Scabies is a common skin condition caused by an infestation of Sarcoptes scabiei mites. These mites penetrate the upper layer of the skin, where they live and lay their eggs. The presence of these mites triggers an immune response in the body, leading to a rash and intense itching. Because its symptoms can closely resemble those of many other dermatological issues, scabies is frequently misidentified, making accurate self-diagnosis quite challenging.
Understanding Scabies Symptoms
The most distinctive symptom of scabies is intense itching, which often becomes more severe at night or after a hot bath or shower. This itching is due to an allergic reaction to the mites, their eggs, and their waste products.
Alongside the itching, a pimple-like rash appears, consisting of small red bumps or blisters. These lesions commonly occur in areas where the mites prefer to burrow, such as the webbing between the fingers, wrists, elbows, armpits, and around the waist, nipples, or genitals. Burrows are also present, appearing as tiny, raised, winding lines on the skin surface that are grayish-white or skin-colored. These burrows can be difficult to spot. If a person has never had scabies before, symptoms can take anywhere from two to eight weeks to appear after initial exposure.
Conditions Often Confused with Scabies
The similar appearance of rashes and shared symptom of itching mean several other skin conditions are often mistaken for scabies. Eczema, for instance, is a skin inflammation that can cause red, inflamed, and intensely itchy skin. While both can present with redness and small blisters, eczema is a chronic inflammatory condition not caused by mites and is not contagious.
Insect bites from sources like mosquitoes, bed bugs, or fleas can also produce itchy, red bumps that might be confused with scabies lesions. However, unlike scabies mites that burrow into the skin, bed bugs feed on the skin surface and then retreat to hiding places. Bed bug bites often appear in clusters or a zigzag pattern on exposed skin, whereas scabies rashes tend to spread across the body and include burrow marks.
Folliculitis, an infection and inflammation of hair follicles, can lead to small, red bumps or pustules that resemble scabies papules. A key difference is that folliculitis often lacks the intense, nocturnal itching characteristic of scabies. While both present with bumps, the itch associated with folliculitis is less severe or absent.
Impetigo, a highly contagious bacterial skin infection, causes red sores or blisters that rupture and form yellowish-brown crusts. This condition is common in children and can be mistaken for scabies due to similar rash appearances. However, impetigo is caused by bacteria, not mites, and its sores cause only mild itching, if any.
Allergic reactions or hives (urticaria) can result in widespread itchy welts or rashes that might be confused with a scabies rash. Hives are an allergic response to an allergen, medication, or stress, characterized by raised, itchy welts that can appear anywhere on the body and often come and go rapidly. Scabies, conversely, is a persistent infestation with a specific distribution pattern.
Distinguishing Features and Professional Diagnosis
Several factors can help differentiate scabies from other skin conditions. The intense itching of scabies, which worsens significantly at night, is a strong indicator. The presence of characteristic burrows—tiny, raised, winding lines—is another distinguishing feature, commonly found between the fingers, on the wrists, or in other skin folds. While other conditions might cause itching or bumps, the combination of severe nocturnal itching and visible burrows points more specifically to scabies.
The distribution of the rash also provides clues; in adults, scabies affects areas like finger webs, wrists, elbows, armpits, genitals, and buttocks, while sparing the face and scalp. However, in infants and young children, the rash can appear on the head, face, neck, palms, and soles of the feet. Given the similarities in symptoms across various skin conditions, self-diagnosis of scabies is unreliable. Seeking a professional medical diagnosis from a doctor or dermatologist is important for accurate identification. A healthcare provider can diagnose scabies based on a physical examination and patient history, and may confirm the diagnosis by taking a skin scraping to examine for mites, eggs, or fecal matter under a microscope.