The population that presents a high risk of developing this condition is made up of children and the elderly, especially those who live in overcrowded homes that favor the human-to-human transmission of the parasite through direct contact with a sick person. The prevalence of scabies is increased in populations living in tropical countries and affects both sexes equally.
In 2017, scabies was added to the list of under-addressed tropical diseases after a long period of documentation on the comorbidities associated with this condition and on the costs involved in treating patients who require hospitalization for the treatment of complicated forms of scabies.
content
Scabies – causes
The etiological agent of scabies is represented by a parasite called scabies Sarcoptes scabiei alternative of man. It penetrates deep into the skin, causing intense itching and specific scratching lesions, prone to bacterial superinfection.
The transmission of this parasite is favored by direct interpersonal contact and the intimate contact between the patient and the healthy host, and is easily achieved in groups of children from kindergartens and schools or in overcrowded conditions in hospitals, nursing homes, penitentiaries, refugee camps and shelters for the homeless.
Scabies symptoms
The cardinal symptom of scabies is represented by intense integumentary itching that occurs during the migration of the ectoparasite in the depth of the skin.
The lesions caused by scabies are typically located on the the wrists, fingers, in the periumbilical, buttock, perimamelonar area in women or in the genital area. The scalp is usually affected in infants and small children and less often in adults.
Skin changes specific to scabies are represented by vesicles, pustules, nodules and excoriation lesions.
Severe forms of the pathology associate the presence of specific crusts of the hyperkeratotic type (thickened skin with a scaly appearance without hair). Integumentary crusts associated with scabies represent a complication that occurs in untreated forms of the disease and presents a high risk of contagionbeing recognized by the characteristic appearance of scaly skin.
This complication is more common in children, the elderly, immunocompromised people (transplants under immunosuppressive treatment, patients undergoing corticosteroid treatment or associated with HIV infection) or with disabilities.
The discomfort caused by itching manifests itself especially during the night and constantly associates a decrease in the quantity and quality of the patient’s sleep, accompanied by the appearance of difficulty concentrating during the day and the decrease in school/professional performance with the impact on the quality of life in the long term.
Intense itching that is difficult to tolerate causes excessive scratching, which favors the formation of grillage lesions with an increased risk of bacterial superinfection. The continuity solutions generated at the skin level by excessive scratching favor the deep penetration of commensal or pathogenic germs from the surface of the skin, which generate specific pathologies such as impetigo, necrotizing fasciitis and, in severe cases, septic conditions.
In certain situations, infections caused by S aureus and S.pyogenes can trigger the appearance of an exacerbated immune response with the generation of antibodies directed against the body’s own structures of the type involved in acute rheumatic fever and post-streptococcal glomerulonephritis. These secondary complications of scabies are frequently encountered in the population of tropical and subtropical areas, currently it is estimated that approximately 40% of cases of impetigo are secondary to an infestation with scabies sarcoptus.
Apart from the listed clinical manifestations, scabies has a strong psychological, social and economic impact, affecting the patient’s quality of life through school/professional absenteeism, but also through the tendency of self-isolation and self-deprecation.
Types of scabies
From the point of view of clinical evolution, scabies can be divided into the following categories:
classical – recognized by the presence of the mite pit, pearly vesicles, pruritic vesicle papulo, grating lesions and urticarial plaques.
Incognita – atypical manifestation of scabies with modified distribution of lesions on the body surface, more frequently found in people who are under corticosteroid treatment.
Attenuated – found especially in patients with rigorous body hygiene, it is manifested by intense prurigo and is associated with minimal skin lesions.
hyperergic form it is represented by nodular scabies and is found in people who associate long evolution of the disease or after application of topical corticoids. This form of scabies is manifested by the appearance of red nodules with an infiltrated appearance, covered by hematic crusts after shaving.
Hypoanergic form:
Norwegian scabies found in multifarious people (who associate multiple pathologies) or in immunocompromised ones, but also in the case of those erroneously treated with dermatocorticoids.
Scabies in people with a competent immune system or those who live in endemic areas of Sarcoptes scabiei associates the existence of a limited number of ectoparasites that cause minimal clinical manifestations with self-limited evolution and the possibility of spontaneous healing.
Diagnostic scabie
The diagnosis of scabies is established by specialist dermatologist through the anamnesis and the detailed clinical examination of the patient.
Confirmation of the diagnosis of scabies it involves the identification of the ectoparasite (adult or immature form) that causes this condition, its eggs or excrement and involves skin tissue sampling for detailed microscopic analysis.
Dermoscopy or epiluminescent microscopy are non-invasive methods (does not involve the collection of skin tissue for examination) frequently used in dermatological practice to identify scabies sarcoptus infestation.
Videodermatoscopy uses a camera connected to a computer, with the help of which high-resolution images can be obtained in order to identify the parasite at the skin level.
Scabies treatment
After confirming the diagnosis of scabies, the treatment must be initiated both for the patient and for the contacts who live in the same residence as himto ensure the efficient eradication of the parasite and the prevention of subsequent reinfestations within the same family.
The first line of treatment for patients with scabies involves the use of of topicals (creams or lotions) while oral medication is reserved for cases of massive infestation with Sarcoptes scabiei difficult to treat.
Ivermectin administered orally, it is effective due to its ability to destroy parasites in adult form, but it cannot be administered during pregnancy or during breastfeeding.
In the case of children, ivermectin can only be administered if their weight exceeds 15 kg, but there are studies that support that this scabicide can be prescribed safely starting from the age of 1 month of the infant.
The scabicide it acts on the nervous and muscular system of the parasite and shows activity only on its mature forms capable of moving (larva, nymph and adult), but it cannot destroy Sarcoptes scabiei eggs.
Treatment of complicated forms of scabies that associate bacterial superinfection includes in most cases the administration of antibiotics, according to the sensitivity of the pathogenic germ to which they are addressed. Scabies with crust requires administration of oral treatment with scabicidesalong with which the repeated application of topical keratolytics with permethrin.
In general, the symptomatology due to infestation with Sarcoptes scabiei be remitted in 2-4 weeks from the initiation of topical treatment and scabicide, and the patient’s evolution is favorable in the long term. Multirapid patients, immunocompromised patients, children and the elderly with complicated forms of rabies may require a longer recovery period, especially when bacterial superinfections are associated with S.aureus or S,pyogenes.
Possible complications of scabies
The main complications of scabies are represented by the bacterial superinfection of skin lesions with pathogenic germs such as:
Streptococcus pyogenes (group A beta hemolytic streptococcus)
Staphylococcus aureus.
These bacteria can spread through the blood, causing nephritis, acute rheumatic fever or septic conditions with a poor prognosis.
The main measure to prevent the spread of the ectoparasite consists in isolating the patient who presents symptoms specific to scabies until he is completely cured. In addition, it is recommended to thoroughly sanitize the patient’s bedding and clothing and regularly ventilate the rooms to reduce the risk of transmitting the parasite to other family members.
References:
2023-07-10 22:03:31
#Scabies #symptoms #diagnosis #treatment
