Reaction types
Non-IgE-mediated reactions
Several blood-feeding Arachnida affect human health. Hemolytic and proteolytic enzymes in spider and scorpion venoms may have severe cytotoxic, neurotoxic or cardiotoxic effects142 and can cause acute generalized exanthematous pustulosis (AGEP),143-146 erythema multiforme147, and Drug Rash with Eosinophilia and Systemic Symptoms (DRESS).148 Ticks are generally known as vectors of bacterial infections (e.g. Lyme disease).Amblyomma tick bites may cause local annular erythema of unclear pathogenesis known as Southern tick-associated rash illness (STARI).149
Mite and ticks bites can provoke itching and local hypersensitivity reactions such as papular urticaria and vesiculopapular eruptions thought to be due to immune reactions to salivary proteins. Also “summer penile syndrome” in children, is considered to be an immunologic hypersensitivity reaction to chigger bites.150