Synonym: polymorphous eruption of pregnancy (PEP)
Clinical features:
(1) usually onset is during the third trimester, but lesions may appear during the first or second trimester or even after delivery
(2) both papules and erythematous plaques are present. The papules are surrounded by a narrow and pale halo.
(3) small vesicles may also occur
(4) lesions may be present:
(4a) on striae distensae
(4b) over the abdomen and around the umbilicus
(4c) over the thighs and lower legs
(4d) over the back
(4e) over the buttocks
(4f) on the arms
(4g) on the breasts
(4h) occasionally on soles and palms
(5) lesions are typically pruritic which may be severe enough to keep the patient awake at night
(6) lesions may clear anytime from before to 6 weeks after delivery
(7) infrequently recurs on a future pregnancy
Classification of Aronson et al for lesions:
(1) Type 1: pruritic
(2) Type 2: nonpruritic
(3) Type 3: mixed (both pruritic and nonpruritic)
Immunofluorescence testing of a skin biopsy is typically negative, but it may show IgA or C3 or IgM at the dermoepidermal junction and/or around blood vessels.
Features that are uncommon or absent:
(1) lesions on mucus membranes or face
(2) linear deposits at the dermoepidermal junction on immunfluorescence
(3) circulating anti-IgG antibodies (detect on indirect immunofluorescence)
Risk factors:
(1) primigravida
(2) multiple gestational pregnancy
Diagnosis typically requires exclusion of other pruritic conditions.
