Helga Pfeffunkel is a frequent visitor to Dr. Loregaard's clinic in Teras Terrace, demanding treatment for all sorts of imagined ailments. Dr. Loregaard is happy to cater to her requests, given that she has the money to pay handsomely for it... Helga alone is personally responsible for a sizeable fraction of Dr. Loregaard's income. Her wealth comes from a youthful cornering of the zabroge market, though no one has been able to explain adequately to the Mongleys exactly what a zabroge is. (Explanations like "It's kind of like a walnut, but bigger, and you don't usually eat it" or "It's like a cross between a screwdriver and something that isn't a screwdriver" don't help much.)
What's ironic about Helga's hypochondria is that she actually does seem to be highly disease-prone. At any given time, she shows signs of suffering from any number of different disorders. But whether she's constantly sneezing or covered with bulging pustules or her limbs are falling off, she seems completely unfazed by and in fact practically oblivious to these obvious symptoms, fretting instead about various other, completely unrelated illnesses she's convinced she has.