Brownish, fairly large, two or three patches, mainly on the rear of the body, on the skin. Parting the fur and touching it makes the dog flinch in pain.

Based on the photo you sent, the dog shows scabs or dandruff, and if pain is present it may be caused by trauma. A mixed bacterial and fungal infection cannot be ruled out either.

Shave the fur around the affected area and spray a wound-infection spray locally. During treatment keep an Elizabethan collar on the dog to prevent it from scratching the wound. If the condition shows signs of spreading, take the dog to a veterinary hospital for a skin test and appropriate treatment based on the cause.