flea bites
Last reviewed 01/2018
The flea bite may only be noticed several days later as it is the delayed hypersensitivity to a specific toxin which causes the reaction. It may cause haemorrhagic spots, and/or papular urticaria. The lesions are asymmetric, often grouped.
Haemorrhagic spots are surrounded by wheals, and often occur as recurrent crops. They are more linear than in chicken pox and subside in 24 hrs to produce itch papules.
Papular urticaria are itchy papules occurring some 6 weeks after the bites.
Cat flea bites are numerous on the lower leg with few bites on the trunk, often on back of thighs and buttocks in young adults.
Human fleas tend to nest in the seams of clothes and are therefore more noticable on the trunk.
Bird fleas are more common on exposed skin of arms.
Another common source are hedgehogs and rabbits.
Scratching may produce thickened lichenified pigmented papules.
About 95% of the population of fleas related to a pet will be in the form of eggs, larvae and pupae (i.e. in the household) rather than on the animal (2).
Reference:
- Prescribers' Journal (1998), 38(2), 80-6.
- Kramer F, Mencke N. Flea biology and control. The biology of the cat flea. Control and prevention with imidacloprid in small animals. Berlin: Springer-Verlag, 2001.