MRCS, LRCP Lond 1899; LSA 1898; Kings College London.
Ahrens was MOH for Basingstoke Borough, he was also Surgeon-Major for the Hampshire Carabineers. A Member of the BMA, he had previously worked as House Surgeon at the Royal Ear Hospital and Senior Clinical Aural assistant at King's College Hospital. On the notice of death he is described as 'of Grangethorpe Hospital, Manchester'. He died on 16 April 1929 aged 59 years.