Pregnancy and rash: related or not related? Medscape

30-year-old, 34 weeks pregnant female, two healthy children. She complains of an increasing rash that has evolved over 4 weeks. It started on her limbs and then trunk, abdomen, including umbilicus, and neck, not compromising her face. The rash, which is very itchy, is urticariform, persistent in the same places, with confluent lesions especially on trunk, and some crusted papules on her extremities. Mucous membranes not involved. Abdomen US is normal. The biopsy revealed a perivascular and interstitial dermatitis with numerous eosinophils, without signs of PUPPP or Erythema Multiforme. There were no blisters and no signs of vasculitis or granulomas. DIF was negative for C3, IgA, IgG, IgM and fibrin. The dermato pathologist opined that the biopsy could be compatible with Adverse Drug Reaction, due to the large amount of eosinophils. The patient  felt better after she stopped the vitamins. After she had suspended the vitamins, and the rash had virtually disappeared in neck, upper limbs and abdomen, persisting some lesions on thighs. So a new biopsy was not necessary and the final diagnosis was "Adverse Drug Reaction" to the vitamins she had been taking.