[Toxic pictures produced spiders bites in Chile: latrodectism and loxoscelism]

Latrodectism, produced by the bite of Latrodectus spiders, is worldwide distributed, occurs in hot seasons, and affects mostly men when carrying out agricultural activities. The main symptoms are muscular pain and tremors, profuse perspiration, increased lacrimal, nasal and salival secretions, and hypertension. Symptoms last one week. Neostigmine is a very efficient drug in the treatment of this condition. Loxoscelism, caused by the bite of Loxosceles spiders, is worldwide distributed, affects individuals of all ages. It may present two clinical forms: cutaneous loxoscelism (CL) and viscerocutaneous loxoscelism (VCL). Both forms have been registered in all seasons, with a higher incidence in hot periods, and in bedrooms, when the person is sleeping or dressing. The cutaneous surface of limbs and face are most frequently affected. Local clinical manifestations are pain, edema and livedoid plaque, most of which evolve into a necrotic scar in CL, whereas hematuria, hemoglobinuria, jaundice, fever and sensorial involvement characterize VCL. If visceral involvement does not appear within 24 hours, it is probable that the diagnosis corresponds to CL, with a good prognosis. If a VCL patient survives 48 hours, the possibilities of recovery are high. The patients are successfully treated with parenteral antihistamines or corticosteroids in CL and corticosteroids in VCL.