Guide to California Ticks and How to Avoid Them

Another not-so-great outcome of global warming is that ticks are having a heyday. Yes, our least favorite insects (or are they mosquitos?) are digging the heat, so it’s good to be vigilant when outdoors.
This guide will give you an overview of ticks found in Southern California, some tips for avoiding them, and guidance for dealing with a bite. Even just writing this made me want to scratch my head, yuck.
California Ticks
In Southern California, several tick species can be found, some of which carry diseases. Ticks are becoming more common in California due to global warming and other environmental factors. Here are the main types of ticks in the region and the diseases they can transmit:
Western Black-legged Tick (Ixodes pacificus):

- Description: Small (2-3 mm when unfed), reddish-brown tick with dark brown to black scutum.
- Diseases Carried: Lyme disease, anaplasmosis
- Details: This tick is the primary vector of Lyme disease in California. It is commonly found in wooded, brushy areas and can attach to various hosts, including humans and pets.
American Dog Tick (Dermacentor variabilis)

- Description: Medium-sized (up to 6 mm unfed), reddish-brown tick with distinctive white markings on the dorsal shield
- Diseases Carried: Rocky Mountain spotted fever, tularemia
- Details: These ticks prefer grassy and brushy areas and are often found on dogs and other animals. They are capable of transmitting several diseases, though Rocky Mountain spotted fever is the most significant.
Pacific Coast Tick (Dermacentor occidentalis)

- Description: Medium-sized (up to 6 mm unfed), brown tick with light-colored mottling on the back
- Diseases Carried: Rocky Mountain spotted fever, tularemia, Colorado tick fever
- Details: Found in various habitats including grasslands, scrublands, and forests. This tick can transmit several diseases to humans.
Brown Dog Tick (Rhipicephalus sanguineus)

- Description: Small to medium-sized (3-4 mm unfed), reddish-brown tick that prefers warm environments and can be found indoors
- Diseases Carried: Canine ehrlichiosis, Rocky Mountain spotted fever (rarely to humans)
- Details: This tick prefers warm environments and is commonly found in and around homes and kennels. It primarily affects dogs but can occasionally bite humans.
Preventive Measures
- Avoid Tick Habitats: Stay on trails and avoid grassy, bushy areas where ticks are common.
- Use Repellents: Apply insect repellents that contain DEET on skin and permethrin on clothing.
- Check for Ticks: Regularly check yourself, children, and pets for ticks after spending time outdoors.
- Prompt Removal: If you find a tick, remove it promptly with tweezers, grasping it close to the skin and pulling it straight out.
- Color of clothing: The jury seems to be out on this one. Conventional wisdom was that light-colored clothing helped deter ticks, but evidence for this is sketchy.
What if You are Bitten?
If you are bitten by a tick, the Centers for Disease Control and Prevention suggest considering contacting your healthcare provider. The CDC generally does not recommend taking antibiotics after tick bites to prevent tick-borne diseases. However, in certain cases, a single dose of doxycycline may lower the risk of Lyme disease, especially in areas where Lyme disease is common.
Monitor for symptoms such as rash, fever, fatigue, headache, muscle pain, and joint swelling for 30 days. If any of these symptoms occur, call your healthcare provider. Treatment for tick-borne diseases should be based on symptoms, history of exposure, and sometimes blood test results, with most conditions being treatable with a short course of antibiotics.
Tick-borne Diseases in California
- Anaplasmosis
- Babesiosis
- Lyme Disease
- Spotted Fever Group Rickettsia and Rocky Mountain Spotted Fever
- Tick-Borne Relapsing Fever
- Tick Paralysis
- Tularemia