Seal Finger/Whale Finger.

Presents with an exquisitely tender, swollen, right index finger, with a violaceous blister on its dorsum.

(Image courtesy- Google)

Cause:  erysipelothrix rhusiopathiae, seal finger (also known as “spekk” or “blubber” finger)
Gram positive Bacillus.
Catalase negative.
H2S positive.

Traditionally an occupational hazard of seal hunters, it is increasingly common in wildlife workers.

Symptoms may appear 1 day to 3 weeks after exposure.

Treatment: Penicillin G.