Cat Scratch Disease – Causes, Symptoms, Treatment

Cat scratch disease (CSD) is a bacterial infection transmitted by cats. It can be contracted through a scratch, lick  or bite of a cat and while cats are a carrier, they do not suffer from the disease themselves. The bite or scratch may not always be obvious and even a slight tear in the skin by an infected animal can result in cat scratch disease in humans.

Causes of Cat Scratch Disease

Bacterial infection caused by cats and kittens.

CSD is caused by a bacterium known as Bartonella henselae which is present in the saliva of the cat. Although you can pick up the disease through a scratch as well, it is important to remember that cats lick themselves constantly so the paw may contain saliva or the bacteria from the saliva.

Cat scratch is not contagious from person to person. While it is more common in children, this does not mean that other kids in the house or at school will contract the infection. In cases where more than one child in the same house is infected, it is usually due to the fact that these children were playing with the same carrier (cat).

Signs and Symptoms of CSD

The signs and symptoms of cat scratch disease are vague. It appears like the flu but there is a noticeable swelling of the lymph nodes. These swollen lymph nodes are usually painful. Sometimes a small rash is present that looks like an insect or mosquito bite but other than this, it is not easy to spot CSD immediately.

A history of being exposed to cats or kittens as well as the swollen lymph nodes around the area of the bite or scratch is the most noticeable symptoms. Other groups of lymph nodes like those of the armpit, groin and neck may also become swollen even if the bite or scratch is not in this area. In cases where the cat may have licked the eyes, the infected person may also present with conjunctivitis (‘pink eye).

Other symptoms are similar to those associated with the flu (seasonal influenza) and includes a fever, general feeling of being unwell, lethargy and fatigue, headaches, body pains and a loss of appetite.

If a person is bitten or scratched, it takes between 4 to 7 days for a small bump to appear at the site if the event that the cat was a carrier of the bacteria Within a week or two, the swelling of the lymph nodes will become apparent. This swelling should settle within 2 to 3 months.


Once the doctor confirms CSD, the infected person will be prescribed antibiotics, like doxycycline. If a lymph node is very swollen, hard and painful, your doctor may have to drain it. CSD is not a serious infection and within a few weeks to months, the infected person will fully recover from it. However HIV/AIDS patients should be cautious as this illness, like any infection, can cause serious complications in patients with a low CD4 count.