Scabies Overview and Treatment

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Questions and Answers

Which topical scabicide is considered the treatment of choice and is safe for infants and pregnant women?

Crotamiton 10%

Ivermectin 1% solution

Gamma benzene hexachloride 1%

Permethrin 5% (correct)

What is a common side effect of treatment that can cause persistent itching after scabies therapy?

Acarophobia (correct)

Severe allergic reaction

Reinfection (correct)

Nodular scabies (correct)

Which systemic treatment for scabies requires a single dose based on weight?

Benzyl benzoate

Malathion

Permethrin

Oral Ivermectin (correct)

What distinguishing feature characterizes lice as the causative agents of pediculosis?

Their nits are attached firmly to hair shafts. Signup and view all the answers

Which is NOT a common site for pediculosis capitis?

Armpits Signup and view all the answers

What is one significant disadvantage of using sulfur as a scabicide?

It can cause skin irritation Signup and view all the answers

What is the primary method of transmission for pediculosis capitis?

Direct contact Signup and view all the answers

What is the recommended treatment for nodular scabies?

Intralesional steroid injection Signup and view all the answers

What is the primary cause of scabies?

A mite Signup and view all the answers

Which of the following is a characteristic lesion of scabies?

Burrows Signup and view all the answers

Where are scabies lesions typically distributed on the body?

On the dorsa of hands and feet Signup and view all the answers

What symptom is most commonly associated with scabies?

Severe itching Signup and view all the answers

How does scabies primarily spread?

Direct contact with infected individuals Signup and view all the answers

What is a significant difference between human classic scabies and animal scabies?

Lesions in animal scabies do not have burrows Signup and view all the answers

Which of the following areas is typically free from scabies lesions?

The face Signup and view all the answers

In infants and young children, where are scabies lesions often found?

On the scalp and face Signup and view all the answers

What is a characteristic feature of prurigo of Hebra?

Superficial lymphadenopathy Signup and view all the answers

Which of the following criteria is NOT a major criterion for atopic dermatitis?

Presence of peripheral edema Signup and view all the answers

In a case of suspected scabies, where should the classic examination focus be?

Webs of fingers and flexure aspects of wrist joints Signup and view all the answers

What is the primary lesion associated with scabies?

Burrows Signup and view all the answers

What is the common cause of papular urticaria?

Insect bites Signup and view all the answers

What is the preferred antibacterial for treating pediculosis capitis due to its additional pediculicide effect?

Co-trimoxazole Signup and view all the answers

What is the typical duration for wheals associated with acute urticaria?

1 to 48 hours Signup and view all the answers

What must be done after applying topical pediculicide lotion to the hair?

Wash the hair after 12 hours Signup and view all the answers

Which of the following is NOT a characteristic of urethria?

Presence of nits on hair Signup and view all the answers

Which of the following is NOT a recognized type of urticaria?

Dermatitis Signup and view all the answers

Which condition is commonly associated with angioedema?

Wheals Signup and view all the answers

Which type of lice is considered sexually transmitted and primarily affects young adults?

Crab lice Signup and view all the answers

What is a common characteristic that distinguishes urticaria from other skin lesions?

Wheals may fade and new lesions can appear Signup and view all the answers

What is the purpose of using white vinegar in the treatment of pediculosis?

To dissolve the cement that holds nits to the hair Signup and view all the answers

What is the primary treatment for urticaria?

Antihistamines Signup and view all the answers

What can trigger urticaria apart from allergic reactions?

Direct stimuli on mast cells Signup and view all the answers

Papular urticaria is most frequently seen in which age group?

Infants and children Signup and view all the answers

What is the ideal dosing of oral Ivermectin for treating pediculosis capitis?

0.2-0.4 mg/kg as a single dose repeated after 8 days Signup and view all the answers

In chronic urticaria, how long do the symptoms typically persist?

More than 6 weeks Signup and view all the answers

Which of the following foods is a common trigger for urticaria?

Strawberries Signup and view all the answers

Which of the following is NOT a symptom associated with urticaria?

High fever Signup and view all the answers

Study Notes

Scabies

Highly contagious skin condition caused by a mite, Sarcoptes scabiei.
Transmission:
- Direct contact with infected individual.
- Indirect contact through contaminated items like towels or bedding.
Incubation period: 2 weeks to 2 months.
Characteristic lesion: Burrows, appearing as small lines on the skin, typically seen early in infection.
Symptoms:
- Intense itching, especially at night.
- Other lesions include papules, vesicles, and crusting.
- Distribution: Commonly found on the hands, wrists, elbows, axillae, abdomen, genitalia, and lower limbs.
Types:
- Human classic scabies: The most common type.
- Animal scabies: Transmitted from animals to humans.
- Scabies in infants: Atypical distribution, affecting the scalp, face, and soles.

Treatment of Scabies

Topical scabicides:
- Permethrin 5% (treatment of choice): Apply twice, 24 hours apart. Safe in infants and pregnant women.
- Crotamiton 10%: Apply twice, 24 hours apart.
- Benzyl benzoate 25%: Apply twice, 24 hours apart.
- Sulfur 10% (adults) / 3-5% (infants): Apply every night for four nights. Safe in infants, children, and pregnant women.
- Gamma benzene hexachloride 1%: Apply once for 12 hours. Not recommended for infants, children, pregnant or lactating women, or those with seizures.
- Malathion 0.5%: Apply for 12 hours, then wash off.
- Ivermectin 1% solution: Apply for 12 hours, then wash off. Repeat after a week.
Systemic scabicides:
- Oral Ivermectin: Effective against scabies. Dose: 6 mg/15 kg (0.2-0.4 mg/kg). Repeat after one or two weeks. Not recommended for children under 15 kg, pregnant or breastfeeding individuals.
Additional treatment:
- Antihistamines for itching.
- Antibiotics for bacterial infections.

Nodular Scabies

Treatment:
- Intralesional steroid injection.
- Surgical excision.

Causes of Persistent Itching After Scabies Treatment

Hypersensitivity to mite antigens.
Reinfection.
Unsuccessful treatment.
Irritation from scabicides.
Acarophobia (fear of mites).

Pediculosis (Lice)

Def: Infestation with lice, small blood-sucking parasites.
Life cycle:
- Females lay eggs (nits) that attach to the hair shaft.
- Nits hatch within a week.

Pediculosis Capitis (Head Lice)

Site: Scalp, primarily above the ears and occiput.
Transmission: Direct contact or sharing hats, combs, and brushes.
Symptoms:
- Itching.
- Nits visible on the hair shaft.
- Possible impetigo and cervical lymphadenopathy.

Treatment of Pediculosis Capitis

Step 1: Treat bacterial infections if present (e.g., impetigo) with systemic antibiotics.
Step 2: Apply topical pediculicides after controlling bacterial infection:
- Malathion 0.5%, Ivermectin 1%, or Permethrin 5%.
- Apply to clean, dry hair for 12 hours, then wash off.
- Repeat treatment after one week to ensure eradication.
Nit removal:
- Apply a vinegar solution (equal parts white vinegar and water) to loosen the glue holding nits to the hair.
- Wash after 1-2 hours and comb hair with a fine-toothed comb to remove nits.
- Oral Ivermectin: Alternative treatment, 0.2-0.4 mg/kg single dose, repeated after 8 days.

Pediculosis Pubis (Crab Lice)

Transmission: Sexually transmitted.
Site: Pubic and perineal hair. Can also affect eyelashes.
Symptoms:
- Intense itching.
- Lice firmly attached to the base of hairs.

Urticaria (Hives)

Def: Acute skin condition characterized by wheals (raised, red, itchy bumps).
Causes:
- Allergic reactions (e.g., food, drugs, pollen).
- Non-allergic reactions (e.g., physical factors, infections).
Symptoms:
- Sudden appearance of itchy wheals that last for hours to 48 hours.
- Wheals can be localized or generalized, ranging in size from small to large.
Associated conditions:
- Angioedema: Swelling in the skin and subcutaneous tissue (face, lips, genitalia).
- General symptoms: Nausea, vomiting, dysphagia, hoarseness, wheezing, dyspnea.
Types:
- Acute urticaria: Symptoms last for less than 6 weeks.
- Chronic urticaria: Symptoms last longer than 6 weeks.
Special types:
- Angioedema
- Dermographism
- Cold urticaria
- Aquagenic urticaria
- Cholinergic urticaria
- Solar urticaria
- Contact urticaria
- Serum sickness

Treatment of Urticaria

Primary focus: Identifying and removing the triggering cause.
Medications:
- Antihistamines: Primary treatment.
- Systemic steroids: Adjuvant treatment for severe cases.
- Adrenaline, calcium gluconate (in severe, life-threatening cases).

Papular Urticaria (Prurigo Simplex)

Def: Hypersensitivity reaction to insect bites (e.g., fleas, mosquitos).
Symptoms:
- Occurs mostly in infants and children.
- Itchy red papules (1-5 mm).
- Lesions located primarily on the limbs; occasionally on the trunk.
Course:
- Often subsides spontaneously, even with continued exposure to insects.
- Desensitization to insect antigens may occur over time.
Prurigo of Hebra (Atopic prurigo):
- Persistent form of papular urticaria, especially in individuals with atopic dermatitis (eczema).
- Characterized by numerous, lichenified (thickened) lesions, excoriated papules, and superficial lymphadenopathy.

Atopic Dermatitis (Eczema)

Diagnosis: Four major criteria should be present.
- Pruritis (itching)
- Typical morphology and distribution for age group.
- Chronic or chronically relapsing dermatitis.
- Personal or family history of atopy (allergies, asthma, eczema).

Treatment of Atopic Dermatitis

General measures:
- Environment modifications.
- Avoid triggers (e.g., irritating clothing, skin products, allergens).
Medications:
- Oral antihistamines.
- Short-course systemic steroids for extensive cases.
- Topical soothing lotions or corticosteroids.

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Description

This quiz provides essential information about scabies, a highly contagious skin condition caused by the mite Sarcoptes scabiei. Explore its transmission methods, symptoms, and effective treatments, including topical scabicides. Test your knowledge on scabies types and management strategies.