Is cellulitis very contagious?

No: Cellulitis is caused by bacteria entering thru a break in the skin. While it's not directly contagious, it is caused by bacteria on the surface of the skin which can be transferred from one person to another.

Catching cellulitis: To catch cellulitis, one has to have an open lesion or wound that would make it more susceptible to catch the infection or if there was an immune compromised individual or diabetic who can get easily infected due to their weaken state.

Whats the cause ?: Cellulitis is basically a visible inflammation (itis) of the skin and soft tissues (red, hot, swollen and tender) . It can be caused by many things including sunburn (radiation), trauma (sprained ankle) or poor vein circulation (stasis dermatitis). It need not be caused by bacteria. If you have repeated episodes of this, get to a wound care or vascular specialist, the diagnoses you have is wrong.