"It's spread person to person by germs. It's difficult to keep the hygiene going when you have too many people in the house," he says.
Another skin infection called impetigo, or "school sores", begins with pimples and sometimes develops into big oozing bubbles which grow bigger every day.
Dr Didsbury also sees many children with respiratory, or breathing, illnesses caused by cold, damp houses which families can't afford to heat.
"In the winter, we and Middlemore [Hospital] are inundated with young children with bronchiolitis, a wheezy condition," he says.
"Now and again we see rheumatic fever, which for most developed countries is never heard of. It's almost an embarrassment that we see it."
He sees extended families crowding into one house to save money. "Mum and Dad are often in the garage while the grandparents and kids have taken over the main house," he says.
ProCare employs community health co-ordinators who advocate for families to get them bigger houses from Housing NZ, to get their homes insulated with the Government subsidy and to get all their entitlements from Work and Income.
Dr Didsbury says most South Auckland general practices are also on the Government's "very low-cost access" funding scheme which sets maximum fees of $17 for adults, $11.50 for children aged 6 to 17 and zero under 6. But even those fees still put some families off.
Ultimately, he says, lifting health outcomes requires lifting low-end incomes. "If we really want to solve some of the disparities our communities experience, it has to be about education, employment and income."
THE SERIES
Monday: The widening gap.
Tuesday: Tax & benefits.
Yesterday: Housing.
Today: Health.
Tomorrow: Education.
Saturday: What to do?
