If you are someone who suffers from recurrent boils in this area then do please go and see you GP because it may be that you need a cause of antibiotics and an antibacterial wash. If this is a recurrent problem then we often prescribe a longer course of antibiotics to try and break the cycle.
This is because a giardia infection interferes with digestion and inhibits absorption of nutrients from the diet. It can also damage the lining of the intestine. In fact, this particular parasite is at the root of many cases of chronic GI inflammation in dogs and cats.
If Giardia is found in the patient, a careful history should indicate whether this is a reinfection or a treatment failure. A second course of the same drug, for a longer period or a higher dose, should be effective in reinfections, whereas the use of an alternative drug should be effective in true treatment failures.