Green Nail Syndrome

Green discoloration of the fingernailsdeveloped 6 weeks after a 29-year-oldwoman had artificial nails placed duringa manicure. The patient was a doctorof pharmacy degree candidate whowas married and had 2 children.

She denied systemic symptoms.Her medical and surgical historieswere unremarkable. She took no prescriptionmedications and did notsmoke cigarettes or drink alcohol.

The patient was afebrile. Greendiscoloration of the nail plate wasnoted on the fingers of the right hand;the nail folds were normal. Fungal culturesof nail scrapings were negativefor growth in Sabouraud dextrose agarand Mycosel agar; Pseudomonasaeruginosa infection was diagnosed.

Fifteen-minute alcohol soaks 2or 3 times a day and frequent nail clippingwere prescribed. The conditionresolved completely in 3 weeks.

THE GREEN NAILSYNDROME
Pseudomonas species and, lesscommonly, Candida species are theprimary causes of "green nail syndrome."The differential diagnosisalso includes^1,2:

• The use of green dyes, chemicals,lacquers, or paints.
• Aspergillus infections.
• Subungual hematomas.
• Malignant melanoma.

Paeruginosa (formerly Bacilluspyocyaneus) is a motile, aerobic,gram-negative organism that growsoptimally at 37^oC (98.6^oF).¹ "Aeruginosa,"derived from the Latin wordfor copper rust, refers to the distinctiveblue-green pigment produced bythe organism. This pigment adheresto the undersurface of the nail plate,causing the green color; portions ofor the entire nail plate may be involved.Green-striped nails arise fromthe deposition of pigment during repeatedparonychial infections.³

PATHOGENESIS
Paeruginosa is an opportunisticpathogen that causes disease primarilyin persons with impaired immunologic mechanisms.² The stratumcorneum is the first line of defenseagainst Pseudomonas skin infections;in a normal host, the organism is unableto withstand the dryness ofthe skin. Frequent hydration of theskin increases susceptibility to the infection.Thus, green nail syndromefrom Paeruginosa commonly is seenin bakers, dishwashers, barbers,medical personnel, and others whosehands are frequently submerged inwater.

Nail trauma of any kind-includingonychophagia, onychotillomania,hangnails, manicures, heat, occlusion,sweating, dermatitis, ulcerations, orexcoriations-predisposes one toparonychia. Secondary Pseudomonasinfections occur in diseased nails.⁴Broad-spectrum antimicrobials mayfacilitate colonization. Pseudomonasinfections are more common in neutropenicand immunosuppressedpatients.²

Persons with artificial nails alsoappear to be predisposed to Paeruginosanail infections (Box). This susceptibilitymay be related in part tonail trauma sustained during the applicationof the false nails and/or to theincreased hydration permitted by thehighly permeable acrylic monomersthat form sculptured fingernails.⁵

DIAGNOSIS
Perform a Gram stain and cultureto confirm suspected Pseudomonasnail infections. A pigment solubilitytest also may be elucidating. Toperform this test, immerse a sampleof the affected nail in 1 mL of chloroformor distilled water. If Paeruginosais present, the organism'swater-soluble pigment will turn theliquid bluish green in 24 hours. Candidaand Aspergillus pigment solubilitytests are negative because nosoluble pigment is produced bythese organisms.²

Standard practice is to obtainscrapings of green nails for culture onSabouraud dextrose agar and Mycoselagar. If these fungal cultures are negative,empirically treat the patient forPseudomonas infection.

TREATMENT
Topical treatments include bacitracin;polymyxin B; acetic acid in 50%alcohol; 15% sulfacetamide in 70%ethyl alcohol; or 2 or 3 daily soaks inalcohol or household bleach, diluted1:4.² Alternatively, a 4-week course oforal ciprofloxacin, 500 to 750 mg bid,is effective.⁶ Treatment of Pseudomonas-infected nails is more successfulwhen predisposing factors, such ashydration and trauma, are avoided.