House centipede bites and stings can cause dermatitis and secondary infections.


Causes

House centipedes are grayish white. The adults are 0.5 - 2cm long and 0.3 - 0.5cm wide. Their bodies are segmented, with about 15 segments, each segment is with a pair of slender legs, and the last pair of legs are longer. There are linear black spots from head to tail on the back. The abdomen is grayish white, and there are one pair of tentacles on head and tail, respectively. There is a pair of black eye spots on both sides and a large venomous jaw on the head. There is a venomous claw on the end, communicated with the venom glands in the body.

Figure 1 house centipede


Signs and Symptoms

Once house centipedes on the human skin are frightened or slapped, the venomous jaw on the head can bite the skin, and the venomous claw on the end can stab the skin and release venom, causing funicular erythema and vesicles within few hours. There are initially translucent vesicles, evolving into turbid pustules or bloody vesicles, with obvious red halos. There are often erosions due to scratches. If there is secondary infection, the skin lesions resemble gangrenous herpes zoster, with pruritus and pain. The venom is weakly acidic or neutral by pH 6.3 - 7, and the causative factor is not the stimulation of strong acid but the toxin. If there is no secondary infection, skin lesions subside spontaneously in 3 - 5 days, leaving pigmentation.


Diagnosis

If there are a history of exposures to house centipedes and clinical presentations, the condition can be diagnosed.


Treatment

The bite sites can be cleaned with 3% boric acid solution, and topical anti-inflammatory ointments or lotions, such as calamine lotion containing 1% phenol or 1% mint, can be applied. If there is secondary infection, anti-inflammatory treatment can be given, and antihistamines can be administered in patients with obvious symptoms.