Dermatological issues in pregnancy

Pregnancy is associated with multiple normal physiological changes affecting the endocrine, cardiovascular, and immune systems of the mother. These changes can be reflected in the skin, hair, and nails of pregnant patients in the form of a wide range of dermatological complaints.

article will discuss normal and abnormal dermatological issues commonly associated with pregnancy, as well as how pregnancy affects pre-existing skin conditions. It will also look at medications that are safe for use in dermatological disease during pregnancy and those that should be avoided.

Normal skin changes of pregnancy

Pigmentation of the skin is common in pregnancy. Linea nigra affects about 90 per cent of pregnant women and appears as a vertical line of hyperpigmentation that runs down the middle of the abdomen. It can also be associated with pigmentation of the nipples, areolae, and genital regions. The pigmentation generally fades after pregnancy, but often does not completely resolve.

Melasma is patchy hyperpigmentation affecting the cheeks, forehead, and temples. It usually occurs in the second half of pregnancy and fades completely after delivery. Both linea nigra and melasma are more common in women with darker complexions. Melanocytic naevi, or moles, also commonly show transient changes in their appearance during pregnancy. However, any signs concerning for melanoma must be promptly investigated.

Striae gravidarum, also known as ‘stretch marks’, are very common in the second and third trimester of pregnancy. They are pink or purple atrophic marks affecting the abdomen, thighs, and buttocks, appearing perpendicular to lines of skin tension. The discolouration fades with time, but often some residual change remains after delivery. Bio-oil and massage techniques can be tried in severe cases, but no treatments have proven to be very effective.

Other common findings in pregnancy include palmar erythema and spider telangiectasias, which are related to changing hormone levels. Nail changes such as leukonychia, nail pigmentation, onycholysis, and ingrown toenails are also common. An increase in eccrine gland activity is also frequently seen in pregnancy and may present clinically as hyperhidrosis or milia.

Common conditions in pregnancy

Pyogenic granulomas are benign proliferations of capillary blood vessels that occur on the skin and oral mucosa. Their incidence is increased in pregnancy. As is common with dermatological terminology, the name pyogenic granuloma is a misnomer, as the nodules are neither infectious nor granulomatous. They present as painless, red nodules, typically less than a centimetre in diameter, and can bleed quite profusely with minor trauma.

Pyogenic granulomas are usually quite apparent clinically; however, it is important to note that amelanotic melanoma is an important differential diagnosis. If there is any diagnostic uncertainty, a biopsy should be performed. Pyogenic granulomas can be managed with destructive treatments, topical therapies, or with surgical procedures. In the case of pregnancy-associated pyogenic granulomas, resolution post-partum is common. If there is no significant bleeding, then managing conservatively until after delivery is reasonable.

Telogen effluvium is a type of non-scarring hair loss that has multiple causes, with pregnancy being one of the most common. This transient form of alopecia presents as diffuse hair loss, usually in the first few months after delivery. In normal conditions, the majority of hair follicles contain actively growing hair, which is said to be in the anagen phase. The telogen phase is the resting stage of the hair follicle and the phase during which the hairs loosen and fall out naturally. Approximately 15 per cent of hairs in the healthy scalp are in this stage.

In a patient with telogen effluvium, a large proportion of their hair switches into the telogen phase, meaning it is no longer growing and is naturally inclined to shed. There are lots of known triggers for telogen effluvium including severe illness, hyper and hypothyroidism, psychological stress, and certain medications. The hair loss occurs two-to-four months after the stressor, meaning that in pregnancy, it is usually post-partum. Normal regrowth of the hair usually occurs, but repeated episodes of telogen effluvium can develop into female-pattern baldness.

Conditions specific to pregnancy

There are some dermatological conditions that are specific to pregnancy. Polymorphic eruption of pregnancy (PEP) is a self-limiting inflammatory dermatosis occurring usually in the third trimester or shortly after delivery. The condition is also known as pruritic urticarial papules and plaques of pregnancy, and presents with very itchy, erythematous papules which start within striae, most commonly on the abdomen.

The umbilical region is spared and the papules often demonstrate a white halo around their edge. The rash then spreads towards the peripheries and the papules may coalesce into large urticarial plaques. Most cases of PEP occur in a first pregnancy and an affected mother is very unlikely to develop the rash in subsequent pregnancies. The eruption tends to last for four-to-six weeks, usually resolving two weeks postpartum.

Symptom management is the goal of treatment. Mid-to-high potency topical steroids are useful as the first-line treatment. In severe cases, short courses of oral steroids can also be considered. Antihistamines to relieve itching are also often necessary. As with all treatments in pregnancy, cautious prescribing is important, and discussion with the patient’s obstetrician should be considered if there is any doubt.

Pemphigoid gestationis is a rare autoimmune blistering disorder of pregnancy. It occurs most often in the second and third trimester. In its early stages, it may be difficult to distinguish from PEP as it is itchy and can begin as urticarial plaques and papules on the abdomen. However, in contrast to PEP, pemphigoid gestationis classically forms around the umbilicus. The eruption then spreads rapidly and begins to form tense blisters, sometimes affecting the entire body surface area. Mucous membranes are usually unaffected.

FIGURE 1: From left-to-right: Linea nigra, striae gravidarum, palmar erythema (photos courtesy of dermnetnz)

FIGURE 2: From left-to-right: Pyogenic granuloma, polymorphic eruption of pregnancy, pemphigoid gestationis (photos courtesy of dermnetnz)

Unlike PEP, pemphigoid gestationis is associated with some foetal complications such as prematurity and low birth weights. Occasionally, babies are born with some blisters due to the passage of maternal IgG antibodies across the placenta. In general, however, the foetal prognosis is good. For the mother, topical corticosteroids and antihistamines are the mainstay of treatment for symptom control.

Systemic corticosteroids are quite often required in pemphigoid gestationis and, once again, decision-making regarding treatments should be multidisciplinary. Recurrence of pemphigoid gestationis in subsequent pregnancies is common.

Pre-morbid skin conditions in pregnancy

Due to the physiological changes associated with pregnancy, expecting mothers very often report a change in the severity or character of their pre-existing skin diseases. For example, conditions such as skin tags, rosacea, and lupus tend to get worse during pregnancy.

Conversely, hidradenitis suppurativa, a chronic inflammatory disorder of hair follicles, often improves, likely relating to fluctuating hormone levels. Acne can worsen in early pregnancy and then improve into the late second and third trimester, again due to hormonal influences.

Atopic dermatitis and psoriasis are less predictable, with some mothers reporting improvement and some experiencing a deterioration. For the patients whose skin worsens, treatment can be challenging as many dermatological treatments are contraindicated in pregnancy.

Dermatology treatments in pregnancy

As is always the case when prescribing in pregnancy, caution is advised when considering the use of medications to treat dermatological disease. The drug’s summary of product characteristics must always be consulted and a discussion with the obstetrics team should be considered if there is any doubt before prescribing.

Many of the treatments used in dermatology are contraindicated or lack safety data for use in pregnancy. Tetracyclines such as minocycline and lymecycline are very useful and commonly prescribed medications for acne, rosacea, and hidradenitis suppurativa. However, they are contraindicated in pregnancy as they can cause dental staining and poor bone growth in the infant.

In fact, most of the systemic treatments used in acne are contraindicated in pregnancy, including the oral contraceptive pill, spironolactone, and isotretinoin. This is an important consideration given that most cases of acne occur in the teenage years to early 20s.

Methotrexate, a staple in the treatment of many inflammatory dermatological conditions, is also contraindicated in pregnancy as it is associated with miscarriage and possibly foetal abnormalities.

Topical treatments such as benzoyl peroxide and topical antibiotics are generally safe in pregnancy. Systemic absorption is low and usually the risk-benefit ratio favours their use. Topical retinoids, however, should be avoided in pregnancy due to potential systemic absorption and the teratogenic effects of retinoids.

Topical steroids are an FDA category C medication in pregnancy and their use is considered safe. As with any patient, the lowest potency steroid which is effective should be used. Oral steroids carry certain risks depending on the trimester and consultation with the patient’s obstetrics team is prudent prior to prescribing.

Biologics are becoming increasingly popular for a wide range of inflammatory dermatological conditions, psoriasis being the most common. There are no randomised controlled trials to assess the safety of these medications in pregnancy. The limited data available seem to suggest that they are not associated with adverse foetal or maternal outcomes, but this is based only on case series and small retrospective studies.

It is important to consider, however, that severe, uncontrolled inflammatory skin disorders during pregnancy can confer some risk to both mother and baby. A multidisciplinary discussion regarding pros and cons of the use of biologics during the pregnancy on a case-by-case basis is warranted. In some circumstances, a medication called certolizumab pegol, which is an anti-tumour necrosis factor (TNF) agent, can be useful. It is a pegylated molecule, and therefore does not cross the placenta.

In patients already on biologics trying to get pregnant, switching to certolizumab prior to conception may be a good option. For those who have failed to improve on other treatments and warrant biologic therapy during their pregnancy, it can be safely commenced if needed. In complicated cases such as these, all such decision-making will be undertaken by the patient’s dermatologist in conjunction with the obstetrics team. The mother’s preference as well as risks and benefits should all be taken into account. Many mothers are reluctant to use any systemic medications during pregnancy, and managing skin pathology with topical agents as much as possible until after delivery is often the best and safest course of action.

Summary

There are multiple dermatological issues associated with pregnancy ranging from normal physiological changes to pregnancy-related conditions. Patients with a baseline skin disease can experience no change, improvement, or deterioration in their condition during pregnancy. Treatment of dermatological issues during pregnancy can be challenging and requires careful planning and discussion with relevant specialties.

References on request