Scabies is a parasitic infestation caused by the microscopic mite, Sarcoptes scabiei, which burrows into the uppermost layer of the skin. While the infestation is not a direct cause of hair loss, the severe symptoms and secondary effects of a prolonged infection can trigger distinct forms of temporary hair loss.
Scabies: The Mite and Skin Reaction
Scabies begins when the pregnant female Sarcoptes scabiei mite tunnels into the stratum corneum, the outermost layer of the human epidermis. Once burrowed, the mite lays eggs and deposits fecal matter, which trigger the body’s reaction. This activity causes a delayed Type IV hypersensitivity reaction, leading to the hallmark symptoms.
The most noticeable symptom is intense pruritus, or severe itching, often worse at night and interrupting sleep. Physical signs include a pimple-like rash, tiny blisters, and fine, wavy, grayish-white lines representing the mites’ burrows. Mites commonly target skin folds and areas like the wrists, between the fingers, and the waistline. In infants and the immunocompromised, however, the infestation can be more widespread, sometimes affecting the scalp.
How Scabies Infestation Leads to Hair Loss
Hair loss associated with scabies is an indirect consequence resulting from the body’s response to the mites and intense irritation. One mechanism is mechanical trauma, where relentless, vigorous scratching damages the hair shaft. This physical action causes the hair to break off close to the scalp, localized to the areas of most intense itching.
Secondary bacterial infection is another factor, as scratching creates open sores and breaks in the skin barrier. Bacteria, such as Staphylococcus aureus, can enter these breaks and lead to a localized infection of the hair follicles, known as folliculitis. This inflammation often results in temporary, patchy hair shedding in the affected areas.
A third, more diffuse form of shedding is Telogen Effluvium, a temporary condition triggered by a physiological stressor. The chronic inflammation, severe sleep deprivation, and overall systemic stress from a prolonged scabies infestation can shock hair follicles prematurely into the resting (telogen) phase. This mass shift causes diffuse hair thinning and noticeable shedding, typically manifesting two to four months after the initial stress.
Diagnosis and Targeted Treatment of Scabies
A healthcare provider typically diagnoses scabies through a visual examination of the characteristic rash and burrow marks on the skin. To confirm the diagnosis, a simple skin scraping or ink test is performed to collect material from a suspected burrow. The collected material is then examined under a microscope to definitively identify the presence of mites, eggs, or fecal pellets.
Treatment focuses on the eradication of the mites using prescription topical or oral medication. The first-line topical treatment is often 5% permethrin cream, applied to the entire body from the neck down and washed off after 8 to 14 hours, usually with a repeat application one week later. Oral ivermectin is an alternative, especially for those who cannot comply with topical treatments or for cases of crusted scabies. Simultaneous treatment of all close contacts and thorough washing of clothing and bedding in hot water are necessary to prevent re-infestation.
Prognosis for Hair Regrowth
The hair loss resulting indirectly from a scabies infestation is generally not permanent. Once the mites are eradicated and the underlying skin inflammation and secondary infections are treated, the hair follicles begin to recover. Hair loss from mechanical trauma or localized folliculitis typically resolves as the skin heals and new hair growth resumes in the cleared areas.
Hair thinning caused by Telogen Effluvium is also a temporary condition, as the hair follicles are not permanently damaged. After the systemic stress of the infestation is removed, the hair cycle normalizes, and excessive shedding typically subsides within three to six months. Full hair density can take longer to return, often requiring several months of normal growth cycles to fully recover.