Scabies: Causes, Symptoms, Treatment & Prevention

Scabies is an intensely itchy dermatosis. It is a common contagious and deliberating infestation caused by the mite Sarcoptes scabiei. The infestation occurs at all ages but it is most common in children. Scabies is highly contagious and may spread fron one person to another via direct contact with the skin. Scabies is transmitted commonly by close personal contact. Therefore infants and children are most likely to get an infection. In adults, the transmission is usually by sexual contact. Transmission occurs because of close contact usually 15 minute skin-to-skin contact with the infected person.

What is the main cause of Scabies?

Scabies is mainly caused by the mite Sarcoptes scabiei. The female mite burrows into the epidermis and then lay eggs. Within a few days these eggs hatch into a larvae.

Signs and Symptoms

What are the main symptoms of Scabies?

The first symptom of itching occurs 2 weeks later after the infection when immune system reacts to the proteins in the mites, eggs and faeces. In immunocompetant individuals, during infestation the individuals can carry 10 adult mites, but in crusted scabbies the mite number increases to hundred due to the failure of host’s immune system. Pruritus is the main mark in scabies, regardless of age but in adults scabies is characterized by intractable pruritus and with lesions ion the web spaces. The most common lesions are papules, nodules, vesicles and pustules.

In men, itchy papules on the scrotum and and penis and these are pathognomonic. The pathognomonic sign is the burrow- a short, wavy, scaly grey blue line that appears on the skin surface. These burrows are mostly found on the

• Hands
• Feet
• Finger web spaces
• Thenar and Hypothenar eminences
• Wrist

What are the common infected sites in Scabies?

The most common sites are

• Fingers
• Finger webs
• Flexor surfaces of wrist
• Genital areas
• Elbows
• Ankle
• Feet and Nipples

Types of Scabies

What are the main types of Scabies?

There are two main types of Scabies

• Crusted Scabies
• Non- crusted Scabies

Crusted Scabies

In this type, patients have a crusted fine scaling on the skin which is superficial with little erthyema. Patients are usually old and immunosuppressed and do not complain of itching. Their immune system do not react against the mite proteins. Therefore number of mites are usually hundreds.

Non- crusted Scabies

In this type, the patient do not have a crusted scaling on the skin. Number of mites are few in number.

Scabies in children

Babies and young children infected with scabies are characteristically present with erythematous cutaneous papules and nodules in the arm region and on the soles of the feet. Classic burrows rarely be seen at this age.

Diagnosis and Treatment of Scabies

How to diagnose Scabies?

Scabies may be difficult to diagnose due vide variation in clinical presentations o the skin. As scabies may be confused with other skin rashes such as psoriasis ad eczema. Burrows can be seen in the finger web spaces and o the genitals. On the skin burrows are palpable ridges with a black speck indicating the position of the mite. These burrows can be teased out using a sterile needle and putted o the microscope slide. Patients of scabies have papular rash with multiple excoriation marks which become secondarily infected with bacterial cocci Staphylococcus.

Treatment of Scabies

Scabies can be treated by using scabicide(Permethrin/Melathion).

Antihistamines such as ceterizine or laratazine are also effective in the treatment of scabies.

Management of Scabies

How could we manage Scabies?

• First-line treatment for scabies is 5% Permethin(effective topical agent, well tolerated and has less toxicity)cream left o overnight. Adults should apply from neck to downward side while ifats should apply on all over the skin.
• 0.5% Melathion should be second choice and should be applied all over the body and left on overnight.
• Ivermectin 200ug/kg, two doses after a week can be given to the immnocompromised patients and patients with crusted scabies. It should be avoided in patients <15kg and in pregnancy.
• Allevation of pruritis can be seen with menthol in aqueous cream, crotamiton or doxepin. A topical steroid can also be used in severe case to settle persistent nodular skin reactions and it should be applied twice daily.
• 10% Sulphur in yellow soft paraffin is effective and safe if permethrin and melathion are not available.
• 25% Benzyl benzoate emulsification can also be used to treat scabies.  

 

Tags: Heath Care, Scabies, Skin Diseases, Treatment of Skin Diseases