Scabies produces a distinct set of signs you can look for: tiny raised, wavy lines on the skin (burrows), intense itching that gets worse at night, and a rash concentrated in specific body areas like the hands, wrists, and skin folds. The tricky part is that symptoms don’t appear until two to six weeks after you’re first infested, so by the time you notice something, the mites have been present for a while.
What Scabies Burrows Look Like
The single most distinctive sign of scabies is the burrow. These are tiny raised lines on the skin’s surface, created by a female mite tunneling just beneath the top layer of skin to lay eggs. They appear grayish or skin-colored, with a serpentine (S-shaped or wavy) pattern, and are roughly one centimeter long. On closer inspection, you may notice fine scaling along the surface of the line, and one end may have a slightly darker or raised spot, which is where the mite sits.
Burrows are not always easy to see. On lighter skin, they may look like faint pencil marks. On darker skin, they can be even harder to spot. Scratching can also obscure them, since broken skin and secondary irritation may cover up the original tracks. If you suspect scabies but can’t find burrows, that doesn’t rule it out.
Where to Look on the Body
Scabies mites prefer areas where the skin is thin and folds over itself. In adults, the most common locations are between the fingers, on the inner wrists, around the elbows, the waistline, around the navel, the buttocks, and the genitalia (especially in men, where firm reddish bumps on the penis or scrotum are a hallmark sign). The armpits and the sides of the feet are also common spots.
Infants and very young children are different. In babies, the rash often shows up on the head, face, neck, palms, and soles of the feet. These are locations that are almost never affected in adults, which can make scabies in infants look like a completely different condition.
The Nighttime Itch Pattern
Itching is the defining symptom of scabies, and it has a characteristic pattern: it gets significantly worse at night. One explanation is skin surface temperature. When you’re in bed under blankets and pajamas, your skin warms up, and this seems to intensify the itch. During warmer months, when people sleep with lighter covers or no covers at all, the nighttime worsening is less severe.
This pattern is useful for identification because many other itchy skin conditions don’t follow such a clear day-night cycle. If you find yourself scratching intensely every night but relatively comfortable during the day, scabies should be high on your list of suspects.
Why Symptoms Take Weeks to Appear
If you’ve never had scabies before, the incubation period is two to six weeks. During this time, you’re infested and can spread mites to others, but you feel nothing. The itching only begins once your immune system develops a sensitivity to the mites, their eggs, and their waste. This delayed reaction is why scabies can spread through a household before anyone realizes what’s happening.
If you’ve had scabies before, the timeline is very different. Your immune system already recognizes the mites, so symptoms typically appear within one to five days of re-exposure. This faster reaction can actually help with earlier identification the second time around.
The Burrow Ink Test
There’s a simple technique you can use at home to make burrows more visible. It’s called the burrow ink test. Rub fountain pen ink (or a washable felt-tip marker) gently over a suspicious area of skin. Then wipe away the excess ink with an alcohol swab. If a burrow is present, the ink seeps into the tunnel the mite has created and stays there, revealing a dark, wavy line even after the surface ink is removed. This test is often overlooked but can make the difference between guessing and knowing what you’re dealing with.
Scabies vs. Bed Bug Bites
Bed bug bites and scabies are commonly confused, but they differ in several key ways. Bed bug bites tend to appear on exposed skin, the parts of your body that aren’t covered by sheets while you sleep: arms, hands, neck, and legs. They usually show up as small red bumps, 2 to 5 millimeters across, arranged in lines or clusters. They’re itchy but don’t produce burrows.
Scabies, by contrast, favors hidden, folded areas of skin. The rash is concentrated between fingers, around the waist, and on the genitalia. The presence of burrows (those thin, wavy lines) is unique to scabies and won’t appear with bed bug bites. Bed bug bites also tend to be painless at first and appear overnight in a clear pattern, while scabies itching builds gradually over weeks.
Scabies vs. Eczema
Eczema and scabies can look similar on the surface, both cause red, itchy, inflamed skin. But eczema tends to appear in consistent locations based on your personal history (inner elbows, behind the knees, the face) and flares in response to triggers like dry air, soaps, or allergens. It doesn’t produce burrows, doesn’t concentrate between the fingers or on the genitalia, and doesn’t follow the dramatic nighttime-itch pattern that scabies does.
If you’ve been treating what you think is eczema for several weeks and it isn’t responding to moisturizers or over-the-counter steroid creams, especially if someone in your household has similar symptoms, scabies is worth considering.
Crusted Scabies Looks Different
There’s a severe variant called crusted scabies (previously known as Norwegian scabies) that looks nothing like the classic version. Instead of thin burrows and scattered bumps, it produces thick, crusty plaques on the skin that may crack and fissure. The typical rash and itch can be mild or completely absent, which makes it easy to mistake for psoriasis or severe dermatitis.
Crusted scabies is most common in elderly people, those with weakened immune systems (including people living with HIV), and people with conditions that prevent scratching, such as spinal cord injuries or paralysis. Because people with crusted scabies harbor thousands or even millions of mites (compared to the 10 to 15 mites in a typical case), they are extremely contagious.
How a Doctor Confirms the Diagnosis
A doctor can confirm scabies using a few different methods. The most definitive is a skin scraping: a very shallow scrape of the skin’s surface (done without anesthesia because it’s so superficial) placed on a slide with mineral oil and examined under a microscope. If mites, eggs, or their droppings are visible, the diagnosis is confirmed.
A faster and less invasive option is dermoscopy, which uses a handheld magnifying device pressed against the skin. Under dermoscopy, the mite’s head appears as a small dark triangle, sometimes described as looking like a “delta wing jet with a contrail,” the jet being the mite and the trail being the burrow behind it. Even when dermoscopy alone isn’t conclusive, it helps pinpoint exactly where to do a skin scraping for the best results.
Doctors use a standardized set of criteria to classify the diagnosis into three levels: confirmed (mites seen under microscope or imaging), clinical (visible burrows or typical lesions in typical locations combined with itch and known contact with an infested person), and suspected (typical-looking lesions with either itch or a contact history, but not both). You don’t need a confirmed mite sighting to be diagnosed and treated. Most cases are diagnosed clinically based on the combination of symptoms, rash location, and exposure history.