“Scabies.” I know that you are already itching. Soon it will be uncontrollable. The Ped EM Morsels have covered several conditions that cause pruritus (ex, Eczema, Tinea Capitis, Hyperbilrubinemia) as well as a general approach to Rashes, but nothing will make a patient, or a clinician, more uncomfortable than the potential for the patient having Scabies!
Scabies: The Ultimate Itch
- Scabies is a skin disease causes by infestation of a mite, Sarcoptes scabiei var. hominis.
- The mite burrows into the top layers of skin, where the female will lay her eggs.
- After 4-6 weeks, patients develop an allergic type reaction to the mite’s proteins and feces.
- Intense pruritus leads to problems!
- The itch leads to lots of scratching.
- Lots of scratching leads to mechanical injury to the skin.
- Skin injury allows for secondary bacterial infections (Staph and Strep) and complications:
- Suppurative complications
- Impetigo
- Cellulitis
- Subcutaneous abscesses
- Sepsis
- Non-Suppurative complications
- Acute post-streptococcal glomerulonephritis
- ~50% of acute post-strep GN in tropical settings is due to skin infection. [WHO]
- Rheumatic heart disease
- Scabies related skin infections offers an explanation of high rheumatic heart disease rates in countries with low rates of strep pharyngitis. [Parks, 2012]
- Acute post-streptococcal glomerulonephritis
- Suppurative complications
Scabies: Under-appreciated
- Scabies is more than a nuisance and control is a challenge. [Engelman, 2013]
- Scabies is one of the most prevalent skin conditions worldwide.
- 130 MILLION people have scabies at any one time worldwide. [WHO]
- Effects ~5-10% of children in developing countries.
- Effects people from every country, but is most prevalent in at risk populations:
- Populations with poor access to resources
- Young
- Elderly
Scabies: Different in Children
- Children may present with different clinical findings than adults.
- Infants are more likely to have: [Boralevi, 2014]
- Facial / Scalp involvement
- Palm and plantar lesions
- Dorsum of the forefoot lesions!
- Children (2-15 yrs) are more likely to have relapses. [Boralevi, 2014]
- Burrows are observed in all age groups, but not necessary for the diagnosis.
- Nodules also are seen in all age groups, but in infants more often in axilla and back locations.
- Look actively for burrows, axillary nodules and involvement in the soles, dorm of the forefoot, and scalp/face! [Boralevi, 2014]
Scabies: Treatments
- No treatment is perfect.
- Summarized nicely by Mousey and McCarthy [2013]
- Permethrin 5% Topical
- 1st line in many countries
- Good safety profile and effective
- Recommended to apply twice (2nd treatment 1 week after 1st treatment) to kill residual eggs that subsequently hatch.
- Limitation = expensive cost
- Benzyl Benzoate Topical
- Dosage: Adults – 25%; children 10-12.5%
- Highly efficacious
- Inexpensive
- Not available in the USA.
- Limitation = significant skin irritation that occurs immediately, limiting tolerance
- Ivermectin
- Off-label in most countries, but known to be effective.
- Oral
- Dose = 200 micrograms/kg; two doses, 2nd dose 1 week after 1st.
- Used to treat Crusted Scabies (high mite burden) and for treatment of large groups of patients.
- Not approved for kids < 15 kg or in pregnant / lactating women (who often have high burden of disease)
- Topical
- Dose = 1%
- More effective than single dose of oral.
- Other treatment considerations
- Antihistamines
- Avoidance of Lindane – less effective than other therapies and has adverse neurologic sequelae.
- Topical corticosteroids are not recommended as they may mask treatment failure.
- Treatment Failure:
- Challenging to determine as clinical pruritus will continue even after appropriate therapy.
- Most likely causes of treatment failure:
- Inadequate therapy or application of topical treatment
- Re-infestation (so consider treatment of contacts)
- Mite resistance (less likely than the 1st two).
References
Romani L1, Steer AC2, Whitfeld MJ3, Kaldor JM4. Prevalence of scabies and impetigo worldwide: a systematic review. Lancet Infect Dis. 2015 Aug;15(8):960-7. PMID: 26088526. [PubMed] [Read by QxMD]
Ahmad HM1, Abdel-Azim ES1, Abdel-Aziz RT1. Clinical efficacy and safety of topical versus oral ivermectin in treatment of uncomplicated scabies. Dermatol Ther. 2015 Nov 11. PMID: 26555785. [PubMed] [Read by QxMD]
Boralevi F1, Diallo A, Miquel J, Guerin-Moreau M, Bessis D, Chiavérini C, Plantin P, Hubiche T, Maruani A, Lassalle M, Boursault L, Ezzedine K; Groupe de Recherche Clinique en Dermatologie Pédiatrique. Clinical phenotype of scabies by age. Pediatrics. 2014 Apr;133(4):e910-6. PMID: 24685953. [PubMed] [Read by QxMD]
Chung SD1, Wang KH, Huang CC, Lin HC. Scabies increased the risk of chronic kidney disease: a 5-year follow-up study. J Eur Acad Dermatol Venereol. 2014 Mar;28(3):286-92. PMID: 23374101. [PubMed] [Read by QxMD]
Rosamilia LL1. Scabies. Semin Cutan Med Surg. 2014 Sep;33(3):106-9. PMID: 25577847. [PubMed] [Read by QxMD]
Engelman D1, Kiang K, Chosidow O, McCarthy J, Fuller C, Lammie P, Hay R, Steer A; Members Of The International Alliance For The Control Of Scabies. Toward the global control of human scabies: introducing the International Alliance for the Control of Scabies. PLoS Negl Trop Dis. 2013 Aug 8;7(8):e2167. PMID: 23951369. [PubMed] [Read by QxMD]
Mounsey KE1, McCarthy JS. Treatment and control of scabies. Curr Opin Infect Dis. 2013 Apr;26(2):133-9. PMID: 23438966. [PubMed] [Read by QxMD]
Parks T1, Smeesters PR, Steer AC. Streptococcal skin infection and rheumatic heart disease. Curr Opin Infect Dis. 2012 Apr;25(2):145-53. PMID: 22327467. [PubMed] [Read by QxMD]
Nolan K1, Kamrath J, Levitt J. Lindane toxicity: a comprehensive review of the medical literature. Pediatr Dermatol. 2012 Mar-Apr;29(2):141-6. PMID: 21995612. [PubMed] [Read by QxMD]
Bouvresse S1, Chosidow O. Scabies in healthcare settings. Curr Opin Infect Dis. 2010 Apr;23(2):111-8. PMID: 20075729. [PubMed] [Read by QxMD]
Diamantis SA1, Morrell DS, Burkhart CN. Pediatric infestations. Pediatr Ann. 2009 Jun;38(6):326-32. PMID: 19588676. [PubMed] [Read by QxMD]
Abedin S1, Narang M, Gandhi V, Narang S. Efficacy of permethrin cream and oral ivermectin in treatment of scabies. Indian J Pediatr. 2007 Oct;74(10):915-6. PMID: 17978449. [PubMed] [Read by QxMD]
Hengge UR1, Currie BJ, Jäger G, Lupi O, Schwartz RA. Scabies: a ubiquitous neglected skin disease. Lancet Infect Dis. 2006 Dec;6(12):769-79. PMID: 17123897. [PubMed] [Read by QxMD]
Heukelbach J1, Feldmeier H. Scabies. Lancet. 2006 May 27;367(9524):1767-74. PMID: 16731272. [PubMed] [Read by QxMD]
Raimer SS1. New and emerging therapies in pediatric dermatology. Dermatol Clin. 2000 Jan;18(1):73-8, viii. PMID: 10626113. [PubMed] [Read by QxMD]
The post Scabies appeared first on Pediatric EM Morsels.