​Dermatology - Scabies

​Dermatology -  Scabies
Skin-to-skin contact and fomites are the two primary modes of transmission for scabies, which is an epidermal infection caused by the mite Sarcoptes scabiei var. hominis. It is possible for mites to survive on bedding or clothing for more than two days.

Patients are frequently aware of relatives or sexual partners who exhibit symptoms that are similar to their own.
Intense, widespread, and typically confined to the head and neck, pruritus frequently disrupts sleep and can be quite uncomfortable. It is possible for those who are prone to atopy to develop eczematous dermatitis, whereas other people may endure pruritus for a number of months without developing a rash. There is a possibility of secondary infection, which manifests itself as tenderness.


Hypersensitivity, lesions related to continuous rubbing and scratching, and subsequent infection are all examples of lesions that can develop at the site of an infestation. At the location of the infestation, there are skin-colored ridges that are linear or serpiginous and range in length from half a centimeter to one centimeter. At the end of the tunnel, there is a minute vesicle or papule. It is common for burrows to be found in locations where there are few or no hair follicles, typically in areas where the stratum corneum is thin and fragile. Examples of areas where burrows can be found include the interdigital webs of the hands, wrists, shaft of the penis, elbows, feet, buttocks, and axillae. Burrows can be as long as 10 centimeters. There may be nodules that range in diameter from 5 to 20 millimeters and are smooth, red, pink, tan, or brown in color. Forearms, thighs, buttocks, and anterior trunks are the most common locations for hypersensitivity reactions, which are characterized by the presence of tiny urticarial edematous papules. There is a possibility of postinflammatory hyperpigmentation and hypopigmentation.

Microscopy, if it is possible, is used to confirm the diagnosis, which is based on clinical examination and the finding of mites, eggs, or mite excrement. An unfavorable cutaneous medication reaction, atopic dermatitis, allergic contact dermatitis, metabolic pruritus, urticaria pigmentosa, papular urticaria, prurigo nodularis, and pseudolymphoma are all included in the differential diagnosis.


Regardless of whether or not symptoms are present, it is important to treat infected persons as well as close physical contacts at the same time. Either apply a 5% cream of permethrin from head to toe or a 1% lotion or cream of lindane (g-benzene hexachloride) to all regions of the body, beginning at the neck and working your way down. After eight hours, make sure to properly wash off the lindane. It is not recommended that individuals with significant dermatitis, pregnant or breastfeeding women, children younger than two years old, or those who have recently taken a bath or shower use lindane following these activities. There is evidence of mite resistance to lindane. Due to its low cost, lindane has become an important alternative in many nations. Crotamiton 10%, sulfur 2–10% in petrolatum, benzyl benzoate 10% and 25%, benzyl benzoate with sulfiram, malathion 0.5%, sulfram 25%, and ivermectin 0.8% are some other options that can be utilized. Intralesional triamcinolone, administered at a concentration of 5–10 mg/mL into each lesion, is useful in treating scabietic nodules. One dose of oral ivermectin at a concentration of 200 μg/kg is highly effective. (This product has not been approved by the FDA).