Merck Manual

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Tick Bites

By

Robert A. Barish

, MD, MBA, University of Illinois at Chicago;


Thomas Arnold

, MD, Department of Emergency Medicine, LSU Health Sciences Center Shreveport

Reviewed/Revised Jun 2022 | Modified Sep 2022
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Ticks, like mites, are closely related to spiders. These small creatures, sometimes carried as parasites on the bodies of humans and animals, may transmit disease to humans.

The bites of pajaroello ticks, which are present in Mexico and the southwestern United States, produce pus-filled blisters that break, leaving open sores that develop thick black scabs (eschars).

Most tick bites do not transmit disease and are painless. However, they often cause a red bump and itching at the site of the bite and may cause allergic skin reactions in some people.

Tick paralysis

In North America, some tick species secrete a toxin in their saliva that causes tick paralysis. A person with tick paralysis feels weak and fatigued. Some people become restless, weak, and irritable. After a few days, a progressive paralysis develops, usually moving up from the legs. The muscles that control breathing also may become paralyzed.

Treatment of Tick Bites

  • Removal of tick

  • Application of antiseptic

  • Sometimes an antibiotic by mouth to prevent Lyme disease

Tick bites can sometimes be prevented by taking precautions in areas where ticks are common.

Preventing Tick Bites

People can reduce their chances of picking up or being bitten by a tick by doing the following:

  • Staying on paths and trails when walking in wooded areas

  • Walking in the center of trails to avoid brushing up against bushes and weeds

  • Not sitting on the ground or on stone walls

  • Wearing long-sleeved shirts

  • Wearing long pants and tucking them into boots or socks

  • Wearing light-colored clothing, which makes ticks easier to see

  • Applying an insect repellent containing diethyltoluamide (DEET) to the skin

  • Applying an insect repellent containing permethrin to clothing or wearing clothing commercially pretreated with permethrin

Usually, Lyme disease is transmitted by young deer ticks (nymphs), which are very small, much smaller than dog ticks. So people who may have been exposed to ticks should check the whole body very carefully, especially hairy areas, every day. Inspection is effective because ticks must be attached usually for more than a day and a half to transmit Lyme disease.

To remove a tick, people should use fine-pointed tweezers to grasp the tick by the head or mouthparts right where it enters the skin and should gradually pull the tick straight off. The tick's body should not be grasped or squeezed. Petroleum jelly, alcohol, lit matches, or any other irritants should not be used.

Deer ticks

Tick removal should be done as soon as possible. Removal is best accomplished by grasping the tick with curved tweezers as close to the skin as possible and pulling it directly out. The tick’s head, which may not come out with the body, should be removed, because it can cause prolonged inflammation. Most of the folk methods of removing a tick, such as applying alcohol, fingernail polish, or petroleum jelly or using a hot match, are ineffective and may cause skin damage or cause the tick to expel infected saliva into the bite site.

Did You Know...

  • The best way to remove a tick is with tweezers, directly pulling it off.

After the tick is removed, an antiseptic should be applied. If swelling and discoloration are present, an oral antihistamine may be helpful. If the tick appears to have been attached for an extended period (the tick is very swollen) or Lyme disease is prevalent in the area, doctors may give an antibiotic to help prevent Lyme disease.

If a tick bite, such a pajaroello tick bite, causes significant skin damage, the doctor extensively cleans and removes any dead skin from the wound. The doctor may apply corticosteroids and antiseptics to the area to prevent further skin damage and infection.

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