The phase during which the follicle canal shrinks and detaches from the dermal papilla is the Catagen phase.

• A. Anagen phase
• B. Telogen phase
• C. Exogen phase
• D. Catagen phase

Answer: (D)

Hair grows in cycles that include a growth phase, a transitional regression phase, and a resting phase. The description of the follicle canal shrinking and detaching from the dermal papilla fits the Catagen phase. It’s a brief, transitional stage after active growth during which the lower part of the follicle regresses, the hair stops growing, and the dermal papilla detaches from the hair matrix. This detachment sets up the follicle for the next phase, the resting telogen phase, after which shedding can occur in exogen. The growth phase (anagen) is when the hair is actively lengthening.