What Are the Symptoms of an Allergic Reaction to a Bite?

A local or systemic allergic reaction that occurs when an insect bites the skin. Those with mild symptoms have no obvious symptoms, and those with severe symptoms may experience severe life-threatening allergic reactions.

Basic Information

Visiting department: dermatology
Common causes: Caused by insect bites on the skin

Common symptoms: Pruritic edema erythema
Contagious: no

Causes of bug bites

The disease is related to insect bites, such as bed bugs, fleas, lice, mites, and mosquitoes. When arthropods bite the skin, their saliva and other secretions cause skin irritation or allergic reactions and cause disease.

Clinical manifestations of insect bites

Local insect reactions, papules, urticaria, or systemic allergic reactions can occur after insect bites.

Local reaction

Caused by various substances in insect saliva that irritate the skin. It usually appears within a few minutes after the bite and manifests as a local pruritic edema erythema that usually resolves within hours.

2. Pimple urticaria

It is a late-type allergic reaction that occurs after insects bite the skin. It is clinically characterized by wind-like skin lesions with severe itching. It is mainly seen in children 2 to 10 years old. The rash occurs in exposed areas such as the extremities of the limbs, clusters or scattered. A typical rash is a spindle-shaped red wind-like pimples of the size of mung beans to peanuts, often with small blisters on the top, and tense bullae may also appear. The rash is often accompanied by severe itching, which affects sleep. Secondary infections can occur after scratching. The rash can resolve in about 1 to 2 weeks, leaving a temporary pigmentation. However, new rashes often occur one after another to prolong the course of the disease, and old and new rashes often coexist.

3. Systemic allergic reaction

A small number of patients (especially those with mastocytosis) can have severe systemic allergic reactions after insect bites, which are manifested as edema erythema or wind masses throughout the body, edema of the throat, and anaphylactic shock.

Diagnosis of insect bites

The rash is characterized by pruritic edema, erythematous erythema, or wind-like pimples. Need to identify with urticaria, erysipelas, chickenpox, bullous pemphigoid and so on.

Insect bite response treatment

Local treatment

Immediately after the insect bites were found, clean the skin of the bite with soap and water, and apply cold boiled lotion or magnesium sulfate to the erythematous erythema and apply 1% calamine menthol brain lotion; papular urticaria to strong glucocortic Hormone cream for external use.

2. Systemic treatment

Anti-histamines are given orally, such as cetirizine, loratadine, and cyproheptadine, as appropriate, based on the rash and itching level. For those with significant edema, glucocorticoids can be applied in a short-term system. Patients with systemic allergic reactions should immediately be given subcutaneous or intramuscular injection of epinephrine and systemic application of glucocorticoids.