Cutaneous Larva Migrans

Since Liz said that her dog was going through a hookworm infection , this was the next logical post! Cutaneous larva migrans (CLMs) are what happens when worms get into us that don't want to be in us. This can happen especially often with Ancylostoma braziliense, which is the hookworm that most often infects dogs and cats.

                                                      Photo Credit: cdc.gov

Ancylostoma braziliense really would rather be in a dogs intestinal system. However, the mode of transmission is the same - adult worms lay eggs in the small intestine that get passed out, the eggs hatch and mature over 1-3 weeks in the soil (which is why hookworms are most prevalent in moist areas - if the eggs dry out they die), and then the infective larva wriggle their way into the circulatory system of whoever steps on them. The worms are hoping this is a dog!

However, when humans step on the area where infected dogs went to the bathroom a few weeks ago, they are at risk for getting the larva too. Fortunately for the humans (but unfortunately for the baby larva), they don't know what to do when faced with a human internal system. This causes them to stay close to the surface of the skin, and flail around in confusion.

What that means is that people will present with lines on their skin that look like someone colored on them with a red marker. It will start off as a bump that perhaps looks like a mosquito bite. Over the next few weeks, the bump will spread outwards in a long and winding line, which will eventually become dry and itchy. Typically the line will progress 1-2mm per day. While it's most common to show up on the feet, it can also be present in any area where bare skin made contact with the ground - since the infection is quite common on beaches, this can mean these lines showing up on any areas people were trying to tan! Moral of this story : wear shoes and put down a towel when you sunbathe.

While it might be tempting to try and "dig out" the worm yourself, don't! The red line does not show up for several hours after the worm has moved on. Also, it's microscopic.

Best treatments for this condition are typical anti-helminth drugs (thiabendazole), or a topical solution containing an anti-helminthic drug.

                                          Photo Credit: Stanford.edu
                   

                                               Photo Credit: Infectionnet.org

These are both pretty mild cases, you can easily see the path of a single wandering worm in each! Luckily, this is rarely a bad problem, as it is very visible and easily treatable, and the worm stays fairly close to the skin surface.