PAINE #PANCE Pearl – Dermatology



Question

 

What are the 5 things to assess in a suspicious lesion/mole to evaluate for melanoma?

 



Answer

 

The ABCDEs of melanoma will help you identify suspicious lesions that will need dermatologic follow-up

 

Asymmetry

  • Draw a line through the lesion and the two halves do not look similar, it is concerning

Border Irregularity

  • If the borders of the lesion are not uniform and smooth, it is concerning

Color

  • Different colors within the same lesion are concerning

Diameter

  • ≥ 6 mm is concerning

Evolution

  • Any lesion that changes in size, shape, color is concerning

 

The is also another set of criteria that was developed in the UK by the United Kingdom National Institute for Clinical Excellence (NICE) and by the Scottish Intercollegiate Guidelines Network called the Glasgow Seven-point Checklist.  These guidelines incorporate 3 major and 4 minor criteria and any major or 3 minor criteria is an indication for referral.

Major

  • Change in size or new lesion
  • Change in shape
  • Change in color

Minor

  • Diameter ≥ 7mm
  • Inflammation
  • Crusting or bleeding
  • Sensory change


Once a patient has been referred to a dermatologist, they use a similar seven point system on dermoscopy to diagnose melanoma.

Major (2 points each)

  • Atypical pigment network
  • Blue-whitish veil
  • Atypical vascular pattern

Minor (1 point each)

  • Irregular streaks
  • Irregular pigmentation
  • Irregular dots/globules
  • Regression structures

 

A melonoma score of ≥ 3 is required for diagnosis

 



References

  1. National Collaborating Centre for Cancer (UK). Melanoma: Assessment and Management. London: National Institute for Health and Care Excellence (UK); 2015
  2. Scottish Intercollegiate Guidelines Network. Cutaneous Melanoma. A national clinical guideline. January 2017.
  3. Argenziano G, Fabbrocini G, Carli P, De Giorgi V, Sammarco E, Delfino M. Epiluminescence microscopy for the diagnosis of doubtful melanocytic skin lesions. Comparison of the ABCD rule of dermatoscopy and a new 7-point checklist based on pattern analysis. Archives of dermatology. 1998; 134(12):1563-70. [pubmed]
  4. http://www.dermoscopy.org/consensus/2d.asp

Ep-PAINE-nym



Wood’s Lamp

 

Other Known Aliases – Ultraviolet (UV)-A lamp, blacklight

Definition – Handheld UV light that emits UV-A (long-wave) light with a violet filter, which blocks most of the visible light, and only allows the UV-A through

Image result for wood's lamp

 

Clinical Significance – There are many medical applications for using UV light for quick, bedside diagnosis.  One of these is for fungal infections of the skin, most commonly Tinea infections.  Tinea infections will fluoresce under UV-A light.

Image result for wood's lamp tinea

Tinea versicolor

Image result for wood's lamp tinea capitis

Tinea capitis

 

History – Named after Robert W. Wood (1868-1955), who was an American physicist, inventor, and a pioneer in infrared and ultraviolet photography.  In 1903, he developed a filter that would block visible light, but be transparent to both infrared and ultraviolet light.  He won several awards and honors in the field of optics (he even has a crater on the moon named after him) and is the namesake of the R.W. Wood Prize of the Optical Society of America, which recognizes outstanding discovery, achievement, or invention.

Robert Williams Wood.png


References

  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
  5. Ponka D, Baddar F. Wood lamp examination. Canadian family physician Medecin de famille canadien. 2012; 58(9):976. [pubmed]
  6. Ducharme EE, Silverberg NB. Selected applications of technology in the pediatric dermatology office. Seminars in cutaneous medicine and surgery. 2008; 27(1):94-100. [pubmed]

#25 – Scabies



***LISTEN TO THE PODCAST HERE***





Vector

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Sarcoptes scabiei

Scabies is caused by the mite Sarcoptes scabiei, which is a whitish-brown, eight-legged mite and it just barely visible by the naked eye at its largest size of 0.4×0.3mm.  Only the female mite causes the dermatologic manifestations seen in scabies, as it burrows into the epidermis down to the stratum granulosum layer to lay her eggs.

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The female mite can grow these burrows up to 2mm per day and lay 2-3 eggs, up to a total of 10-25 eggs.  These eggs hatch after 3-4 days, molt multiple times, and burrow to the surface to mate and then return to continue this viscous cycle.  Typically, incubation takes 3-6 weeks after infestations until symptoms present.


Transmission

Scabies are transmitted from direct contact with an infected person and most commonly is sexually acquired.  Although not as common, transmission has also been reported to occur through contaminated clothing or bedding as these mites can survive off a host for up to 24-36 hours.  Animals can contract scabies, but these rarely cause disease in humans, as they do not reproduce on human hosts.


Risk Factors

  • Colder temperatures
  • Higher humidity
  • Crowded areas with close contact

Signs and Symptoms

The typically manifestation of scabies is an intensely pruritic rash that is worse at night.  The lesions of the rash are small, erythematous, papules typically with an excoriated, hemorrhagic crust.  The burrows that may be seen are thin gray/brown/red lines up to 20mm in length.

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Areas most common infected are:screen-shot-2016-12-14-at-8-03-21-am

  • Webs of fingers
  • Flexor surface of wrist
  • Extensor surface of elbow
  • Axilliary folds
  • Peri-areolar
  • Periumbilical
  • Inguinal folds
  • Genital regions
  • Extensor surface of knees

 

Head, face, and back are not commonly seen and this is theorized to be due to the increased oil production in these areas.


Crusted (Norwegian) Scabies

Immunocomprimised, eldery, debilitated, or disabled patients are at increased risk of developing this severe form of scabies.  These mites are not more virulent, but because of their underlying medical conditions, the concentration of mites is much more numerous.  These patients develop thick crusts and are highly contagious due to the overwhelming contamination.

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Diagnosis

This should be a diagnosis of history and physical exam alone.  Skin scrapings can visualize the mites or eggs under the microscope.

Dermoscopy can be used to see the mite in burrow and is classically referred to as the “delta wing” sign, which is the dark head of the mite at the end of a burrow.

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“delta wing” sign


Treatment

  • Topical
    • Permethrin 5% cream
      • Apply from jaw line to the soles of feet
      • Leave overnight (8-14 hours) and washed off the next day
      • May be repeated 1-2 weeks later
      • Special populations
        • Category B in pregnancy
        • Safe in infants < 1 month
      • Crusted (Norwegian)
        • Daily application x 7 days, then 2x/wk until cured
  • Systemic
    • Ivermectin (3mg tabs)
      • 2 mg/kg single dose
        • Single dose not as effective as single application of permethrin
        • 2nd dose, 1 week later as effective as single application of permethrin
      • Recommended for large outbreaks, multiple infections in a single-household
      • Not recommended in pregnancy or children < 15kg
      • Crusted (Norwegian)
        • 2 mg/kg/dose given on day 1, 2, 8, 9, and 15
  •  Pruritus
    • Hydroxyzine 25mg q6hr
    • Mirtazapine 4.5-15mg qHS
    • Prednisone – 2-week taper starting at 60mg/day

Prevention of Re-infestation

Recommendations are for all close-contact household members to be treated simultaneously, even if asymptomatic, to prevent cross contamination and re-infestation.  Patients should be instructed to wash all clothing/bedding on the hot water cycle with high heat drying to kill any mites.  Stuffed animals, jackets, or any other objects not feasible to wash, can be isolated in a plastic bag for 3 days.  Fumigation is not necessary


References

  1. Romani L, Steer AC, Whitfeld MJ, Kaldor JM. Prevalence of scabies and impetigo worldwide: a systematic review. Lancet. Infectious diseases. 2015;15(8):960-7. [pubmed]
  2. Chosidow O. Clinical practices. Scabies. NEJM. 2006;354(16):1718-27. [pubmed]
  3. Heukelbach J, Feldmeier H. Scabies. Lancet. 2006;367(9524):1767-74. [pubmed]
  4. Johnston G, Sladden M. Scabies: diagnosis and treatment. BMJ. 2005;331(7517):619-22. [pubmed]
  5. Currie BJ, McCarthy JS. Permethrin and ivermectin for scabies. NEJM. 2010;362(8):717-25. [pubmed]
  6. Fuller LC. Epidemiology of scabies. Current Opinion in Infectious Diseases. 2013;26(2):123-6. [pubmed]
  7. Epidemiology and Risk Factors. Parasites – Scabies.  Centers for Disease Control.  Accessed December 14th, 2016. https://www.cdc.gov/parasites/scabies/epi.html
  8. Strong M, Johnstone P. Interventions for treating scabies. The Cochrane database of systematic reviews. 2007. [pubmed]
  9. Romani L, Whitfeld MJ, Koroivueta J. Mass Drug Administration for Scabies Control in a Population with Endemic Disease. NEJM. 2015;373(24):2305-13. [pubmed]
  10. Usha V, Gopalakrishnan Nair TV. A comparative study of oral ivermectin and topical permethrin cream in the treatment of scabies. Journal of the American Academy of Dermatology. 2000;42(2 Pt 1):236-40. [pubmed]
  11. Chambliss ML. Treating asymptomatic bodily contacts of patients with scabies. Archives of Family Medicine. 2000;9(5):473-4. [pubmed]