Fingernail scratches can transmit diseases. While not every scratch leads to serious illness, understanding the risks is important. Fingernails harbor various microorganisms, and a break in the skin allows these microbes to enter the body.
Microbes on Fingernails
Fingernails, especially the area underneath, are not sterile. They harbor diverse microorganisms, including bacteria, fungi, and viruses. Studies identify species like Staphylococcus aureus, Streptococcus, and Candida albicans under nails. Longer nails provide more surface area for microbes to accumulate.
Nails regularly pick up and retain microbes from contact with surfaces and skin. Animal nails, particularly from cats, can carry pathogens like Bartonella henselae, the bacterium causing Cat Scratch Disease. This bacterium is often transmitted through flea feces contaminating a cat’s claws.
How Scratches Lead to Infection
The skin serves as a primary protective barrier, shielding the body from external threats. A fingernail scratch breaches this barrier, creating an opening for microorganisms to enter underlying tissues or the bloodstream.
Several factors influence the risk of infection. The depth and severity of the scratch play a role, as deeper wounds offer a more direct pathway for microbes. The cleanliness of the nail and the hygiene of the injured area significantly impact infection likelihood. An individual’s immune status also matters, with weakened immune systems increasing susceptibility to infection.
Common Diseases and Symptoms from Scratches
Fingernail scratches can cause various infections, from localized skin issues to systemic diseases. Common bacterial skin infections include cellulitis, characterized by hot, red, swollen skin, and impetigo, presenting as sores, crusts, or blisters. Both are often caused by Staphylococcus or Streptococcus bacteria.
Cat Scratch Disease (CSD) can develop after a scratch or bite from an infected cat, particularly kittens. Symptoms typically appear within 3 to 14 days, including a non-painful bump or blister at the scratch site, followed by painful, swollen lymph nodes. Other symptoms may include fatigue, headache, and fever.
Rarely, a deep scratch contaminated with soil or feces could pose a risk for tetanus, a serious bacterial infection affecting the nervous system. General signs of infection include increasing pain, spreading redness, swelling, pus or fluid from the wound, and fever.
When to Seek Medical Attention and Prevention
Prompt first aid minimizes infection risk from any fingernail scratch. This involves thoroughly cleaning the wound with soap and water, then applying an antiseptic. Covering the scratch with a clean bandage protects it from contamination.
Medical attention is necessary if signs of infection worsen. Deep scratches, especially from animals, or any scratch in individuals with compromised immune systems, warrant professional evaluation.
Preventing infections involves maintaining good nail hygiene, including keeping nails short and clean. Regular handwashing, with attention to cleaning under nails, reduces microbial load. Avoiding scratching others and practicing good hand hygiene are effective preventive measures.