History

Fact Explanation
Severe itching, worse at night. This is accompanied by skin lesions consisting of inflammatory cell infiltrates typical of a delayed type hypersensitivity immune reaction. [1]
Eruption of vesicles and papules. It is a consequence of both infestation and hypersensitivity to the mite. [2]
A history of itching in other members of the family. Transmission occurs through direct skin to skin contact. [3]
Uncommonly, non itchy crusted lesions. Present in immunocompromised patients (Norwegian scabies), It is highly contagious due to the massive colonies of mites. [4]
A history of topical or systemic steroid treatment. Patient develops scabies incognito, a condition with symptoms much like that in immunocompromised patients. [2]
In the infant and young child, the history suggests a more generalized rash, involving areas such as the head, neck, palms and soles. The parasite favors areas with a low concentration of pilosebaceous follicles and a thin stratum corneum. This seems to account for a difference in the distribution of the rash based on the age of the child, since this sort of skin is more widespread in the younger child. [5]
Infants and young children give a history of poor feeding and daytime sleepiness. The child is constantly restless and irritable due to the itching and at night time this results in poor sleep. [6]
References
  1. WALTON Shelley F. and Bart J. CURRIE. Problems in Diagnosing Scabies, a Global Disease in Human and Animal Populations. Clinical Microbiology Reviews. [online]. April 2007, vol. 20 no. 2 268-279. [viewed 3 March 2014]. Available from: doi: 10.1128/CMR.00042-06
  2. CHOSIDOW Olivier. Scabies. New England Journal of Medicine. [online].April 2006, 354:1718-1727. [viewed 3 March 2014]. Available from: DOI:10.1056/NEJMcp052784
  3. FITZGERALD Deirdre, Rachel GRAINGE and Alex REID. Interventions for preventing the spread of infestation in close contacts of people with scabies. Cochrane Database of Systematic Reviews [online]. 2014, Issue 2. Art. No.: CD009943.[viewed 3 March 2014] Available from: DOI: 10.1002/14651858.CD009943.pub2.
  4. PATEL, Anita, Peter HOGAN. and Brien WALDER. Crusted scabies in two immunocompromised children: Successful treatment with oral ivermectin. Australasian Journal of Dermatology [online]. 1999, 40: 37–40. [viewed 3 March 2014] Available from: doi: 10.1046/j.1440-0960.1999.00314.x
  5. HURWITZ Sidney. Scabies in Childhood. Pediatrics in Review [online] September 1979, Vol. 1(3) 91 -94 [viewed 5 March 2014]. Available from: doi: 10.1542/pir.1-3-91
  6. BARBARA G. et al. Transmission of Scabies in a Newborn Nursery. Infection Control and Hospital Epidemiology [online]. May 2011, Vol. 32,(5) : 516-517 [viewed 5 March 2014]. Available from: DOI: 10.1086/659954

Examination

Fact Explanation
Burrows, present as creeping, greyish lines. These are made by adult females as they digest and consume the epidermis. [1] Note: it is the classical diagnostic sign of scabies.
In infants, head, neck, palms and soles are involved with vesicles being most commonly found. There is a predisposition for vesicle formation in this age group. [2]
In older children, it involves the web spaces, flexures of arms and wrists, the axillae, etc. The parasite prefers areas of low concentration of sebaceous glands and thin stratum corneum. [2]
Scaly lesions in the skin, with associated lymphadenopathy. This is seen in Crusted (Norwegian) scabies; an entity that is most commonly associated with extreme incapacity and immunocompromised states. [3]
Golden crusted lesions (of impetigo), oozing lesions, etc. Due to secondary bacterial infection as a result of scratching. [4] This can lead to Glomerulonephritis and even acute rheumatic fever.
References
  1. McCARTHY J. S., et al. Scabies: more than just an irritation. Postgraduate Medical Journal [online] 2004 vol. 80: 382-387 [viewed 3 March 2014] Available from: doi:10.1136/pgmj.2003.014563
  2. KARTHIKEYAN Kaliaperumal. Scabies in children. ADC Education and Practice Edition [online] 2007, vol.92: ep65-ep69 [viewed 3 March 2014] Available from: doi:10.1136/adc.2005.073825
  3. STRONG Mark and Paul JOHNSTONE. Interventions for treating scabies. Cochrane Database of Systematic Reviews [online] 2007, Issue 3. Art. No.: CD000320. [viewed 3 March 2014] Available from: DOI: 10.1002/14651858.CD000320.pub2.
  4. FITZGERALD Deirdre, Rachel GRAINGE and Alex REID. Interventions for preventing the spread of infestation in close contacts of people with scabies. Cochrane Database of Systematic Reviews [online]. 2014, Issue 2. Art. No.: CD009943.[viewed 3 March 2014] Available from: DOI: 10.1002/14651858.CD009943.pub2.

Differential Diagnoses

Fact Explanation
Papular urticaria. This presents with recurrent pruritic papules or vesicles and varying degrees of local edema. [1]
Atopic dermatitis. Usually involves skin creases associated with redness, scaling, oozing, etc. [2]
Tinea corporis This presents as well demarcated annular plaques with scaly borders. [3]
References
  1. DEMAIN Geffrey G. Papular urticaria and things that bite in the night. Current Allergy and Asthma Reports [online]. 2003, Volume 3, Issue 4, pp 291-303. [viewed 4 March 2014]. Available from: DOI: 10.1007/s11882-003-0089-3
  2. ERSSER Steven J, et al. Psychological and educational interventions for atopic eczema in children. Cochrane Database of Systematic Reviews [online] 2014, Issue 1. Art. No.: CD004054 [viewed 4 March 2014]. Available from: DOI: 10.1002/14651858.CD004054.pub3.
  3. EL-GOHARY Magdy, et al. Topical antifungal treatments for tinea cruris and tinea corporis (Protocol). Cochrane Database of Systematic Reviews [online] 2012, Issue 8. Art. No.: CD009992.[viewed 4 March 2014]. Available from: DOI: 10.1002/14651858.CD009992.

Investigations - for Diagnosis

Fact Explanation
Multiple superficial skin scrapings, to be viewed under light microscopy. Definitive diagnosis relies on the identification of mites, eggs, egg shell fragments, etc. [1]
Dermatoscopy. Diagnosis is by observing the “jet-with-contrail” pattern in the skin representing a mite and its burrow. [2]
Burrow ink test. This depends on the burrows absorbing ink. [3]
Serological tests (specific IgE antibodies). Measuring levels of these antibodies to a major scabies antigen can help diagnose the disease with high sensitivity and specificity. [4]
References
  1. CHOSIDOW Olivier. Scabies. New England Journal of Medicine. [online].April 2006, 354:1718-1727. [viewed 3 March 2014]. Available from: DOI:10.1056/NEJMcp052784
  2. WALTON Shelley F. and Bart J. CURRIE. Problems in Diagnosing Scabies, a Global Disease in Human and Animal Populations. Clinical Microbiology Reviews. [online]. April 2007, vol. 20 no. 2 268-279. [viewed 3 March 2014]. Available from: doi: 10.1128/CMR.00042-06
  3. FITZGERALD Deirdre, Rachel GRAINGE and Alex REID. Interventions for preventing the spread of infestation in close contacts of people with scabies. Cochrane Database of Systematic Reviews [online]. 2014, Issue 2. Art. No.: CD009943.[viewed 3 March 2014] Available from: DOI: 10.1002/14651858.CD009943.pub2.
  4. JAYARAJ R., et al. A diagnostic test for scabies: IgE specificity for a recombinant allergen of Sarcoptes scabiei. Diagn microbiol infect dis. [online]. December 2011, (4): 403-7. [viewed 4 March 2014]. Available from: doi: 10.1016/j.diagmicrobio.2011.09.007

Investigations - Fitness for Management

Fact Explanation
Renal function tests. If there is secondary bacterial infection with group A Streptococcus, this could lead to acute glomerulonephritis and this could affect the pharmacological management. [1]
References
  1. STRONG Mark and Paul JOHNSTONE. Interventions for treating scabies. Cochrane Database of Systematic Reviews [online] 2007, Issue 3. Art. No.: CD000320. [viewed 3 March 2014] Available from: DOI: 10.1002/14651858.CD000320.pub2.

Management - General Measures

Fact Explanation
Treat close contacts of the index case as well as the index case both at the same time. Close contacts may act as reservoirs of infection; therefore treating them would prevent reinfection of the index case following successful treatment. [1]
Clothes and bed linen should be washed and dried the day after the first treatment. These items may harbor live mites. [2]
Ensure adequate nutrition. Malnutrition predisposes individuals to crusted scabies. [3]
Antihistamines and emollients. For symptomatic treatment of itch, including post-scabetic itch and itch caused by medication. [4]
Topical/ systemic antibiotics. When complicated by secondary bacterial infection. [4]
References
  1. FITZGERALD Deirdre, Rachel GRAINGE and Alex REID. Interventions for preventing the spread of infestation in close contacts of people with scabies. Cochrane Database of Systematic Reviews [online]. 2014, Issue 2. Art. No.: CD009943.[viewed 3 March 2014] Available from: DOI: 10.1002/14651858.CD009943.pub2.
  2. CHOSIDOW Olivier. Scabies. New England Journal of Medicine. [online].April 2006, 354:1718-1727. [viewed 3 March 2014]. Available from: DOI:10.1056/NEJMcp052784
  3. WALTON Shelley F. and Bart J. CURRIE. Problems in Diagnosing Scabies, a Global Disease in Human and Animal Populations. Clinical Microbiology Reviews. [online]. April 2007, vol. 20 no. 2 268-279. [viewed 3 March 2014]. Available from: doi: 10.1128/CMR.00042-06
  4. FITZGERALD Deirdre, Rachel GRAINGE and Alex REID. Interventions for preventing the spread of infestation in close contacts of people with scabies. Cochrane Database of Systematic Reviews [online]. 2014, Issue 2. Art. No.: CD009943.[viewed 3 March 2014] Available from: DOI: 10.1002/14651858.CD009943.pub2.

Management - Specific Treatments

Fact Explanation
5% permethrin topical application. Infants: Should be applied to the skin of the entire body including the scalp, forhead and sides of the head. Older children: Should be applied from the Jaw line downwards. It is safe and efficacious in infants and children. [1] (it is a pyrethroid that acts as an insecticide). In infants the head area is also affected. [2]
5-10% sulfur topical application. Infants: Should be applied to the skin of the entire body including the scalp, forhead and sides of the head. Older children: Should be applied from the Jaw line downwards. It is safe and efficacious in infants and children. [3]
Oral Ivermectin. It interrupts glutamate-induced and gamma-aminobutyric acid-induced neurotransmission in parasites, leading to their paralysis and death. [4] It is used to treat children with crusted scabies. [5]
1% Lindane- not used in children. It has a high potential for causing neurologic toxicity. [6]
References
  1. TAPLIN David, et al. Comparison of Crotamiton 10% Cream (Eurax) and Permethrin 5% Cream (Elimite) for the Treatment of Scabies in Children. Pediatric Dermatology [online]. 1990, vol 7: 67–73. [viewed 5 March 2014]. Available from: doi: 10.1111/j.1525-1470.1990.tb01078.x
  2. KARTHIKEYAN Kaliaperumal. Scabies in children. ADC Education and Practice Edition [online] 2007, vol.92: ep65-ep69 [viewed 3 March 2014] Available from: doi:10.1136/adc.2005.073825
  3. PRUKSACHATKUNAKORN C., M. DAMRONGSAK and S. Sinthupuan. Sulfur for Scabies Outbreaks in Orphanages. Pediatric Dermatology [online] 2002, 19: 448–453. [viewed 5 March 2014]. Available from: doi: 10.1046/j.1525-1470.2002.00205.x
  4. CHOSIDOW Olivier. Scabies. New England Journal of Medicine. [online].April 2006, 354:1718-1727. [viewed 3 March 2014]. Available from: DOI:10.1056/NEJMcp052784
  5. PATEL, Anita, Peter HOGAN. and Brien WALDER. Crusted scabies in two immunocompromised children: Successful treatment with oral ivermectin. Australasian Journal of Dermatology [online]. 1999, 40: 37–40. [viewed 5 March 2014] Available from: doi: 10.1046/j.1440-0960.1999.00314.x
  6. SCHULTZ Margaret W., et al. Comparative Study of 5% Permethrin Cream and 1% Lindane Lotion for the Treatment of Scabies. Arch Dermatol. [online]. 1990, 126(2):167-170. [viewed 5 March 2014]. Available from: doi:10.1001/archderm.1990.01670260037006.