April 30, 2026 Author : Tiago Marques Ribeiro (General and Family Medicine ) The most common form of transmission of scabies is direct skin contact with infected people. The parasite proliferates through the skin, triggering an intense allergic reaction with rashes and itching, because it lays eggs in the superficial layer of the skin. Treatment is done with antiparasitic medications, as well as other measures to stop transmission. Scabies is more frequent in overpopulated areas and tropical climates, but it exists worldwide and affects people of all ages. What is scabies and how is it transmitted? Scabies is a skin infection caused by a mite (a parasite). The mite Sarcoptes scabiei has several varieties and, in addition to humans, affects many species of domestic and non-domestic mammals. However, the variety of the parasite that affects humans, causing scabies, is Sarcoptes scabiei var. hominis . Pets do not transmit the parasite to humans because the varieties of mites that live in animals do not survive in humans. Scabies transmission is rapid and very easy. It occurs mainly when there is direct and prolonged contact with the skin of someone who is infected . Another, less frequent, form of transmission is through personal items and clothing, towels, and sheets. Thus, contagion is common among family members, sexual partners, or people who are present in the same space for extended periods, such as schools, homes, and others. An infected person can transmit scabies even without showing symptoms. Symptoms and diagnosis of scabies The period between contagion and the occurrence of symptoms varies: In people who have had the disease previously, symptoms appear in 3-4 days; In people who have never had the disease, symptoms may take longer to appear, about 3-6 weeks after contagion. The symptoms and signs of scabies are: Skin rash, with small vesicles and papules, as well as the appearance of fine and raised lines, usually reddish; They can be present in any area of the body, but are frequent in skin folds, such as between the fingers, wrists, armpits, and the navel area; Intense itching, which usually worsens at night (when the mites are more active), can interfere with sleep and is due to the inflammatory reaction. In infants and young children, the most commonly affected areas are: Fingers, palms of the hands, and soles of the feet; Scalp and face. In older children and adults, scabies is more common: Between the fingers and toes and on the soles of the feet; On the chest, nipples, waist, and navel; On the inner side of the wrists and elbows and in the armpits. In the genital area. The diagnosis of scabies is based on the history of complaints and clinical examination, particularly the typical distribution of skin lesions. Sometimes, in case of doubt, the doctor performs a skin scraping to observe under a microscope and try to identify the mites, eggs, or feces. Treatment of scabies The treatment of human scabies focuses on eliminating the mite and its eggs, requiring a rigorous approach both on the body and in the home environment. Medicines Scabies is treated with antiparasitic medicines , always as indicated and prescribed by a doctor. Creams, lotions, or ointments applied to the skin are most common. Treatment with oral medicines is also possible. These medications kill the mites and prevent the parasite from reproducing. Some do not kill the eggs, and this is one of the reasons why complete treatment requires more than one application or dose. In addition to antiparasitics, other medications may be necessary to relieve symptoms. The rash and itching do not disappear immediately. It can take up to 2-4 weeks after treatment for them to resolve. Treatment for scabies usually involves both the diagnosed person and those who live closely with them , whether or not they have symptoms. Treatment should be carried out exactly as directed by the doctor, even if symptoms improve or disappear before the expected end. Other treatment measures Scabies mites do not survive long away from human skin. However, there are additional measures that should be taken to interrupt transmission: Wash clothes, bedding, and towels in the washing machine at 60ºC; Dry in a dryer or in the sun; Ironing clothes can reinforce the effect of the temperature; For items that cannot be washed at the aforementioned temperature, opt for dry cleaning; Vacuum mattresses, sofas, carpets, and similar items thoroughly; Objects that cannot be washed or vacuumed should be sealed in a plastic bag for 5-7 days. This way, any mites present will not infest other people or survive. Prevention of scabies Scabies is prevented by avoiding direct and prolonged contact and not sharing clothes, household linens, and personal items with infected people. In case of contact or symptoms that may be related to scabies, medical attention should be sought. Early diagnosis and treatment prevent contagion and disease outbreaks. Frequently asked questions about scabies Meet the general and family medicine clinical team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
