Hello Janet, I'm Dr. Deb.
I recently came online and see that your question about Alfie hasn't been answered. I'm so sorry that you've had to wait for a response,but if you still need assistance, I'd like to help if I can.
It sounds like Alfie may have a staph or skin infection which may or may not be related to the walks he takes in the woods.
Many times these types of infection are secondary to allergies of one sort of another and he's about the right age to develop this sort of problem. Allergies to pollens, grasses, dust mites, mold, etc. can commonly cause skin issues as can allergies to food.
Typically, these dogs are a little itchy which makes their skin issues worse (more itchy) so they continue to lick at them.
If the skin lesions are not numerous, then medicated shampoos may be helpful as will cleaning them twice daily with over the counter dilute Betadine or Iodine (to the color or weak tea) and application of antibiotic ointment. I also recommend Vetericyn which is a skin/wound spray which can be remarkably effective.
However, if the skin lesions are numerous, then systemic antibiotics are often necessary before improvement is seen.
Over the counter anti-histamines such as Diphenhydramine can also help dogs the dose would be dose of 1 mg/lb twice) a day although sedation may be seen. Antihistamines are not universally effective, however, for all dogs with skin allergy issues and sometimes stronger drugs such as steroids are needed.
For suspected food allergies (usually to protein and/or carbohydrate), I recommend taking the label of the current food to the pet store and purchasing something entirely different. If the current protein is chicken (a protein with feathers), then avoid foods with duck and turkey in them; purchase a protein with "hooves", in other words. It might take several weeks before improvement is seen, though.
You might consider treating him as I mentioned above for a few days to see if there's improvement if there aren't too many skin lesions; if there are, then a vet visit would be prudent.
I hope this helps although, again, my apologies for the delayed reply. Deb