One of the best dandruff treatments out there will only run you $4

When you’ve got flakes on your scalp, figuring out what to do about them can often feel like solving a puzzle. First, you need to determine what they are and why they’re happening, and only then can you come up with a plan to nix ‘em. There are many different reasons why your scalp could be flaking, and in the latest episode of Dear Derm, board-certified dermatologist Mona Gohara breaks down each and every one and how to deal with them.

The biggie? Dandruff, which is characterized by an overgrowth of yeast called malassezia furfur. All of us are born with some of this stuff naturally occurring in our bodies,  but if we start to produce too much of it it can cause a disruption in the microbiome, and show itself by way of flakes and a greasy, stinky scalp.

To combat dandruff, Dr. Gohara suggests looking for products with selenium sulfide, salicylic acid, and zinc pyrithione. One of the best options out there will only run you $3. “If you’re in the drugstore, pick up some Head and Shoulders,” says Dr. Gohara. “The active ingredient, pyrithione zinc, is a good defense against malessezia furfur—aka the yeast that drives the dandruff bus.” She notes that if you’ve got dandruff, you should be washing your hair more frequently, and a few good lather and rinse sessions should help do the trick of getting rid of it.

If the OTC stuff isn’t cutting it, you’ll probably want to book an appointment with a dermatologist, who will likely recommend an anti-yeast shampoo or an anti-inflammatory like a topical steroid to ditch this fungus. “It may be a combination of a medicated shampoo and a topical steroid that you leave on your scalp,” says Dr. Gohara. “In some situations, it also might be helpful to increase the number of times per week that you wash your hair.”

With all of that in mind, it’s worth noting that seborrheic dermatitis is only one of a number of different things that could be causing a light white dusting on top of your head—and every cause requires a slightly different treatment. To find out how to determine what type of flake situation you’re dealing with, and how best to deal with it, press play on the video above.

Dandruff can also happen in your eyebrows—here’s what to do to deal. Plus, the essential oils you can use to help with any and all flakes on your scalp.