Localized osteoporosis in Inflammatory disease

Localized osteoporosis often is the first (though nonspecific) radiographic manifestation of inflammatory diseases such as osteomyelitis, tuberculosis, and rheumatoid arthritis.
In pyogenic infections, bone destruction typically precedes osteoporosis, whereas in tuberculosis the reverse is true.
Periarticular demineralization is a classic early sign of rheumatoid arthritis.

Staphylococcal osteomyelitis. (A) Initial film of the first metatarsophalangeal joint shows soft-tissue swelling and periarticular demineralization due to hyperemia. (B) Several weeks later, there is severe bony destruction about the metatarsophalangeal joint.