Nail Diseases by Name for the Nail Tech Exam

Nail Anatomy in One Paragraph

Before naming the condition, name the part. The free edge is the section of nail plate that extends past the fingertip. The nail plate is the hard keratin shield. The lateral sidewalls are the folds of skin along each side of the plate. Underneath sits the nail bed, which supplies blood and nutrients. The lunula is the visible portion of the matrix at the base of the plate. The cuticle is dead tissue that sheds from the underside of the eponychium, while the eponychium itself is the living skin at the proximal nail fold. You push back and remove cuticle, you do not cut the eponychium. The hyponychium is the seal under the free edge that keeps debris and pathogens out of the nail bed.

Diseases You Cannot Service

If you see signs of active infection, you stop service in that area and refer the client to a physician. Servicing an infection spreads it to your tools, your station, and the next client. The conditions below all warrant referral.

Onychomycosis (Tinea Unguium)

Fungal infection of the nail. The plate becomes yellow, thickened, and brittle, and you may see white powder or crumbly debris under the plate. It shows up most often on toenails because shoes trap warmth and moisture. Onychomycosis is contagious and progressive. Refer to a physician or podiatrist.

Paronychia

Bacterial or fungal infection of the tissue around the nail. The skin looks red, swollen, and painful, and pus may be present. Paronychia often follows aggressive cuticle work or a torn hangnail. Active paronychia is a hard refusal.

Pseudomonas (Greenies)

Green or black-green stain under the natural nail or under an enhancement, caused by Pseudomonas aeruginosa bacteria. Lifting product traps moisture and bacteria, and the bacteria leave behind a colored byproduct. The green color itself is a stain on the keratin, but it tells you contamination took place. Remove the enhancement, do not cover the discoloration with new product, and refer if the surrounding skin is red, painful, or weeping.

Onychia

Inflammation of the nail matrix, often with redness and pus near the lunula. It points to an infection deep enough to threaten future nail growth. Refer to a physician.

Pyogenic Granuloma

A red, raised lesion of vascular tissue near the nail that bleeds easily on contact. It can grow under or beside the plate after trauma or chronic irritation. This is medical treatment territory, not a salon problem.

Tinea Pedis (Athletes Foot)

Fungal infection of the skin of the feet. The skin between the toes itches, peels, and may crack. Tinea pedis can spread to toenails as onychomycosis. Refuse pedicure service on infected feet and refer.

Plantar Warts

Caused by human papillomavirus. Rough, callused growths on the sole of the foot, often with tiny black dots inside. They are contagious through shared moisture and surfaces. Skip service in the affected area.

Severe Nail Psoriasis

An autoimmune skin condition that affects the nail. Look for pitting in the plate, onycholysis (separation), and the oil drop sign, a yellow-brown patch under the plate. Mild, stable psoriasis may be serviceable with care. Active flares with cracking, bleeding, or open skin require medical management first.

Disorders You Can Service With Care

Disorders are conditions of the nail unit that are not infectious. You can perform a service, but you adjust technique, document the condition, and avoid making it worse.

Onycholysis

Separation of the nail plate from the nail bed, usually starting at the free edge. Common causes are trauma, aggressive filing under the free edge, harsh solvents, and prolonged moisture. Service with care. Do not push instruments under the separated plate, do not apply enhancement over the lifted area, and trim short to prevent further peeling.

Onychophagy (Bitten Nails)

Habitual nail biting. The free edge is short, irregular, and the surrounding skin may be torn. You can service these clients carefully. Tips, wraps, or a basic manicure can encourage growth and break the habit. Avoid working into the matrix area if the skin is broken.

Hangnail (Agnail)

A piece of torn cuticle or skin along the lateral sidewall. Trim it cleanly with sanitized nippers. Never pull or tear it, and do not cut into living skin or the eponychium.

Beaus Lines

Horizontal ridges or grooves running across the nail plate. Caused by a temporary disruption of matrix activity, such as a high fever, severe illness, chemotherapy, or direct trauma to the matrix. They grow out as the plate grows. You can buff lightly to smooth the appearance if the client wants.

Leukonychia

White spots or streaks on the plate caused by minor trauma to the matrix, often from bumping the cuticle area. They are cosmetic only and grow out. Polish covers them.

Koilonychia (Spoon Nails)

Concave, scooped-out nails that can hold a drop of water. Often associated with iron deficiency anemia or other systemic conditions. Service is fine, but mention the appearance to the client and recommend they see a physician for a blood workup.

Onychorrhexis

Longitudinal ridges and brittle, splitting nails. Causes include dehydration, aging, repeated wet-dry cycles, and harsh chemicals. File gently in one direction, hydrate with cuticle oil, and recommend a daily oil habit at home.

Onychogryphosis (Rams Horn Nail)

Severely thickened, curved nail that grows in a horn-like shape. Common in elderly clients and on neglected toenails. Standard nippers and files cannot safely manage it. Refer to a podiatrist.

Pterygium

Forward growth of the eponychium or the hyponychium that adheres to the nail plate. True pterygium is living skin, so do not cut it. Soften with a cuticle remover, push back gently, and treat the surrounding tissue with oil. Cutting living skin causes pain, bleeding, and infection risk.

Onychocryptosis (Ingrown Nail)

The corner of the nail plate grows into the surrounding skin. The area may be tender, red, or swollen. If the area shows pus, heavy redness, or warmth, refuse service and refer. If it is mild and not infected, file the corner clean and instruct the client to cut straight across going forward.

Quick Reference Table

Service Decision Rules

When the textbook name escapes you on exam day, fall back on these three rules:

• Active infection signs (redness, swelling, pus, weeping, warmth, fungal discoloration): refuse service and refer to a physician.
• Healed condition or cosmetic concern (ridges, white spots, mild lifting, thin nails): service with adjusted technique and document what you saw.
• When in doubt: refuse service and recommend the client see a physician. The exam, the licensing board, and your insurance all back this answer.

Exam point: The prefix onycho- means nail. Once you see -mycosis (fungus), -lysis (separation), -rrhexis (rupture), -phagy (eating), -cryptosis (hidden/ingrown), or -gryphosis (curved), you can decode an unfamiliar term on the test even if you have not memorized it.

Common mistake: Treating pseudomonas as a fungal stain that you can cover. It is bacterial contamination. Cover it with new product and you trap the bacteria, deepen the color, and risk a real bed infection. Always remove the enhancement and let the nail breathe.