Pregnancy Dermatoses Flashcards by Malindi Haggett

What is the epidemiology of gestational pemphigoid?

Rare, with a prevalence of 1:1700 to 1:50,000 pregnancies

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What HLA associations are linked to gestational pemphigoid?

Ass. with HLA DR3 and HLA DR4, with 50% having both and 100% incidence of anti-HLA antibodies

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In which conditions can gestational pemphigoid occur?

During pregnancy or rarely with trophoblastic tumors (hydatidiform mole, choriocarcinoma)

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What increased risk is associated with gestational pemphigoid?

Increased risk of Graves disease

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What is the pathogenesis of gestational pemphigoid?

Caused by complement fixing antibodies, specifically IgG1 against hemidesmosomes

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Which hemidesmosome proteins are targeted by antibodies in gestational pemphigoid?

BP180
BPAG2
Collagen XVII

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What is the typical onset period for clinical features of gestational pemphigoid?

Can occur during any trimester, typically late pregnancy

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What are the common clinical features of gestational pemphigoid?

Abrupt onset
Pruritic urticarial papules
Clusters of vesicles or tense bullae on an erythematous base

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What areas of the body are most affected by gestational pemphigoid?

Typically affects the abdomen, especially around the umbilicus

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What is a common outcome after delivery for patients with gestational pemphigoid?

Spontaneous remission in weeks to months following delivery

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What are potential triggers for flares of gestational pemphigoid?

Menstruation
Oral contraceptives
Subsequent pregnancies

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What is the effect of gestational pemphigoid on newborns?

10% develop mild skin involvement due to passive transfer of antibodies, resolves within days to weeks

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What increased risks do newborns face if the mother has gestational pemphigoid?

Prematurity
Small for gestational age

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What histological findings are associated with gestational pemphigoid?

Non-specific mixed cellular infiltrate with eosinophils
+/- sub-epidermal blister

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What does direct immunofluorescence (DIF) show in gestational pemphigoid?

Linear deposition of C3 along the BMZ of perilesional skin (100%)
Linear deposition of IgG (30% of patients)

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What is the role of ELISA in diagnosing gestational pemphigoid?

Detects BP180 - NC16A

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What are the differential diagnoses for gestational pemphigoid?

PEP
Drug eruption

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What are the skin-directed therapies for gestational pemphigoid?

Topical corticosteroids
Emollients
Avoid soaps and hot showers

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What systemic treatments are used for gestational pemphigoid?

Antihistamines
Oral prednisolone

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What caution should be taken with high doses of topical corticosteroids during pregnancy?

Fetal growth restriction reported with prolonged use

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What is the management aim for gestational pemphigoid?

Manage symptoms and suppress blister formation

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What should be discussed with patients regarding the risk to their baby?

10% will have skin involvement at birth, resolves within days to weeks

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What is the risk of developing gestational pemphigoid in subsequent pregnancies?

High risk of developing again, often earlier and more severe

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What is the epidemiology of polymorphic eruption of pregnancy?

Common, occurring in 1:160 deliveries

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In which group of women does polymorphic eruption of pregnancy tend NOT to recur?

Primiparous women

What associations are found with polymorphic eruption of pregnancy?

Nil autoimmune associations, nil HLA association

What is the pathogenesis of polymorphic eruption of pregnancy?

Cause is unknown. Hypothesised that rapid stretching of abdominal skin may damage connective tissue, eliciting an allergic-type reaction.

What inflammatory reaction occurs in polymorphic eruption of pregnancy?

Cross reactivity to collagen in other skin leading to a more widespread reaction.

What factors increase the occurrence of polymorphic eruption of pregnancy?

* Increased maternal weight gain * Multiple gestation pregnancies

What are the clinical features of polymorphic eruption of pregnancy?

* Pruritic erythematous to oedematous papules and plaques * Widespread erythema * Target lesions * Vesicles * Eczematous plaques

Where do lesions of polymorphic eruption of pregnancy usually start?

In abdominal striae

What areas are spared by the lesions in polymorphic eruption of pregnancy?

Face, palms, and soles

When do lesions of polymorphic eruption of pregnancy generally occur?

In the latter part of the third trimester (85%) or immediately post-partum (15%)

How long do lesions of polymorphic eruption of pregnancy typically take to resolve?

Approximately 4 weeks

What is the maternal morbidity associated with polymorphic eruption of pregnancy?

No associated maternal morbidity

What triggers are known for flares of polymorphic eruption of pregnancy?

Nil known, possibly rapid stretching of skin

What effect does polymorphic eruption of pregnancy have on newborns?

Nil

What does histology show in polymorphic eruption of pregnancy?

* Non-specific findings * Epidermis: spongiosis, acanthosis, hyperkeratosis/parakeratosis * Dermis: perivascular lymphocytic infiltrate with variable dermal oedema/neutrophils/eosinophils

What are the results of Direct Immunofluorescence (DIF) in polymorphic eruption of pregnancy?

Negative

What are the results of Indirect Immunofluorescence in polymorphic eruption of pregnancy?

Negative

What does ELISA show in polymorphic eruption of pregnancy?

Negative

What are the differential diagnoses for polymorphic eruption of pregnancy?

* Contact dermatitis * Drug eruption * Gestational pemphigoid

What are the skin-directed therapies for polymorphic eruption of pregnancy?

* Topical corticosteroids * Emollients * General measures

What systemic agents can be used for severe pruritus in polymorphic eruption of pregnancy?

* Oral antihistamines * Short course oral prednisolone

What should be discussed with the patient regarding polymorphic eruption of pregnancy?

* Explain the diagnosis * No risk to mum or baby * Treatment options * Risk for future pregnancies

True or False: Polymorphic eruption of pregnancy generally recurs in future pregnancies.

False

What is Intrahepatic Cholestasis of Pregnancy?

A rare complication during pregnancy where the ability to excrete bile salts cannot keep up with the amount produced, leading to bile acid accumulation in the blood ## Footnote It causes severe itching for the mother and can be dangerous for the baby.

What is the epidemiology of Intrahepatic Cholestasis of Pregnancy?

Rare condition, genetically linked (50% positive family history), more common in multiple gestation pregnancies, prevalent in South America (Arucanian Indian women) and rare in Europe and North America.

What genes are associated with Intrahepatic Cholestasis of Pregnancy?

* ABCB4 * ABCB11 * ABCC2 ## Footnote These genes encode bile transporter proteins.

What is the pathogenesis of Intrahepatic Cholestasis of Pregnancy?

Reduced excretion of bile acids leads to increased serum levels, resulting in severe pruritis and toxic effects on the fetus.

What toxic effects can bile acids have on the fetus?

* Acute anoxia * Abnormal uterine contractility * Vasoconstriction of chorionic veins * Impaired fetal cardiomyocyte function

What hormonal factors contribute to Intrahepatic Cholestasis of Pregnancy?

* High levels of sex hormones during pregnancy * Estrogen and progesterone have a cholestatic effect * Hepatitis C viral infection may also have a cholestatic effect.

What are the clinical features of Intrahepatic Cholestasis of Pregnancy?

* Dramatic pruritis, often starting on palms and soles * Pruritis affects extensor surfaces, buttocks, and abdomen * Jaundice occurs in 10% of cases.

What skin findings are associated with pruritis in Intrahepatic Cholestasis of Pregnancy?

* Excoriations due to scratching * Prurigo nodularis * No primary skin lesions.

What are the risks to the mother associated with Intrahepatic Cholestasis of Pregnancy?

* Vitamin K deficiency leading to increased risk of intra and postpartum hemorrhage * Steatorrhea.

What triggers can cause flares in Intrahepatic Cholestasis of Pregnancy?

* High levels of sex hormones * Hepatitis C viral infection * Selenium deficiency * Increased intestinal permeability.

What is the effect of Intrahepatic Cholestasis of Pregnancy on newborns?

* Premature birth (20 - 60%) * Intrapartum fetal distress (10 - 30%) * Fetal loss (1 - 2%).

What laboratory findings are indicative of Intrahepatic Cholestasis of Pregnancy?

* Total serum bile acids >11 μM * Transaminitis is common * Elevated bilirubin levels * Prothrombin time may be elevated if vitamin K deficient.

What are the common features of serum bile acids in Intrahepatic Cholestasis of Pregnancy?

* Serum total bile acid concentrations >11 μM * Cholic acid-to-chenodeoxycholic acid ratio >1.5 * Glycine conjugates-to-taurine conjugates of bile acids ratio <1.

What is the treatment approach for Intrahepatic Cholestasis of Pregnancy?

Multidisciplinary team approach with the aim to reduce serum bile acid levels using: * Oral Ursodeoxycholic acid - 15 mg/kg/day * Skin-directed therapies * Systemic agents like oral antihistamines.

What should be discussed with patients regarding Intrahepatic Cholestasis of Pregnancy?

* Explain the diagnosis * Discuss risks to the mother and baby * Outline treatment options * Address risks for future pregnancies.

What is the recurrence rate of Intrahepatic Cholestasis of Pregnancy in future pregnancies?

Recurrence occurs in 40 - 75% of pregnancies and with oral contraceptive pill use.