Which of the following diseases is most likely to be acquired from a hot tub or whirlpool?

• A. Q fever
• B. Erysipelas
• C. Acinetobacter cellulitis
• D. Pseudomonas dermatitis

Answer: (D)

The situation tests understanding of infections tied to warm, moist environments like hot tubs. Pseudomonas aeruginosa thrives in inadequately disinfected, warm water, so exposure to a hot tub or whirlpool can lead to hot tub dermatitis, also called hot tub folliculitis. It presents as a pruritic papulopustular rash that appears about 24–48 hours after soaking. The illness is usually self-limited and resolves with supportive care; avoiding hot tubs until it clears and ensuring proper disinfection reduces risk.

Why the other options don’t fit here: Q fever comes from Coxiella burnetii—an aerosol exposure linked to livestock, not water exposure. Erysipelas is a superficial skin infection caused by Streptococcus pyogenes, presenting as a sharply demarcated, fiery red area often on the face or legs, not related to hot-tub exposure. Acinetobacter cellulitis tends to occur in hospital or wound settings and isn’t classically associated with hot tubs.