Nail technicians see their clients' nails up close and often, so they may notice changes first. The exam tests what to notice and what to do about it.
What nails are
Nails are layers of a hardened protein called keratin, the same protein found in hair and skin. The cuticle acts as a barrier that helps prevent infection, so a damaged cuticle is an infection risk.
Changes that can signal illness
MedlinePlus says specific kinds of discoloration and changes in growth rate can be signs of lung, heart, kidney and liver disease, diabetes and anemia. A nail technician does not interpret them, but a noticeable change is worth mentioning to the client.
Fungal infection
The CDC lists the signs of a fungal nail infection (onychomycosis): nails that are discolored, thick, fragile or cracked, or separated from the nail bed. It is much more common on toenails and often starts through a small cut near the nail. The EPA advises giving services only on healthy nails.
Melanoma
A new or growing dark streak under a nail, or a changing mole, is a melanoma warning sign; acral-lentiginous melanoma can occur in the nail bed. Suggest the client see a doctor.
Product reactions
Redness, swelling and pain in the nail bed can be a reaction to methacrylates in artificial nail products. Redness, itching and bumps where a product touched the skin suggest contact dermatitis, and an allergy can develop even after years of use.
The rule that always applies
A nail technician recognizes and refers; a doctor diagnoses. See nail and skin disorders: when to refer for the full list.