I'm sorry to hear that your fellow Gunner has hairloss and bumps all over him. I understand that your other dogs aren't showing any symptoms.
In a young dog with this sort of description, especially if the pup isn't very especially itchy, I would be highly suspicious of demodectic mange. Demodex lesions are most commonly seen on the face and legs. These are pictures of dogs with demodex mites showing a few lesions on the face and on the side of the body:
In some cases the mites cause symptoms all over the body. This is called generalized demodicosis. Those cases are much more severe and difficult to clear up. See these links for pictures of dogs with generalized demodex:
Demodex mites are present in the hair follicles of all dogs. In some young dogs with immature immune systems or older dogs with immune system suppression from other disease processes the mites get overpopulated leading to hair loss and erythematous skin. In cases where there are secondary bacterial skin infections the dog may be itchy but in most cases they are not.
Your veterinarian can diagnose the demodex mite with a skin scraping or skin biopsy.
Treatment is usually not done if the infection is limited to one spot. We usually simply let the dog's immune system mature and get the mites under control. But in your fellow's case with multiple lesions then treatment is daily ivermectin therapy for a couple weeks past two negative skin scrapings. Once treatment is started we need to be careful not to stop too soon or the mites will be harder to get rid of.
Other possible causes for sparse hair, bumps, and red skin are sarcoptic mange, although those dogs are extremely itchy, a deep bacterial infection, or a fungal infection (ringworm).
Ideally your pup should see his veterinarian for a skin scraping and possibly a fungal culture. A diagnosis will give us an idea of how he needs to be treated.
Please let me know if you have any further questions.