can and does recur in subsequent pregnancies.^[3]

Intrahepatic Cholestasis of Pregnancy (ICP)

Interestingly, intrahepatic cholestasis of pregnancy (ICP) is primarily a liver disease but has such severe skin manifestations that it is often discussed and grouped together with other skin conditions of pregnancy. Women with this condition complain about severe itching usually on the palms and soles, but whole-body itching can also occur. The condition is not accompanied by a rash, but the itching can be so severe (especially at night) that the itching can lead to skin damage and a rash.^[4]

Intrahepatic cholestasis of pregnancy (ICP) is related to liver dysfunction and elevated levels of bile acids (substances metabolized by the liver and used to absorb fat from the intestines) in the blood. The itching is thought to be directly related to increased concentrations of bile acids, but the mechanism of action is unclear. Evidence from recent experiments suggests that bile acids activate nerves in the skin to trigger the itch.^[4]

Unfortunately, this diagnosis can be dangerous for a developing fetus. ICP is associated with an increased risk of premature birth, fetal distress, and to a lesser extent, stillbirth. It is recommended that weekly fetal heart monitoring begin at 34 weeks, and an Ob/Gyn physician may elect to induce labor early at 38 weeks, or in severe cases, at 36 weeks once the baby’s lungs have developed.^[1]

The treatment for the mother primarily consists of controlling the symptoms of itch. The gold-standard treatment for this is the use of a substance that lowers bile acid concentrations called ursodeoxycholic acid, which must be taken daily. Fortunately, the itching symptoms often go away within a few days of delivery and treatment can be stopped at that time.^[1] 

Impetigo Herpetiformis (Pustular Psoriasis of Pregnancy)

Impetigo herpetiformis is characterized by pustules (small pus-filled bumps), which can be scattered all over the body. These pustules are usually yellow-green in color and situated on a red background. The lesions often burst and have a weepy crusted appearance. The onset of rash is also associated with other severe whole-body symptoms such as fever, chills, pain, nausea, vomiting, diarrhea, seizures, and general tiredness, to name a few.^[1]

The mechanism of disease is not clear. Several reports suggest that the disease may have a familial/hereditary component. However, there have been cases of patients without any family history also affected by this condition. It is important to recognize this disease early because it can have adverse effects on the health of the baby.^[5]

Impetigo herpetiformis can be dangerous for the baby even if the mother is adequately treated. The use of corticosteroids, as well as the condition itself, can cause problems with the placenta which can lead to compromised health of the growing fetus. There is an increased risk for stillbirth, death of the newborn, and birth abnormalities.^[1]

A woman diagnosed with this condition must be treated due to the high morbidity (high likelihood of other negative health effects on the body) of the disease. The first-line treatment is oral (systemic) corticosteroids (usually doses of 15-30 mg/day). If this is ineffective, cyclosporine may be used although it is categorized as pregnancy category C (unknown or potential risk to the baby). Calcium, vitamin D, and light therapy (UVA) have also been used with some success in these patients. Most women improve after delivery and can be treated with retinoid-derived (vitamin A-derived) medications. This condition tends to occur with each subsequent pregnancy for many women.^[6]

Part 1 of this article series focuses on polymorphic eruption of pregnancy along with papular dermatoses of pregnancy and its many subsets.