Cat scratch fever, cat allergy and rash: what to know

Cat-scratch disease can follow a scratch or bite and may cause a small bump at the injury, followed by tender swollen lymph nodes and fever. A cat allergy more often causes itching, hives, sneezing, a runny nose, or watery eyes after contact with dander, saliva, or fur. A rash limited to the scratch can also result from irritation or a skin infection such as cellulitis. Fever is not a typical feature of a simple allergy, so fever with worsening redness or swelling deserves medical assessment.

Wash a scratch or bite promptly with running water and soap, then keep the area clean and avoid picking at a scab. Note when the exposure happened, whether the cat was known and healthy, and how the rash or fever changes. For allergy symptoms, reduce contact with the suspected trigger, wash hands after touching the cat, and change clothes if symptoms follow close contact. Do not apply leftover antibiotics or steroid creams to broken skin without advice. A clinician can examine the wound, lymph nodes, and rash and decide whether testing or treatment is needed.

Arrange prompt medical care for a deep wound, a bite, spreading redness, increasing warmth, pus, severe pain, or fever after a scratch. Seek emergency help for trouble breathing, swelling of the lips or tongue, faintness, confusion, or rapidly worsening illness. Children, pregnant people, and anyone with a weakened immune system should seek advice sooner after an animal injury or unexplained fever.

Could this be an infected scratch, cat-scratch disease, an allergy, or another rash? Do I need treatment for the wound or swollen lymph nodes? Which changes should make me return urgently?