What should you know about oral antibiotics for a skin infection?

A clinician may consider oral treatment when bacteria have spread beyond a small area, the infection is deep, or local treatment is not enough. Cellulitis can cause expanding redness, warmth, swelling and tenderness, sometimes with fever. Similar-looking problems may be caused by viruses, fungi, irritation or allergy, and antibiotics will not treat those causes. The medicine selected depends on the suspected bacteria, infection site, allergies, other medicines and your health history.

Take the prescribed medicine exactly as directed and do not share leftover tablets. Ask how to take it with food, what to do after a missed dose and whether it interacts with your regular medicines. Keep the affected area clean, avoid squeezing it and follow dressing advice. Contact the prescriber if symptoms are not improving as expected or if side effects interfere with eating, drinking or daily activity. Diarrhoea, nausea and rash can occur; a severe or rapidly spreading rash needs urgent advice.

Get urgent help for rapidly spreading redness, severe pain out of proportion to the skin appearance, fever with weakness, red streaks, swelling near the eye, numbness, blistering or tissue turning dark. Call emergency services for facial or throat swelling, wheezing, collapse or difficulty breathing after a dose. These can indicate a serious infection or allergic reaction.

Does this look bacterial, and why is an oral antibiotic appropriate? How should I monitor the edge of the redness? What side effects need prompt attention? Do I need drainage, a swab, wound care or a follow-up examination?