What should you know about spider bite cellulitis treatment?

Cellulitis affects deeper layers of skin and may begin where scratching, a blister, or a small wound has damaged the skin barrier. Skin redness, tenderness, warmth, and swelling can spread beyond the original mark. A bite may be the suspected starting point, but the appearance does not prove which insect was involved. Athlete's foot, diabetes, or another break in the skin can increase the need for careful assessment.

A clinician may prescribe an antibiotic when cellulitis is diagnosed and will choose the medicine according to the examination and your health history. Take it exactly as directed and complete the prescribed course unless the prescriber changes it. Rest the affected area when practical, keep the skin clean, and mark the edge of redness so changes are easier to describe. Do not squeeze a lump or use leftover antibiotics.

Get same-day medical advice for spreading redness, worsening pain, fever, or increasing swelling. Seek emergency help for confusion, severe weakness, fast breathing, fainting, or rapidly worsening illness because these can signal a serious infection such as sepsis. People with diabetes or weakened immunity should seek advice early rather than waiting for the area to settle.

How can you tell whether this is cellulitis or a bite reaction? Which treatment do I need, and when should improvement begin? What changes mean the infection is spreading?