Study guide
8.2 Nail Disorders, Diseases & Safety Contraindications
Arizona Cosmetology Licensing Exam Study Guide Exam
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1 Chapter 1: Arizona Cosmetology Licensing & Board Regulations
1.1 The Arizona Barbering and Cosmetology Board & Licensing Routes 1.2 The Two Arizona Examinations, Scoring & Fees 1.3 License Renewal, Display, Inactive Status & Reactivation 1.4 Establishments, Inspections, Scope of Practice & Discipline
2 Chapter 2: Infection Control, Safety & First Aid Standards
2.1 Principles of Microbiology & Pathogens 2.2 Decontamination Levels: Cleaning, Disinfection & Sterilization 2.3 OSHA Safety Standards & SDS Compliance 2.4 Blood Exposure Protocols & First Aid Emergencies 2.5 Arizona Infection Control Standards in Daily Practice
3 Chapter 3: Human Anatomy, Physiology & Chemistry
3.1 Integumentary System & Skin Anatomy 3.2 Trichology: Hair Structure, Growth & Disorders 3.3 Nail Anatomy, Physiology & Pathology 3.4 Basics of Chemistry & pH Scale 3.5 Muscles of the Head, Face & Neck 3.6 Bones, Muscles & Joints of the Arms, Hands, Legs & Feet 3.7 The Nervous System in Cosmetology 3.8 The Circulatory & Lymphatic Systems
4 Chapter 4: Haircare, Haircutting & Styling Principles
4.1 Hair & Scalp Analysis 4.2 Principles of Haircutting & Elevation 4.3 Wet & Thermal Hair Styling 4.4 Wigs, Hair Additions & Natural Hair Styling 4.5 Hair Care Tools, Electrical Equipment & Safe Handling 4.6 Draping, Shampooing, Conditioning & Scalp Treatments 4.7 Haircutting Implements in Practice & Cutting Techniques 4.8 Hair Design Principles: Face Shapes, Balance & Proportion 4.9 Textured Hair: Curl Patterns, Care & Service Adaptations
5 Chapter 5: Chemical Texture Services
5.1 Chemistry of Perming & Disulfide Bonds 5.2 Permanent Waving Techniques & Wrap Patterns 5.3 Chemical Hair Relaxers & Hydroxide Chemistry 5.4 Keratin Smoothing & Chemical Reforming Procedures
6 Chapter 6: Haircolor & Hair Lightening Services
6.1 Color Theory & Natural Hair Pigment 6.2 Haircolor Classifications & Developers 6.3 Hair Lightening & Decolorizing Services 6.4 Consultation, Predisposition Testing & Color Corrections
7 Chapter 7: Skin Care, Facials & Hair Removal Services
7.1 Skin Analysis, Typing & Conditions 7.2 Facial Treatment Procedures & Cleansing 7.3 Hair Removal Services & Epilation Methods 7.4 Electrotherapy, Facial Machines & Cosmetic Makeup 7.5 Lash & Brow Services and Arizona Eyelash Rules
8 Chapter 8: Nail Care, Manicuring & Nail Enhancements
8.1 Basic Manicure & Pedicure Procedures 8.2 Nail Disorders, Diseases & Safety Contraindications 8.3 Monomer Liquid & Polymer Powder Nail Enhancements 8.4 Light-Cured Gels, Wraps & Electric Filing Safety 8.5 Nail Tools, Equipment & Arizona Foot Spa Disinfection
9 Chapter 9: Salon Business Management, Ethics & Career Practices
9.1 Salon Ownership, Business Structures & Regulations 9.2 Financial Management, Pricing & Retail Sales 9.3 Employment Classification & Tax Compliance 9.4 Professional Ethics, Communication & Client Retention
8.2 Nail Disorders, Diseases & Safety Contraindications
Key Takeaways Explain This Topic AI
Nail diseases such as Onychomycosis, Paronychia, Onychia, and active bacterial infections are strict contraindications requiring immediate refusal of service and medical referral.
Pseudomonas aeruginosa is a bacterial infection (frequently misidentified as mold) that thrives in moist, anaerobic pockets beneath lifted nail enhancements, turning the plate green to black.
Serviceable cosmetic nail disorders include Beau's lines, Leukonychia, Onychophagy, Onychorrhexis, Eggshell nails, and Pterygium when no infection or inflammation is present.
Onychorrhexis is characterized by vertical lengthwise ridges and brittle splits, whereas Beau's lines manifest as transverse horizontal furrows caused by temporary matrix growth interruption.
Pterygium involves an abnormal forward growth of skin adhering to the nail plate that must never be forcibly cut or pulled away.
Last updated: August 2026
A vital responsibility of every licensed beauty professional is distinguishing between serviceable nail disorders (which may be safely cosmeticized in the salon) and non-serviceable nail diseases (which represent strict contraindications to service and require immediate physician referral). Performing nail services on infected or inflamed tissues violates state health laws, risks spreading infectious pathogens across clients, and can cause permanent structural damage to the client's nail unit.
Non-Serviceable Nail Diseases (Strict Contraindications)
Any client presenting with signs of inflammation (redness, swelling, heat, throbbing pain, or pus collection) or active pathogen invasion must be tactfully informed that salon services cannot be performed. The technician must advise the client to consult a licensed physician or dermatologist for medical diagnosis and treatment. [Client Assessment Protocol]
Visual & Tactile Inspection --> Signs of Infection/Inflammation Present?
- |
- +--> YES: REFUSE SERVICE immediately & Refer to Physician
- |
- +--> NO: Proceed with Cosmetic Service using proper modifications
- 1. Onychomycosis (Tinea Unguium)
Onychomycosis (commonly referred to as ringworm of the nail or tinea unguium) is a fungal infection of the natural nail plate. It is caused by dermatophyte fungi that feed on keratin.
Clinical Presentation: Whitish, yellowish, or brownish streak discoloration within the nail plate; severe thickening and distortion of the plate; crumbling free edges; and detachment of the nail plate from the nail bed ( onycholysis ).
Salon Protocol: STRICT CONTRAINDICATION. Fungal spores are highly contagious and easily transmitted via nail files, foot basins, or clippers. All services must be refused.
2. Paronychia
Paronychia is an acute or chronic bacterial infection of the soft tissue folds surrounding the natural nail plate (the eponychium and lateral nail folds).
Clinical Presentation: Intense redness, localized swelling, warmth, severe throbbing tenderness, and frequent pus formation around the nail borders. Commonly caused by Staphylococcus aureus entering through torn cuticles, aggressive nipping of the eponychium, or unsterilized metal pushers.
Salon Protocol: STRICT CONTRAINDICATION. No manicure, pedicure, or enhancement service may be performed on or near the affected digit.
3. Onychia
Onychia is a severe inflammatory disease of the nail matrix beneath the eponychium.
Clinical Presentation: Tissue inflammation, redness, intense pain, and purulent discharge (pus) originating directly from the matrix area, leading to complete loosening and shedding of the natural nail plate.
Salon Protocol: STRICT CONTRAINDICATION. Requires immediate medical intervention. Cosmetic application over an inflamed matrix can cause permanent loss of nail production.
4. Pseudomonas Aeruginosa ("Green Nail" Bacterial Infection)
Often misdiagnosed by untrained technicians as "nail mold" or "fungus," the green or black discoloration observed beneath lifted artificial enhancements is actually caused by a bacterial infection from Pseudomonas aeruginosa . [Development of Pseudomonas Aeruginosa]
Lifted Enhancement + Trapped Moisture/Debris --> Anaerobic Warm Environment --> Bacterial Colony Growth --> Green/Black Pigment Staining
Pathology: Pseudomonas aeruginosa is a common environmental bacterium that thrives in warm, moist, dark, anaerobic (oxygen-depleted) environments. When a gel or acrylic enhancement lifts slightly from the natural nail, moisture and bacterial cells become trapped in the micro-pocket.
Clinical Presentation: Color changes on the nail plate progressing sequentially from light yellowish-green to dark emerald green, and eventually brownish-black as bacterial metabolic byproducts accumulate.
Salon Protocol: If an enhancement is removed and a green stain is discovered on an un-inflamed plate, the enhancement must NOT be reapplied over the discolored area. The nail plate must be cleaned, disinfected, and allowed to grow out completely. However, if the underlying nail bed is tender, swollen, or weeping, it represents an active bacterial disease and must be referred to a doctor.
Nail Disease / Pathogen Primary Cause / Etiology Key Visual Symptoms Salon Action Required
Onychomycosis Dermatophyte fungal infection Yellow/brown crumbling plate, thickening, onycholysis Refuse service; refer to physician
Paronychia Bacterial infection ( Staph ) of nail folds Redness, swelling, heat, pus at cuticle/walls Refuse service; refer to physician
Onychia Bacterial/viral inflammation of matrix Pus from matrix, matrix breakdown, nail shedding Refuse service; refer to physician
Pseudomonas Pseudomonas aeruginosa bacteria in moisture Yellow-green to dark green/black stain under enhancement Remove enhancement; clean; refer if inflamed
Serviceable Cosmetic Nail Disorders
Unlike infectious diseases, nail disorders are non-infectious structural anomalies, systemic cosmetic conditions, or mechanical injuries to the nail unit. Technicians may perform manicuring and enhancement services on client nails exhibiting disorders, provided the surrounding skin is healthy, intact, and free of inflammation.
1. Beau's Lines
Beau's lines are visible transverse (horizontal) depressions or furrows running across the width of the natural nail plate.
Etiology: Caused by a major systemic illness, high fever, severe physical trauma, surgical shock, or adverse drug reaction that temporarily stops or severely impairs matrix cell division for a defined period.
Service Modifications: Serviceable. Gently buff the nail plate with a fine-grit buffer; apply ridge-filling base coats or light-cured gels to smooth the surface contours.
2. Leukonychia
Leukonychia manifests as white spots, flecks, or transverse white bands appearing within the body of the nail plate.
Etiology: Results from minor mechanical micro-trauma to the nail matrix (such as hard tapping or aggressive cuticle pushing). As matrix cells cornify into keratin, air pockets become trapped between cell layers.
Service Modifications: Fully serviceable. White spots cannot be buffed out because they are located within the internal layers of the nail plate; they grow out harmlessly with the free edge.
3. Onychophagy (Bitten Nails)
Onychophagy is the medical term for severely bitten nails resulting from a habit of chewing the nail plate or surrounding eponychium.
Etiology: Habitual nervous chewing leads to extremely short, worn free edges, exposed swollen hyponychium, and wet, traumatized nail beds.
Service Modifications: Serviceable, provided no open bleeding wounds or active infections exist. Frequent basic manicuring or carefully sculpted short monomer/polymer enhancements can help protect the nail bed and break the chewing habit.
4. Onychorrhexis
Onychorrhexis refers to split, brittle, or thin natural nails characterized by series of prominent lengthwise (vertical) ridges running from the cuticle to the free edge.
Etiology: Caused by matrix injury, exposure to harsh alkaline chemicals or solvents, excessive handwashing, age-related dryness, or heredity.
Service Modifications: Serviceable. Avoid aggressive filing of vertical ridges, which thins the natural plate further. Use rehydrating oil treatments, fine-grit smoothing buffers, and protective fabric wraps or gel overlays.
5. Eggshell Nails
Eggshell nails are noticeably thin, white, translucent, exceptionally flexible nail plates that curve downwards over the free edge.
Etiology: Improper nutritional diet, hereditary weakness, nervous disorders, or underlying systemic illness.
Service Modifications: Serviceable, but extremely fragile. File very gently with an ultra-fine abrasive (240-grit or higher); apply protective overlays (such as gel or fabric wraps) to reinforce structural strength.
6. Pterygium (Nail Pterygium)
Pterygium occurs when an abnormal forward growth of living skin adheres firmly to the upper surface of the natural nail plate. [Pterygium Development]
Matrix Injury / Severe Burn --> Abnormal Scar Tissue Formation --> Living Skin Stretches Forward along Growing Nail Plate
Etiology: Typically caused by severe burns, deep mechanical trauma to the matrix, or skin diseases like lichen planus that fuse the eponychium or hyponychium to the growing nail plate.
Service Modifications: Serviceable with extreme caution. NEVER attempt to cut, scrape, or forcibly peel pterygium off the nail plate. Doing so causes severe tissue tearing and infection. Gently massage the area with penetrating oils and apply polish or enhancements only over healthy uncovered plate surfaces.
Serviceable Disorder Physical Appearance Primary Cause Recommended Cosmetic Care
Beau's Lines Horizontal depressions across width Systemic illness, severe fever, surgery Gently buff; apply ridge-filling base coat
Leukonychia White spots / flecks inside plate Matrix micro-trauma trapping air Normal manicure; spots grow out naturally
Onychophagy Severely bitten, short nails Habitual biting of plate/cuticle Soft manicures or short protective acrylics
Onychorrhexis Vertical ridges, split brittle plate Chemical exposure, aging, matrix trauma Hydrating oil treatments, fine buffer, wraps
Eggshell Nails Thin, flexible, curving white plate Diet deficiency, hereditary weakness Fine file only; reinforce with gel/wrap overlay
Pterygium Skin stretched forward on plate Severe burn, matrix scar tissue DO NOT CUT; apply hydrating oils gently