Monday, May 25, 2009


This man presented with the pruritic rash shown above. Actually, even though that's an arm, this infection is most commonly on the lower legs and feet. The only unusual exposure is that he went swimming yesterday when he felt tingling and itching of that arm. About 12 hours later, he got this intensely pruritic rash.

A CBC shows peripheral eosinophilia.

Challenge: Oh yes, in case you were wondering, he swam in a fresh water pond with snails. Does that help your diagnosis?

Image is in the public domain.


tree said...

Ew worms :P


Alex said...

swimmer's itch

Stephanie said...


Anonymous said...

lurker for the last couple months & commenting for the first time...

thanks for this blog, it's been a fun alternative to robbins during ms2 (and boards studying...)

Craig Chen said...

Yes! Well done guys! I'm thrilled...I actually didn't remember what schistosomiasis was until I reread it. Sorry for the late answer...was on call.

This is one form of schistosomiasis (also called bilharziasis), due to infection with parasitic blood flukes. Swimmer's itch, described here, is most often caused by Schistosoma japonicum (rarely S. haematobium). The local dermatitis is due to penetration of skin by cercariae. The life cycle is complicated but female trematodes produces eggs which, upon contact with water, release miracidium larva that infect the intermediate host snail. These multiply into sporocysts and then cercarial larvae that seek the definitive host, humans.

Sources: UpToDate; Wikipedia.

Dr. Yahya said...