"Inflammation" - what is it, definition of the term
The body's acute vascular and cellular reaction to tissue injury or invading agents, marked by erythema, increased temperature, edema, pain, and functional impairment, constitutes the inflammatory response; it is triggered by pathogens, mechanical damage, or chemical irritants, including bites from ticks, bugs, lice, and fleas, which introduce antigens and toxins that activate immune mediators and recruit leukocytes to the affected site.
Detailed information
The body’s vascular and cellular reaction to injury, infection, or foreign proteins is a rapid, organized process that aims to contain damage and initiate repair. Vascular changes include immediate dilation of small vessels, increased permeability, and exudation of plasma proteins into the interstitial space. Cellular components involve the recruitment of neutrophils, monocytes, and macrophages, guided by chemotactic signals such as interleukin‑8, complement fragments, and leukotrienes. These cells release proteolytic enzymes, reactive oxygen species, and cytokines that amplify the response and clear debris.
Observable manifestations comprise erythema, warmth, edema, tenderness, and reduced mobility. The intensity and duration of each sign depend on the nature of the stimulus, its location, and the host’s immune status. Acute phases are typically self‑limiting; chronic phases may lead to fibrosis or tissue remodeling.
When arthropods such as ticks, true bugs, lice, or fleas attach to the skin, they inject saliva or secretions that contain anticoagulants, proteases, and microbial antigens. These substances trigger the vascular and cellular reaction described above, producing localized swelling, itching, and sometimes necrosis. Tick attachment often yields a persistent, expanding nodule because saliva contains immunomodulatory proteins that delay resolution. Bug bites, especially from hematophagous species, generate immediate papular lesions with intense pruritus due to histamine release. Louse feeding causes recurrent papular urticaria, frequently on the torso and limbs, reflecting repeated exposure to salivary proteins. Flea bites appear as clustered, erythematous papules, commonly on the lower extremities, and may be accompanied by secondary bacterial infection if scratching breaks the skin barrier.
Effective management follows a stepwise approach:
- Remove the arthropod promptly; for ticks, use fine‑pointed tweezers to grasp the mouthparts and pull straight upward.
- Clean the bite site with mild antiseptic solution to reduce microbial load.
- Apply topical corticosteroid preparations to diminish edema and pruritus.
- Administer oral antihistamines for systemic itching or allergic component.
- Reserve systemic corticosteroids or antibiotics for extensive inflammation, secondary infection, or signs of systemic involvement.
Monitoring for delayed complications, such as pathogen transmission (e.g., Borrelia, Rickettsia) or chronic skin changes, is essential. Early intervention limits tissue damage and accelerates resolution.