University of Alabama at Birmingham 2013 Case #10 Universidad Peruana Cayetano Heredia

This is our last case of the week for 2013.  We hope you have enjoyed the 2013 series of live cases each week from Perú.  The Gorgas Diploma Course is held annually in February and March and we will be in touch at the beginning of next year’s case series.

The following patient was seen by the Gorgas Advanced Course participants in the outpatient department of the Tropical Medicine Institute.

Image AB for 08/19/2013History:  57-year-old previously healthy female presented with a one-year history of cutaneous lesions beginning on the fingers and toes that then extended to the foot, ankle, abdomen and arms.  The lesions were non-tender, associated with nocturnal itching, and uniformly became covered with a non-necrotic crust.  No odor, exudate or discharge.  No other symptoms.  She received steroids and other topical treatments from several physicians with no improvement.

Epidemiology:  Born and lives in Lima, but lived in the Amazon for several months several years ago.  Her parents are of Quechua origin (highlands of Perú).  No alcohol, illicit drug or tobacco use.  No known TB exposure.  She had three pregnancies, with a history of blood transfusion during one delivery.  Husband is healthy.  Her father died in a car accident and her mother died with cervical cancer.  She used an IUD for 10 years.

Physical Examination:  Afebrile.  No hepatosplenomegaly; no lymphadenompathy.  Normal lungs, heart and abdomen.  Normal neurologic exam.  Abnormalities restricted to >30 skin lesions (examples shown in Images A & B) over the fingers, toes, foot, ankle, abdomen and arms.

Laboratory Results:  Hematocrit 43%.  WBC 7,800 with 0% bands, 72% neutrophils, 20% lymphs and 2% eosinphils.  Biochemistry unremarkable with glucose 88 and Cr 0.9.
Diagnosis:  Crusted Scabies (Norwegian scabies).  HTLV-1 infection.

Image CD for 08/19/2013Discussion:  Skin scrapings viewed by direct microscopy disclosed 2-3 Sarcoptes scabei per each high power field [Image C] – a remarkable density.  Skin biopsy showed mites in the epidermis [Image D] together with scybala (hardened masses of feces).  Typically crusted scabies is a hyperkeratotic psoriasiform dermatitis with eggs, larvae, and adult mites abundant in the cornified layer.  ELISA and Western blot for HTLV-1 were both positive in the patient.  Testing of the mother, siblings, and children is being pursued.  The patient breastfed but also has a history of blood transfusion.

The crusted, diffuse, highly pruritic skin lesions in this patient are very characteristic for Norwegian scabies.  This condition is well described in many immunocompromising conditions including HIV infection, malignancy and immunosuppressive therapy.  The skin is hyperinfested with thousands of mites, so it is easily diagnosable with simple scrapings.  The lesions are highly infectious and present a serious nosocomial risk.

At the Tropical Medicine Institute in Lima approximately 70% of all cases of Norwegian scabies are associated with HTLV-1 infection and are, in the absence of any other factors, associated with immunosuppression.  Other opportunists associated with HTLV-1 are strongyloides infection (negative Baermann stool concentration in our patient), onychomycosis and acute infectious dermatitis of childhood [see Gorgas Case 2004-07].  Similar to HIV, several recent cross-sectional studies have found a high prevalence of HTLV-1 among tuberculosis patients and a high prevalence of tuberculosis among HTLV-1-infected people.  TB mortality may be increased in the face of HTLV-1 infection.

Other conditions associated with HTLV-1 infection [see Lancet Infect Dis. 2007 Apr;7(4):266-81 for a detailed discussion] are acute T-cell leukemia/lymphoma [see Gorgas Case 2011-07] and autoimmune disease including tropical spastic paraparesis, Sjogrens, arthropathy, polymyositis, and thyroiditis.  This patient did not have any neurological findings.

The prevalence of HTLV-1 in South America is generally underappreciated, normally being associated with Japanese and Caribbean populations.  HTLV-1 is now known to occur worldwide, having originated in Africa.  The highest prevalence is in Japan.  In Perú, the disease is highly endemic (2-3% seropositivity) in Andean areas of the country in Quechua populations who have had no contact with Japanese immigrants to the country.  Other South American countries with significant rates of HTLV-1 include Brazil, Colombia, and Ecuador.  Transmission appears to be mainly vertical with high associations with breastfeeding and duration of breastfeeding.  Transfusion, sexual transmission and IV drug abuse are much less important.

Norwegian scabies is not responsive to normal topical agents such as benzyl benzoate or permethrin.  Our patient was treated with ivermectin 200 µg/kg bid for 2 days which was repeated 15 days later.  The lesions responded dramatically to therapy.

Most individuals with HTLV-1 infection remain asymptomatic for life.  For those with complications there are few treatment options for the underlying HTLV-1 infection.  Trials with anti-retroviral agents and immunomodulators have been uniformly unsuccessful.