Skin Health More Skin Conditions Scabies Guide Scabies Guide Overview Symptoms Causes Diagnosis Treatment Prevention How Scabies Is Diagnosed By Daniel More, MD Updated on April 16, 2024 Medically reviewed by Susan Bard, MD Print Table of Contents View All Table of Contents Self-Exam Visual Exam Microscopic Exam Ink Test PCR Test Skin Biopsy Other Causes Next in Scabies Guide How Scabies Is Treated Scabies is commonly diagnosed based on symptoms and exposure history. Lab tests sometimes confirm a scabies diagnosis or rule out other conditions. Most of the time, though, scabies' distinct symptoms (severe itching and rash) make diagnosing it reasonably simple on sight. Scabies can spread rapidly through a household through skin-to-skin contact (including sex) or infested furniture and linens. If one person has scabies, everyone should be treated. This article discusses scabies diagnosis. It explains how to test yourself for scabies at home and different tests your doctor may order before making a diagnosis. Illustration by Joshua Seong. © Verywell, 2018. How Can I Check Myself For Scabies? The first step in the diagnosis of scabies is recognizing it at home. If you notice any of the signs or symptoms of scabies, even without having known exposure to the infection, see your healthcare provider. Look for: Itching/Urge to Scratch: An intense itching sensation involves the chest, arms, hands, fingers, legs, breasts, or genital area. Rash: Small red bumps, nodules, or pimple-like irritations, which are most commonly located on the webbing between fingers, on the inner part of the wrist, under the arms, and on the elbows, knees, and along the belt line, can occur. Scabies does not usually affect the face and scalp. Burrows: Short zigzag or S-shaped lines or burrows, which appear as small tunnels, may occur. The parasite creates these tunnels as it settles in the body. Skin Wounds: Scratches, sores, and open wounds caused by excessive scratching or by a secondary bacterial infection may be present. Crusting: Thick, gray-colored skin crusts may be visible on your back, chest, feet, scalp, or other locations. This is a sign of a more advanced scabies infestation known as crusted or Norwegian scabies. The crusts contain hundreds to thousands of scabies mites and eggs. It may crumble easily when touched and does not have the intense itching commonly associated with scabies. Crusted scabies is more common in people with a weak immune system. Visual Exam Your healthcare provider may rely on their judgment of your signs and symptoms, your medical history, and your history of exposure to diagnose scabies. While scabies cannot be seen with the naked eye, your healthcare provider may use a special instrument called a dermatoscope to check for scabies. This device magnifies and illuminates skin, making it translucent, so mites and even their eggs are visible. If someone you're in close contact with has scabies, you may receive treatment even if you're not diagnosed with it. In some cases, your healthcare provider may order diagnostic tests to confirm scabies or rule out other conditions. Scabies Doctor Discussion Guide Get our printable guide for your next doctor's appointment to help you ask the right questions. Download PDF Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Email Address Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. Microscopic Examination The only way to be certain that your rash and itching are caused by scabies is to identify the mite itself. The rash that scabies induces is easy to see, but the actual scabies mite is very tiny and invisible to the naked eye. Your healthcare provider might place a drop of mineral oil on a burrow, take a scraping, and examine the sample under a microscope to look for the mites or their eggs. It is not always possible to see mites in a scraping; it depends on how many of them are present near the surface of your skin. Sometimes, scratching can destroy the burrow, making it more challenging to locate the mite on the skin. Diagnosing scabies with 100% certainty is not required for treatment. If you have Norwegian scabies, characterized by crusting on the surface of the skin, a large number of mites are normally present in the crusted areas. Ink Test A burrow ink test is a simple test that can be used to identify the burrow created by the scabies mite. The ink test is done by placing ink from a fountain pen on an area of skin with suspected scabies bites and burrows. The ink is wiped off the surface skin using alcohol. The ink test is considered positive if a wavy ink-filled line is visible below the skin surface, which indicates where the mite has tunneled. Polymerase Chain Reaction (PCR) Test A scraping of skin is used for the PCR test, an advanced genetic test that can identify material from even a small part of the parasite's body. This test, which has been used for other conditions, is only recently being studied for scabies. So far, PCR for scabies shows promise in research studies, but it is not widely available at this time. Skin Biopsy Sometimes a skin biopsy may be used to diagnose or confirm a diagnosis of scabies. This procedure involves examining a small sample of skin tissue under a microscope. A skin biopsy may show mites, eggs, larvae, or mite fecal matter. However, a skin biopsy is rarely necessary. It is often reserved for difficult or atypical cases. What Other Skin Conditions Could It Be? When scabies is misdiagnosed as another rash and untreated, the mite has a greater chance of spreading and affecting more people, as it can complete its life cycle and find new hosts. Scabies often looks like other itchy rashes, most of which are not contagious. These are the most common causes of a skin rash that looks like scabies: Allergies to medications or food can cause the development of a sudden rash, typically characterized by redness with small bumps or swelling. They are less commonly associated with a rash anywhere on the body, including the face. Contact dermatitis is a rash caused by a reaction to material touching the surface of the skin. Most of the time, contact dermatitis appears as a flat, red patch in the areas of the body that came into contact with the allergy-inducing material. Impetigo is a highly contagious bacterial skin infection. This can appear as clusters of open wounds, often with crusting. Eczema, a common rash that often appears without a known cause, is normally characterized by small, bumpy red spots, often with surrounding redness, which may be itchy. Psoriasis, an autoimmune condition that primarily affects the skin, is generally characterized by itchy, thick, light-colored flaky patches on the surface of the skin. How Scabies Is Treated 10 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Centers for Disease Control and Prevention. Scabies. Diagnosis Centers for Disease Control and Prevention. Scabies frequently asked questions (FAQs). Center for Disease Control and Prevention. Scabies. Disease American Academy of Dermatology. Scabies: signs and symptoms. Memorial Sloan Kettering Cancer Center. Scabies. Marghoob AA, Usatine RP, Jaimes N. Dermoscopy for the family physician. Am Fam Physician. 2013;88(7):441-450. Hardy M, Engelman D, Steer A. Scabies: A clinical update. Aust Fam Physician. 2017;46(5):264-268. Del Barrio-Díaz P, Vera-Kellet C. The Burrow Ink Test: a Simple Method to Improve the Diagnosis of Scabies. J Gen Intern Med. 2022. doi:10.1007/s11606-020-06522-6 Delaunay P, Hérissé AL, Hasseine L, et al. Scabies polymerase chain reaction with standardized dry swab sampling: an easy tool for cluster diagnosis of human scabies. Br J Dermatol. 2019; doi:+10.1111/bjd.18017 Siddig EE, Hay R. Laboratory-based diagnosis of scabies: a review of the current status. Transactions of The Royal Society of Tropical Medicine and Hygiene. 2022;116(1):4-9. doi:10.1093/trstmh/trab049 Additional Reading Hewitt KA, Nalabanda A, Cassell JA. Scabies outbreaks in residential care homes: factors associated with late recognition, burden and impact. A mixed methods study in England. Epidemiol Infect. 2015 May;143(7):1542-51. doi: 10.1017/S0950268814002143. Epub. Angelone-Alasaad S, Molinar Min A, Pasquetti M. et al. Universal conventional and real-time PCR diagnosis tools for Sarcoptes scabiei. Parasit Vectors. 2015 Nov 14;8:587. doi: 10.1186/s13071-015-1204-8. By Daniel More, MD Daniel More, MD, is a board-certified allergist and clinical immunologist. He is an assistant clinical professor at the University of California, San Francisco School of Medicine and formerly practiced at Central Coast Allergy and Asthma in Salinas, California. See Our Editorial Process Meet Our Medical Expert Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit