Scabies is a contagious disease caused by Sarcoptes scabei hominis, a tiny mite—male being 0.2-0.15 mm and female 0.4-0.3 mm in measurement. They are whitish hemispherical mites having 4 pairs of very short legs.
Clinical Features
The main complaint is itching which is worse at night. Incubation period is usually 2-3 weeks.
Skin lesions of scabies can be of three types:
Lesions due to presence of mites are vesicles and burrows. Burrow is pathognomonic lesion which is ‘S’ shaped passage (5-15 mm), traversed by mite. It occurs most frequently on anterior aspect of wrists, the ulnar border of hand, interdigital webs, penis and palms and soles in infants. The vesicles are usually seen at the end of burrows.
Lesions due to allergic sensitivity are small urticarial papules, excoriation marks and rarely inflammatory nodules, usually seen on lower abdomen, the buttocks, the thighs and the scrotum.
Lesions due to complication can be pustular, impetiginous and eczematous. Rarely glomerulonephritis may complicate the pyoderma.
Other members of the family may also show similar manifestation. Sites of predilection are interdigital webs, the anterior aspect of wrist joint, the ulnar side of forearm, anterior fold of axillae, elbows, lower abdomen, penis and scrotum, around the nipples in women and palms, soles and scalp in infants.
Disease is commonly seen in children but can affect any age. It usually spreads by intimate contact. Overcrowding and poor hygiene also help in the spread of disease.
Treatment
Benzyl benzoate emulsion (25%), Gamma benzene hexachloride (1%), Monosulphiran (25%) and Crotomiton (10%) are commonly used in treatment of scabies. In children, crotomiton (10%) and half strength of 25% benzyl benzoate emulsion should be used.
After a scrub bath, medicine is applied all over body below neck. Next day again the patient is asked to apply the medicine without taking the bath and changing the clothes. On 3rd day patient is advised to take again a scrub bath followed by change of clothing. All the under-garments and bed linen should be laundered or washed in boiling water.
A single treatment is sufficient but a second treatment should be advised only after an interval of 7 days, if re-examination discloses definite evidence of persistent infection. All the contacts should be treated at the same time to prevent cross infection. Antihistamines should be given to control itching. Secondarily infected lesions should be treated with suitable antibiotics.
Norwegian Scabies
This form of scabies usually occurs in the mentally retarded and immuno-suppressed. This is characterized by asymptomatic hyperkeratotic and crusted lesions usually present over trunk, limbs, palms and soles. Such cases are highly contagious.
Pediculosis
Pediculosis is an infestation caused by lice. There are three distinct types of lice according to the area infested:
Pediculus humanus capitis (Head Louse)
Pediculus humanus corporis (Body Louse)
Phthirus pubis (Pubic Louse)
Pediculosis Capitis
It is caused by pediculus humanus capitis which is 3-4 mm in length and light brown in colour, usually prefers the scalp but may rarely live on beard and other hairy areas. It is transmitted by close contact or through combs or brushes. Poor personal hygiene is also an important predisposing factor. It is commonly seen in school children, especially those with long hair.
The patient complains of severe itching around the back and the sides of the scalp. Secondary bacterial infection, eczematization and regional lymphadenopathy are common complications. The diagnosis can be confirmed by the demonstration of adult lice or by presence of small white nits (eggs) firmly attached to a hair shaft.
Treatment
It consists of application of 25% benzyl benzoate emulsion, 1% Gamma benzene hexachloride or 0.5% malathion on to the scalp hair. Next morning, the hair should be washed with a shampoo or soap. Nits may be removed with a special fine toothed comb. Treatment should be repeated after a week so as to kill the lice that may have hatched out of the nits. Secondary infections and eczematization should be treated before specific therapy.
Pediculosis Corporis
Pediculosis corporis is caused by Pediculus humans corporis which is morphologically indistinguishable from head louse and its lives in the seams of the under clothes. It is commonly seen in individuals with grossly neglected poor hygiene and can be transmitted by close contact.
The patient will have severe itching with pinpoint macular or papular lesions, scratch marks, crusting and hyperpigmentation over the trunk and the shoulders.
Treatment
It consists of disinfection of clothes with 10% DDT, 1% Gammabenzene hexa-chloride or 0.5% malathion. Clothing may also be sterilized by boiling or by use of a hot iron especially over the seams.
Pediculosis Pubis
It is caused by Phthirus pubis, which usually inhabits the anogenital area, the axillae, the eyelashes and the eyebrows. Infestation is often transmitted by sexual contact or through formites.
It causes intense itching and later secondary infection and eczematization may occur. Bluish grey macule may be seen on the thighs, or lower abdomen. The nits are attached to the pubic hair or the hair of the regions mentioned.
Treatment
It is same as that of pediculosis capitis. Pediculosis of eyelashes can be treated by application of a one per cent ointment of yellow oxide of mercury.
Shopping Cart
