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
Atopic eruption of pregnancy
- incidence
- pathophysiology
1 in 300 pregnancies Unifying term that includes: - Eczema in pregnancy - Prurigo of pregnancy - Pruritic folliculitis of pregnancy
Associated with PMHx or FHx of atopy (hayfever, asthma, atopic dermatitis)
Triggered by immunologic changes associated with pregnancy
In ~20%, AEP represents an exacerbation of a pre-existing atopic dermatitis
Atopic eruption of pregnancy
- clinical features
Early pregnancy
- 75% of cases before 3rd trimester
Red / brown excoriated papules on face, neck, flexural surfaces of limbs
Mostly multip
Typically clears within 2 weeks post-natal
Itch resolves with delivery
Atopic eruption of pregnancy
- subclassifications
E-type AEP
- Widespread eczematous eruption involving face, neck, flexural areas (but any area of skin can be affected)
- Skin dryness
P-type AEP - prurigo of pregnancy
- Less common
- Erythematous, excoriated nodules or papules on the extensor surfaces of the limbs and trunk
Pruritic folliculitis of pregnancy
- Rare
- Scattered follicle-based papules and pustules
- Initially on abdomen, may spread to trunk and extremities
- Only mildly pruritic
Atopic eruption of pregnancy
- Treatment
- Fetal effects
- Recurrence
Maintain adequate skin hydration with emollients
Low to mid potency topical corticosteroids
Oral antihistamines
No fetal effects
Tends to recur
Pustular psoriasis of pregnancy
- incidence
- pathophysiology
A.k.a. impetigo herpetiformis
Rare - 1 in 20,000 to 50,000 pregnancies
Variant to generalised pustular psoriasis occurring during pregnancy or triggered by pregnancy
Pustular psoriasis of pregnancy
- clinical features
Typically third trimester (may present earlier or PP)
Pruritus usually absent
Systemic symptoms are severe
- Malaise, fever, anorexia, n/v, diarrhoea, tetany
Symmetric, erythematous plaques studded at the periphery with sterile pustules in a circinate pattern
- flexures, especially groin
Hands, feet and face are usually spared
Oral and oesophageal eruptions may occur
Pustular psoriasis of pregnancy
- diagnosis
- treatment
Skin biopsy
Requires prompt treatment - Systemic corticosteroids Correct hypocalcaemia Fetal monitoring - CTG - USS assessment for fetal growth Early delivery for relief of symptoms and fetal safety sometimes warranted
Pustular psoriasis of pregnancy
- Recurrence
- Fetal implications
Often recurs
Preterm birth Placental insufficiency (with miscarriage, FGR or stillbirth) may occur
