A 40 y.o. woman comes to the ED with abdominal pain and dark urine. She is found to be severely anemic. A lesion was noted on her torso.

Hint: there were no RBCs in the urine, no signs of blood loss and elevated LDH

She had cutaneous-hemolytic loxoscelism.  

the violin on the body and three pairs of eyes are characteristic of the brown recluse

Typically,  envenomation results in a localized cutaneous response with development of a blister that turns purple and then black in 24 hours.  In one out of ten patients a more systemic reaction occurs.  In 7-10 days,  fever, jaundice, abdominal pain, vomiting and a generalized rash can occur.  In the unlucky few,  acute hemolysis and renal failure occur. 

The venom of a brown recluse spider  contains enzymes like sphinogomyelinase D that triggers the immune system to attack RBCs. There is both a direct toxic effect of the venom and  complement-mediated immune destruction of red blood cells. In this case the bite itself was the key to the diagnosis because there are many causes of hemolytic anemia.

HEMOLYTIC ANEMIA

INTRINSIC CAUSES

Hemoglobinopathies- sickle cell, thalassemia

Enzyme deficiencies- G6PD

Red cell membrane defects- spherocytosis

hereditary spherocytosis is sometimes only diagnosed in adulthood.

EXTRINSIC/ACQUIRED

Infections-malaria, Rocky Mountain spotted fever, H. flu,  HIV.

Drugs- Penicillin, sulfonamides, quinine

Autoimmune hemolytic anemia(AHA)- can only be considered if all other causes are ruled out. It  can occur with autoimmune disorders and cancer. AHA is divided into warm which occurs at body temperature and is IgG antibodies  and cold which appears when exposed to cold and is IgM antibodies. Mycoplasma bacteria share similar antigens with the “I antigen “ on RBCs  causing a hemolytic anemia.

Toxins- venomous snakes, spiders and bees can cause hemolysis.  Heavy metals are also implicated.  Lead, copper, zinc and arsine gas have all been reported to cause hemolysis.

Our patient recovered after receiving  two units of packed cells and steroids.   Below is the chart of another patient who recovered more slowly.

FUN FACT

South Carolina is the only state with an officially designated state spider.  It is the Carolina Wolf spider shown below.  It’s eyes glow brightly under a flashlight at night

wolf spider bites are like bee stings

Harry S, Brugioni E, Madhusudhana S. Acute hemolytic anemia caused by loxoscelism treated with plasmapheresis:a case report. J Med Cases 2022 Apr 23;`2(5):219-224.

Abraham M, Tilzer L, Hoehn KS, Thornton SL. Therapeutic plasma exchange for refractory hemolysis after brown recluse spider (Loxosceles reclusa) envenomation. J Med Toxicol. 2015;11(3):364–367.

Kaur D. Acute haemolytic anaemia secondary to lead poisoning: a case report. Cureus 2026Feb 5;18(2)e103043.

Widen J, Jonsson G, Karlsson U.  Mycoplasma pneumonia with severe cold agglutinin hemolysis, thrombocytosis, leukemoid reaction and acute renal failure. IDCases. 2023 Jan 13;31:e01689.