Dogs can have environmental or food allergies causing red, itchy skin, hot spots, infections & hair loss. Diagnosis & avoidance helps.
Allergies
Overgrowth of yeast on dog skin leads to greasy red patches, itching & odor. Topicals & antifungals treat yeast dermatitis.
Yeast Infections
Staph, streptococcus & other bacteria infect dog skin causing pustules, crusty sores & hair loss. Needs oral/topical antibiotics.
Bacterial Infections
Mites, lice & fleas bite dogs causing mange, which leads to severe itching, redness & hair loss. Treat with anti-parasitics.
Parasites Like Mange
Dogs can develop hives, swelling & itchy skin from allergic reactions to food, vaccines, medication or insect bites. Antihistamines help.
Allergic Reactions
Excess oil production leads to greasy skin, dandruff, odor & secondary infections in seborrheic dogs, requiring medicated shampoos
Seborrhea Skin Issues
Rare autoimmune skin disease causes scaling, crusty lesions & hair loss in dogs. Hard to cure & requires immune-suppressing medication life-long
Autoimmune Disease