A 85 y.o. woman comes from a nursing home after a fall. She has a small scalp laceration and co her palms itching.
What could be wrong?
Our patient had Norwegian scabies ( also called crusted scabies) .
Norwegian scabies is a severe contagious form of scabies that can be life threatening. The mites in this disease breed prodigiously and often 2 million are burrowing under the skin. By comparison most people who get scabies have 15-29 mites on their skin.
The mites can be seen on skin scrapings either on a wet mount or KOH
It is called Norwegian scabies because it was first described in Norway by Danielssen and Boeck. They were studying leprosy in leprosariums where Norway had been isolating lepers since the 15th century . In 1839 they produced the first study linking leprosy to Mycobacterium leprae. It wasn’t until 2017 when a study showed that a molecule called PGL-1 which sits on the surface of M leprae reprograms macrophages( helper T cells) to overproduce nitric oxide which interferes with the mitochondrial repair system of cells. The helper T cells are no longer able to activate cytokines and destroy invading bacteria.
Although altered immunity was found to be a reason for mite proliferation in leprosy; altered immunity in the elderly, those with HIV or those receiving chemo, make these groups more susceptible to Norwegian scabies as well. Norwegian scabies can be fatal because of skin breakdown and bacterial infection.
Psoriasis, shown above, HIV, syphilis and leprosy can all present with rupiod plaques.
FUN FACTS
Why was there leprosy in Norway in the 1800’s? It was though to have been introduced to Norway by Viking raders returning from Ireland and Great Britain where it was prevalent in the 10th century. It was originally described in India 4,000 years ago. By the 15th century leprosy had disappeared from Europe because of strict isolation and improvement in living conditions as well as the rise of tuberculosis which was similar enough to M. leprae to provide immunity.
In 1873 the bacillus causing leprosy was first discoved by Armauer Hansen before mycobacterium tuberculosis was discovered.
Nine banded armadillos are the only mammals other than humans that can carry Mycobacterium leprae which cause leprosy. They are reponsible for the rise of cases of leprosy in the southeastern US.
Antibody for PGL-I indicates infection with leprosy but does not necessariy mean disease.
Our patient was given ivermectin in the ED and followed by derm who repeated the ivermectin and added permethrin and topical steroids. She continues to have pruritus.
Ashraf R, Tarun N, Kumaran M. Lepromatous leprosy with crusted scabies. Am J trop Med Hyg. 2020 Dec;103(6):2158-2159.
Espy P, Jolly H. Norwegian scabies occurrence in a patient undergoing immunosuppression.
Niode N,Adji A, Gazpers S, et al. Crusted scabies, a neglected tropical disease: case series and literaturre review. Infect Dis Rp 2022 Jun; 1493):479-491.