I am very sorry to hear that your pup Homer is licking and chewing his paws.
Allergies are the most common cause of itchy skin, and that makes dogs lick and chew themselves. Outdoor plants, dust mites, mold spores and other indoor allergens are all possible allergens in the air which could explains why he is so itchy.
Dogs that have one allergy often develop several with time. The effect of multiple allergies aren't additive, they actually compound one another so that may be why he seems more itchy this year.
Even if you don't see fleas I do recommend using protection, if only during the spring, summer and fall months in areas with a deep freeze. They are the most common allergen and it only takes one bite a month to make an allergic dog scratch so I recommend using flea prevention even if you never see one again. Frontline Plus, Activyl, Advantage II or Advantix are excellent. Don't use over the counter products, especially Hartz or Sargents, as most are ineffective if not toxic. All pets in the home must be protected even if they don't show symptoms, otherwise they serve as flea reservoirs for the allergic pet.
Allergens that can be inhaled (like grass pollen, dust mites or molds) and flea bite allergy can sometimes be controlled with a combination of antihistamines and high doses of omega-3 fatty acids (they also help with the symptoms of flea allergy). In combination fatty acids and antihistamines work synergistically, much better than either one alone. If his symptoms worsen seasonally I would think that inhaled allergens are a big part of his problem.
You can try:
1)Benadryl (diphenhydramine only don't use the combination products with acetaminophen or decongestants as they can be toxic for dogs) at a dose of 1mg to 2mg per pound of body weight or one 25mg capsule per 15 to 25 pounds of body weight orally every 8 to 12 hours. I know that you have tried Benadryl, but I wanted to make sure that you used a high enough dose for a pup his size.
OR 2)Claritin (loratidine) at a dose of one 5mg per 25-30 pounds of body weight once or twice daily.
OR 3)Hydroxyzine at 1mg per pound of body weight orally every 8 hours.
OR 4) Chlorpheniramine (Piriton) at 4mg to 8mg per dog once or twice daily.
OR 5) Zyrtec (Cetirizine hydrochloride) at a dose of 1/2 mg per pound of body weight orally every 24 hours. That would be one 10mg tablet per 20 pounds of body weight. Make sure it is NOT the formulation with a decongestant (such as Zyrtec-D) because dogs cannot tolerate decongestants.
Some dogs do better on one antihistamine rather than another. In general dogs seem to do best with Zyrtec, but each one is an individual so if that doesn't work I gave you others to try. Pick one, give it a week trial and if it isn't working try another. Be aware antihistamines can cause sleepiness or hyperactivity in some dogs. These side effects do wear off with repeated use.
Omega-3 fatty acids are fish oil products. 3V by DVM or Derm Caps ES are good brand name products. Use the high end of the dosing schedule for your pup's weight, meaning if he is between doses work your way up to the higher dose. I recommend a dose based upon the EPA portion (eicosapentanoic acid) of the supplement as if we do that the rest of the supplement will be properly balanced. Give him 20mg of EPA per pound of body weight per day. For example a 50 pound dog could take 1000mg of EPA per day.
Cool water spot bathing of his paws with an oatmeal shampoo or chlorhexiderm shampoo (which is antibacterial and antifungal) and a conditioner with an antihistamine may help. The water rinses off allergens and the cool temperature soothes itchy skin. Just make sure to dry his feet well afterwards.
Food allergy is very possible with him as food allergic dogs often have very itchy feet, and food allergic dogs may or may not be helped by steroids (Temaril-P). If he was being fed something different then started being itchy I would suspect food allergies. But dogs can develop allergies to any protein or carbohydrate so even if he is only fed one thing that can be what he is allergic to. Dogs with food allergies tend to lick and scratch their paws, perianal area, face and ears the most, but any of the "allergy reactive areas" can be affected. Limited ingredient pet store diets may not be restrictive enough. The trouble with "limited ingredient" or "low allergy" pet store brands is that the same machinery is used on multiple lots of food without sterilization cleaning in between. So for example even if a food says it has salmon and rice if the previous batch had beef and corn then you will get traces of those ingredients in your bag of food. Not a big deal if your dog isn't allergic but a waste of money thinking that the food was hypoallergenic and not good for your dog if those happen to be allergens for your dog. The veterinary brand true hypoallergenic foods are more expensive because it isn't cheap to thoroughly remove all traces of a previous food mixture from the machines used to process food but I believe they are worth it. You could try a true hypoallergenic diet like Hills z/d or Purina Veterinary Diets HA. No treats, flavored medication or bones while on the diet and it must be used for a least 12 to 16 weeks to see the full effects.
Cortisone ointment applied to the very itchy places (as long as they aren't raw) twice daily may help as well if needed. Some sprays have alcohol which can be painful on raw skin and lead to more inflammation. Topical treatment directed at the problem areas can be very helpful and are less likely to cause side effects compared to systemic steroids.
Another option if the antihistamines and omega 3's aren't enough is a product called Atopica. It suppresses the immune system a bit so it decreases allergic symptoms but it doesn't have as many harmful side effects as systemic steroids.
Another option is a newer drug called Apoquel (generic name oclacitinib) which interferes with the allergic pathway. It works very quickly to stop the symptoms of inhaled and flea allergy symptoms, but seems less effective at controlling food allergy symptoms. Most dogs are reported to be much more comfortable in a day or so. If you are interested discuss these medications with your veterinarian as they are prescription products.
It is possible that with all of his licking and chewing he may have a secondary yeast or bacterial infection on his feet now. Either of these would make his feet even more itchy. Your veterinarian can take a skin swab and look at the debris under the microscope. Depending upon what is found he may need a course of oral antibiotics or antifungal medication.
If it's been a while since his last exam parasites like demodex or sarcoptes mites should be looked for as well as both lead to very itchy skin and are seen with some frequency affecting the feet.
Please let me know if you have any further questions.