A 7 year old Austrian girl presented with a 20-month history of oral thrush as well as onychomycosis of the hands. In addition, dysphagia suggested esophageal involvement. Her family history was negative for chronic mucocutaneous candidiasis (CMC). Prior treatments with systemic antimycotic agents (miconazole, amphotericin B) showed only little relief and were followed by immediate relapses. The initial differential diagnoses were CMC as well as other forms of chronic immunosuppression, including an underlying malignancy such as lymphoma, HIV/AIDS and tpye 1 diabetes mellitus. The initial laboratory examination revealed a positive HIV-ELISA and Western blot, a viral load of 31.000 copies/ml and a severe CD4 cell depletion (94/mm³), leading to the diagnosis of HIV in childhood. After getting an overview about the family situation we realised that the mother had been neglecting her known HIV infection and that the little girl had never been tested before.

Conclusion Screening for HIV infection during pregnancy is the key prerequisite for the prevention of vertical HIV transmission. Testing within the first 16 weeks of pregnancy is obligatory since 2010 according to the Austrian prenatal care guidelines. This case report emphasises the importance of HIV testing during pregnancy. The younger sister of our patient had already benefitted from these guidelines because the mother had been tested positive for HIV for the first time during her third pregnancy, and mother-to-child transmission was prevented by the timely initiation of antiretroviral treatment of the maternal HIV infection.