Asthma attacks can make people feel as if they are suffocating. As they struggle to draw breath through narrowed airways in their lungs, they inhale in short gasps and exhale in long, noisy wheezes. The lower ribcage may contract sharply on inhaled breaths, and the pulse races; in a severe asthma attack, the sufferer’s lips may turn blue from loss of oxygen.

Experts still aren’t sure why cartilage, the shock-absorbing tissue that normally coats the ends of bones, sometimes breaks down. When it does, it causes those typical arthritis symptoms: stiffness and pain.