ONYCHOLOGY

Question 1

how is the normal nail plate?

Answer 1

usually clear and transparent allowing visualization of the underlying pink nail bed

Question 2

normal nail matrix or root starts in utero at about how many weeks?

Answer 2

9-10 weeks

Question 3

the entire nail unit is derived from?

Answer 3

ectoderm

epidermis

Question 4

what is this disease?

aka koenen tumor (benign)
inherited neurocutaneous
multiple benign hamartomas
variable expression
a clinical diagnosis

Answer 4

periungual fibromas of tuberous sclerosis complex

Question 5

– Abnormal thickening
but not distorted in
shape
– Greater than 0.2 mm in
thickness

Answer 5

Onychauxsis

Question 6

– Greater thickening in
both transverse and
longitudinal dimensions

Answer 6

Onychogryphosis

Question 7

– Normal but elongated

Answer 7

Hypertrophic nails

Question 8

– traumatic or surgical and partial or complete

Answer 8

Matrix destruction

Question 9

– intermittent atrophy produces Beau’s lines
– continued produces onychomadeisis – shedding
• Found in Hand Foot and Mouth disease

Answer 9

Atrophy of matrix

Question 10

– gradual microtraumatic‐onychochauxsis
• uniform flat thickening 1‐3 mm thick

– acute traumatic onychogryphosis
• distorted in all planes 3‐15 mm thick

Answer 10

Hypertrophy of matrix

Question 11

– due to allergic contact dermatitis to acrylic

Answer 11

Onycholysis

Question 12

what are the primary tumors?

metastatic tumors?

Answer 12

squamous cell carcinoma
basal cell carcinoma
kaposi sarcoma
melanoma

breast cancer produces phalangeal osteolytic focus

Question 13

what is this malignant tumor?

Commonest malignant tumor of the nail unit

Answer 13

Squamous cell carcinoma SCC

Question 14

what is this malignant tumor?

• Although BCC are the most common malignant skin tumor, they are very rare as a
subungual tumor

• Pedal nail units usually protected from solar
exposure

Answer 14

Basal cell carcinoma BCC

Question 15

what is this carcinoma?

Resembles benign diseases

Look for nail plate variation and nodularity

Melanonychia, erythronychia,
irregular vascularity, splinter
hemorrhages

Answer 15

Subungual SCC

Question 16

subungual metastases largely occur from?

Answer 16

lung

Question 17

first sign of previously unsuspected primary malignancy in 44% of the patients with sublingual metastases?

Answer 17

– Painful erythematous swelling of the distal digit
– Red to violaceous nodule distorting nail soft tissue
– Often mistaken as an acute infection.

Question 18

metastatic sarcoma presents
with white lines on all of her
fingernails

– Not toenails

Answer 18

Muehrcke’ Lines

Question 19

Typically non‐painful spreading
discoloration of nail bed

2/3 presents as longitudinal
melanonychia

Diagnostic delay ‐ poor prognosis

Equal sex predilection

Answer 19

Subungual Melanoma

Question 20

characteristics of Subungual Melanoma?

Answer 20

age of patient
band of brown
breadth greater than 3 mm
border irregular or blurred
change in the band
digit involved
decreasing frequency 
extension of pigment
fx of melanoma

Question 21

Dermoscopy Signs of

Subungual Melanoma?

Answer 21

brown background
irregular
micro hutchinson sign
biopsy is gold standard

Question 22

1/3 of subungual melanomas are amelanotic

Poor prognosis

Older patients

Linear irregular vessels
Milky red areas

what is this?

Answer 22

Amelanotic Melanoma

Question 23

Subungaul hematoma should growth out how many mm per month?

Answer 23

1mm per month

Question 24

Clinical observation of
subungual pigment
appears to stain the
overlying cuticle because
of nail plate transparency
but actually does not.

Absence does not necessarily
imply benignity

what is this sign?

Answer 24

Pseudo‐Hutchinson’s Sign

Question 25

‘The Greenies’ ‐ nail technician’s name for chronic
subungual Pseudomonas infection

Prolonged immersion in fresh water

Green is pyocyanin pigmented subungual debris

Topical fluoroquinolones

Antiseptic soaks for 2 weeks

Oral ciprofloxacin for four weeks has been found to be effective

Treatment failure ‐ cultures and sensitivity testing, nail removal

Answer 25

Green Nail Syndrome