What does flea bite allergy look like? - briefly
Flea bite allergy typically manifests as clusters of tiny, red, raised welts with intense itching, most often on the lower legs, ankles, or feet. Lesions may develop a central punctum, swell, and sometimes form a surrounding halo of erythema.
What does flea bite allergy look like? - in detail
Flea bite allergy manifests primarily as skin lesions that develop shortly after exposure. The lesions are typically small, raised, red papules ranging from 2 mm to 5 mm in diameter. Central puncture marks or tiny dark dots often indicate the bite site. Intense pruritus accompanies the rash; scratching can enlarge the lesions and produce secondary erosions.
Common characteristics include:
- Clusters of papules concentrated on the lower extremities, especially around the ankles, calves, and feet.
- Swelling of the surrounding tissue, which may produce a well‑defined wheal.
- Erythema that can spread outward, forming a halo of lighter skin around the central spot.
- Development of vesicles or blisters in severe cases, occasionally filled with clear fluid.
- Appearance of a secondary rash (urticaria) that can appear on distant body parts, indicating a systemic response.
The reaction timeline varies. Immediate hypersensitivity presents within minutes to a few hours, with itching and swelling peaking quickly. Delayed papular urticaria emerges 24–48 hours later, persisting for several days before fading. Lesions often resolve without scarring, but persistent scratching may lead to excoriation, infection, or hyperpigmentation.
Systemic symptoms are rare but possible. They may include:
- Generalized hives.
- Facial swelling.
- Difficulty breathing or wheezing, suggesting anaphylaxis; immediate medical attention is required.
Differential diagnosis should consider other arthropod bites, contact dermatitis, and scabies. Distinguishing features of flea‑induced allergy are the typical location on the lower limbs, the presence of a central punctum, and the propensity for grouped lesions. Laboratory testing for specific IgE to flea saliva antigens can confirm sensitization when clinical presentation is ambiguous.