Urticarial exanthema due to hepatitis B in a pregnant woman, mimicking a polymorphic eruption of pregnancy.

Hepatitis B virus (HBV) infection in pregnant women is very rare in western countries, thus, cutaneous manifestation of HBV infection may be confused with a dermatosis specific of pregnancy. We report a 39-year-old woman who presented in her 20th week of pregnancy with a pruritic rash, which consisted of generalized erythematous plaques, some of them with a purple centre. Serology testing showed acute HBV infection, and a biopsy revealed a superficial and interstitial perivascular inflammatory infiltrate of lymphocytes and eosinophils. A diagnosis of exanthema due to acute hepatitis B infection was established. The patient delivered a clinically healthy boy, who was given the first dose of the HBV vaccine and intravenous specific immunoglobulin, followed by the second dose 2 months later, and did not get infected with HBV. To our knowledge, this is the first case describing HBV exanthema in a pregnant woman, which led to early action for the newborn, avoiding vertical transmission and its high prevalence of cirrhosis and hepatocellular carcinoma.

Congenital cutaneous Langerhans cell histiocytosis and cutaneous mastocytoma in a child.

Langerhans cell histiocytosis and mastocytoma are clonal disorders of bone-marrow-derived cells, most commonly seen in the pediatric age. Infiltration of mast cells and Langerhans cells in the same lesion has been published before, but, to our knowledge, this is the first time that the occurrence of two mastocytomas and Langerhans cell histiocytosis is reported. It could be hypothesized that both clonal disorders of bone-marrow-derived cells could have a common origin.