What happens after a bedbug bite? - briefly
A bedbug bite usually causes a small, red, itchy welt that may swell and become inflamed within hours to a few days. The reaction is a localized skin irritation; systemic symptoms or disease transmission are rare.
What happens after a bedbug bite? - in detail
A bed‑bug bite initiates a localized skin reaction that progresses through several stages.
Immediately after the puncture, saliva containing anticoagulants and anesthetic compounds is injected. The anesthetic delays the perception of pain, so the bite often goes unnoticed at first.
Within a few minutes to an hour, the immune system detects foreign proteins, triggering the release of histamine and other mediators. This causes:
- Redness around the puncture site
- Swelling that may expand to a few millimetres
- A prickling or itching sensation
The reaction peaks between 24 and 48 hours. In most individuals, the lesion resolves spontaneously within a week, leaving a flat, discoloured spot that may persist for several weeks.
Some people develop a more pronounced response known as a hypersensitivity reaction. Signs include:
- Larger, raised welts (often called “hives”)
- Intense itching that leads to scratching and secondary infection
- Multiple bites arranged in a linear or clustered pattern
When secondary infection occurs, bacterial colonisation—commonly Staphylococcus aureus or Streptococcus pyogenes—produces additional symptoms: increased warmth, pus formation, and possible fever. Medical evaluation is warranted in such cases.
Systemic effects are rare but documented. They may involve:
- Generalised itching or rash
- Nausea, headache, or fatigue
- In extreme cases, anaphylactic shock, especially in individuals with known severe allergies
Management focuses on symptom relief and prevention of complications. Recommended measures include:
- Washing the area with mild soap and water to reduce bacterial load
- Applying topical corticosteroids or antihistamine creams to diminish inflammation and itching
- Oral antihistamines for widespread itching
- Keeping nails short to minimise skin damage from scratching
If infection signs appear, a healthcare professional may prescribe topical or oral antibiotics. Persistent or worsening lesions should prompt a medical review to exclude other dermatological conditions.
Eliminating the source of infestation—through thorough cleaning, vacuuming, and professional pest control—prevents further bites and reduces the risk of repeated skin reactions.