Dermatoses of pregnancy Flashcards
Physiological skin changes
Placenta produces melanocyte-stimulating hormone –> increases skin pigmentation
- Existing pigmented areas (areolae, axillae) become darker
- Linea nigra - appearance or darkening of a vertical band down the middle of abdominal skin
Melasma - blotchy, brownish, benign hyperpigmentation on the sun-exposed skin of the face (~70% of women in second 1/2 of pregnancy)
High oestrogen levels –> stretch marks on the abdomen, breast, thighs (striae gravidarum)
Also thin-walled, dilated capillaries (especially lower leg) increase (telangiectasia, varicose veins, spider naevi)
Increased risk of skin infections from reduction in cell-mediated immunity
Increased redness of palms (palmar erythema)
Hair changes in pregnancy
Normal pregnancy increases the amount of hair in the growth phase (anagen) Telogen effluvium (hair shedding) after the baby has been born Occurs in most women 4-20 weeks after delivery
EFFECT OF PREGNANCY ON SKIN CONDITIONS
Shift from predominantly T-helper (Th) 1 lymphocyte profile to Th2 profile explains improvement in some (Th-1 driven diseases, e.g. psoriasis) and exacerbation in others (Th-2 driven diseases, e.g. atopic eczema)
Acne
May develop for the first time in pregnancy
Pre-existing acne may improve or worsen
- Tendency to flare in the third trimester secondary to increased sebaceous gland activity secondary to high levels of androgens
Erythema nodosum
Inflammation of the subcutaneous fat
Presents as tender erythematous nodules over the anterior lower legs
DDx - TB, sarcoidosis
Usually resolves in 2 months
If severe, treat with oral corticosteroids
Psoriasis
Improves in most
- Deterioration in 10-20%
Rx:
- Emollients
- Topical steroids
- UVB light - second line
- inflixamab / cyclosporine - 3rd line
Pemphigoid gestationis
- incidence and pathophysiology
Rare, but serious
1:50,000
Autoimmune, pregnancy specific
Circulating IgG1 autoantibodies against a glycoprotein in the basement membrane zone of the skin –> inflammatory cascade –> separation of the epidermis from the dermis
Associated with bullous pemphigoid, insulin-dependent DM, Graves’, pernicious anaemia, vitiligo, RA
Pemphigoid gestationis
- clinical features
Abrupt onset, anytime, but usually second or third trimester of pregnancy
Intense pruritus may precede the onset of lesions
PERI-UMBILICAL LESIONS
- begins here, then spreads to limbs
Urticarial/erythematous plaques or papules = target lesions (red ring around the outside)
Lesions may be seen on palms and soles
Rarely on face or mucous membranes
Spreads rapidly and forms tense blisters (bullous)
Secondary skin infection may occur
Pemphigoid gestationis
- diagnosis and treatment
Biopsy of vesiculating lesion
- C3 at basement with immunofluorescence
75% flare postpartum
At least 25% flare with oral contraceptive pills or during menses
Most cases spontaneously resolve in the weeks to months following delivery
High potency topical corticosteroids
If symptoms not controlled with topical Rx, then systemic corticosteroids usually effective
Antihistamines may be helpful with pruritus
Cool soothing baths
SERIAL GROWTH SCANS
Fetal implications
Pemphigoid gestationis
Preterm birth (34%)
SGA due to mild placental failure
Stillbirth
Neonatal pemphigoid gestationis
- Newborns present with blisters (occurs in 10%)
- Due to transplacental passage of maternal IgG autoantibodies
- Mild course, resolves within weeks without treatment
Pemphigoid gestationis
Recurrence risk of
Usually recurs, often worse
Polymorphic eruption of pregnancy
incidence
pathophysiology
1 in 200 pregnancies
Also called pruritic urticarial papules and plaques of pregnancy (PUPPP)
Benign, self-limiting
Unknown
More common with excessive stretching, e.g. multiple gestation, greater maternal weight gain
- ? Causes damage to connective tissue –> exposure of dermal antigens –> inflammatory response
Risk factors - primup, LGA, multiple pregnancy
Polymorphic eruption of pregnancy
- Clinical features
Last few weeks of pregnancy or immediately postpartum
- Mean onset 34-35/40
Extremely pruritic, erythematous papules within striae
White halos often surround papules in patients with fair skin
Usually abdominal striae initial site with periumbilical sparing
Lesions then spread to the extremities (thighs, upper arms), chest, back
Face, palms and soles usually spared
Polymorphic eruption of pregnancy
- diagnosis and Rx
Clinical
Skin biopsy only if diagnostic uncertainty
Goal: relief of symptoms
Reassure
Cool soothing baths
Topical corticosteroids
- Mid to high potency
If severe cases, short course of systemic corticosteroids with a quick taper
Antihistamines may be helpful for pruritus
Generally lasts 4-6 weeks and resolves within 2 weeks postpartum
Polymorphic eruption of pregnancy
- fetal effects
None
Recurrence rare