Nail disorders: when to refuse the service

The exam does not ask you to diagnose. It asks you to sort what you see into two piles: conditions you may work over, and conditions that end the appointment with a referral. The sorting rule is whether there is any sign of infection or inflammation.

May be serviced	Onychophagy — bitten nails
Onycholysis	The plate has separated from the bed at the free edge, with no infection
Leukonychia	White spots, usually minor trauma to the matrix
Horizontal ridges	A past interruption to nail growth at the matrix
Refer	A thickened, discolored, crumbling nail
Refer	Any sign of infection or inflammation in the nail or the skin around it
Never	Cutting out the corner of an ingrown toenail
Before any manicure	Examine the nails and the surrounding skin
A client with diabetes	Reduced sensation and slower healing make a small injury serious

Where the point is lost: How you decline is itself an exam answer. A visible contagious condition is handled privately and courteously, with a referral to a physician — not announced across the salon, and not explained by naming what you think it is, which would be diagnosing. And before any product touches a client for the first time, confirm known allergies and sensitivities.