MD Milos Kupresak - Ostetrics - PHYSIOLOGIC SKIN CHANGES DURING PREGNANCY

PHYSIOLOGIC SKIN CHANGES DURING PREGNANCY

Hypermelanosis

Hypermelanosis, or darker than constitutive skin color, occurs in 90 percent of pregnancies. Darkly complected women are more likely to manifest hypermelanosis during pregnancy. The hypermelanosis may be generalized or localized to areas of increased melanocyte density. The areolae, umbilicus, vulva, and perianal skin may darken as early as the first trimester. The linea alba often becomes the hyperpigmented linea nigra. Pigmented nevi, freckles, and recent scars may also deepen in color.

Melasma, or chloasma, is an acquired facial hypermelanosis. It manifests with symmetric, well-defined hyperpigmented patches distributed on the cheeks, chin, eyebrows, nose and upper lip. Melasma affects at least 70 percent of pregnant women, with equal racial predilection.[Besides pregnancy, melasma can affect patients on oral contraceptive pills; with liver disease, hyperthyroidism, and nutritional deficiencies; and as a phototoxic reaction to certain cosmetics and medications. Melasma also uncommonly affects males, even in the absence of the above disorders or medications.

The pathogenesis of melasma is unknown. The role of hormonal factors such as melanocyte-stimulating hormone (MSH) is unclear. Levels of estrogen which, like MSH, can stimulate melanogenesis, are not consistently elevated in women with melasma.

Ultraviolet (UV) radiation exposure, including sunlight, accentuates the hyperpigmentation. Patients with melasma should protect themselves from UV exposure by avoiding the most intense hours of sunlight, seeking shade, wearing shading clothing including a hat, and applying a broad-spectrum UV sunscreen of sun protection factor (SPF) 15 or greater. Melasma normally regresses or disappears in the majority of women. However, nearly 30 percent of patients will have persistent hyperpigmentation at 10 year follow-up.

Women with persistent melasma may be treated with 2 to 4 percent hydroquinone cream combined with sunscreen applied in the morning. Hydroquinone cream combined with retinoic acid 0.05 to 0.1 percent cream, and hydrocortisone 1 percent cream also appear to improve the condition, perhaps more rapidly. Other options include chemical peels with trichloroacetic acid or glycolic acid performed postpartum by an experienced dermatologist. Consistent sunscreen use must continue to avoid recurrence of melasma.

Melanocytic Nevi and Pregnancy

During pregnancy, some melanocytic nevi ("moles") may increase in size, and new nevi may develop, If atypical clinical features are present, one may need to biopsy a suspicious pigmented lesion to rule out dysplasia or melanoma. A recent study of pregnant women without multiple nevi or a family history of melanoma showed no significant change in the sizes of their pigmented nevi. However, a special subgroup of women with the "atypical mole syndrome" appear to be at increased risk for dysplastic changes during pregnancy. These women have a family history of melanoma and multiple clinically atypical nevi. The atypical mole syndrome itself in these pregnant women who were objectively studied more likely accounted for the dysplastic changes noted in the moles rather than the pregnancy.

Studies to date have not provided evidence that hormonal changes during pregnancy put the pregnant patient at increased risk of melanoma. Although there are detectable estrogen-binding proteins on melanoma cells, there are no estrogen or progesterone receptors.

When a pregnant woman is diagnosed with melanoma, the pregnancy does not adversely affect her prognosis, Because melanoma incidence overall is increasing, all pregnant women with mole changes including asymmetry, increase in size or elevation, irregular border configuration, or variegation in color should be examined with the same care and scrutiny as all individuals with mole changes.

Hair Changes
Hirsutism

Hirsutism is excessive coarse, or terminal, body hair growth. Mild hirsutism commonly affects pregnant women. The face is frequently affected, though terminal hair growth may be pronounced on the extremities as well. Terminal hairs grow less commonly on the abdomen during pregnancy. Hirsutism is believed to be primarily an endocrinologic phenomenon. During normal pregnancy, the proportion of hair in the anagen (growing) phase is higher than that in the telogen (resting) phase. Hirsutism may result from placental androgen production during normal pregnancy. Mild hirsutism rarely requires therapy. It normally regresses following delivery, but does recur with subsequent pregnancies. Severe hirsutism with virilization should warrant investigation for an androgen-secreting tumor.

Telogen Effluvium

The normal hair cycle consists of three phases: anagen, the growing phase; telogen, or resting phase; and catagen, or the transitional phase in between anagen and telogen. Telogen hair normally sheds due to reactivation of the hair follicle with the beginning of anagen hair growth. Eighty to ninety percent of hairs are in anagen, compared to 13 percent, on average, in telogen. Telogen effluvium, or hair loss after a proportional increase of anagen hairs becoming telogen, is often seen 4 to 6 months into the postpartum period, with average hair loss at two to three times the normal rate of 100 scalp hairs per day. The postpartum drop in estrogen levels precipitates telogen effluvium. Patients should be reassured that normal hair growth will occur 6 to 15 months postpartum, with reestablishment of normal hair cycle proportions. However, in rare circumstances, the hair may not return to its prepregnancy thickness. Persistent alopecia may indicate thyroid dysfunction or low iron stores.

Striae Distensae

Striae distensae, thin atrophic pink or purple linear bands that appear on the abdomen, breasts, and thighs, begin in the late second trimester in up to 90 percent of pregnant women. Striae likely result from a combination of two factors. Stretching produces striae. Also, adrenocorticosteroids and estrogen promote tearing of the collagen matrix of the dermis and weakening of elastic fibers. Electron microscopy demonstrates rearrangement and reduction of fibrillin fibers in biopsies of striae. Most striae fade postpartum to thin flesh-colored atrophic bands.
Although treatment of early striae with topical retinoic acid improves stretch marks, retinoids, even used topically, are contraindicated during pregnancy due to the potential risk of absorption and teratogenicity. Treatment of striae with a 585-nm pulsed dye laser increases dermal elastin and results in clinical improvement. A trial of topical treatment of striae using glycolic acid and tretinoin versus glycolic acid and topical ascorbic acid demonstrated equal improvement and increased elastin after 12 weeks of daily application. Despite these therapeutic advances, no evidence demonstrates complete resolution of striae with treatment.

Vascular Changes

Most pregnant women exhibit vascular changes within the skin. High levels of estrogen cause proliferation of cutaneous blood vessels. Vasomotor instability may also produce pallor, flushing, and mottling of the skin in response to temperature changes. Scattered petechiae may manifest on the lower extremities due to increased cutaneous capillary hydrostatic pressure and fragility common in late pregnancy. Mucous membranes may also manifest vascular changes; gingival swelling during gestation gives rise to pregnancy gingivitis.

Spider angiomata occur in up to 70 percent of white women during pregnancy.[1] Blood quickly refills a compressed spider angioma from a central arteriole outward to tortuous radiating capillaries; the shape resembles a spider. One sees spider angiomata distributed sparsely on the face, trunk, and upper extremities, areas drained by the superior vena cava. Most lesions fade within 3 months during the postpartum period. Hepatic cirrhosis also causes spider angiomata, likely due to higher circulating estrogen levels.

Similar to spider angiomata, palmar erythema affects two thirds of pregnant women. Erythema of the thenar and hypothenar eminences may occur as early as the first trimester as a result of a sixfold increase in blood flow to the hands. Hepatic cirrhosis, systemic lupus erythematosus, and hyperthyroidism also cause palmar erythema. When a manifestation of pregnancy, palmar erythema typically resolves following delivery.

Small capillary hemangiomas may occur during the second and third trimesters in up to 5 percent of pregnant women. Unlike spider angiomata, these lesions do not completely compress. Most small hemangiomas will involute after delivery. Large hemangiomas may persist and rarely are associated with arteriovenous shunting and high-output cardiac failure.

Pyogenic granuloma , also called granuloma gravidarum, occurs in 2 percent of pregnant women. Usually solitary, a pyogenic granuloma develops rapidly as a brightly erythematous sessile or pedunculated friable papule with a collar of thickened epidermis at its base. They can be distributed anywhere on the skin or mucous membranes. Most women seek attention because of the granuloma's rapid growth and recurrent bleeding. This lesion consists of capillary proliferation and mixed inflammatory infiltrate, similar to granulation tissue. Pyogenic granuloma is thought to be an abnormal tissue response to trauma. However, most patients report no trauma history. Although these masses usually remit during the postpartum period, surgical excision may be required if the lesion fails to resolve.