1. Regional dermatology Nail diseases
Chapter 13
Regional dermatology
Nail diseases

2. The nail Provide strength and protection for the terminal phalanx.
Helps with fine touch and handling of small objects.
Matrix
Produce keratin
Runs from the proximal end of the floor of the nail fold to the distal margin of the lunule.
From this area the nail plate grows forward over the nail bed, ending in a free margin at the tip of the digit.
Nail bed
Producing small amounts of keratin which contribute to the nail and responsible for the ‘false nail’ formed when the nail matrix is obliterated by surgery or injury.
Cuticle
Protect the potential space of the nail fold from chemicals and from infection.

3. Effects of trauma Chronic trauma: Lamellar splitting (housewives)
Permanent ridges or splits in the nail plate
Splinter haemorrhages also be a feature of
Psoriasis of the nail
Subacute bacterial endocarditis
Larger subungual haematomas (exlude subungual melanoma)
Chronic trauma:
Onychogryphosis
Haemorrhage under the nails of the big toes
Gross thickening of toenailsnail
Ingrowing nail
Onycholysis
Bitten nail
Lamellar splitting (housewives)

4. Fig. 13. 21 A subungual haematoma of the big toe
Fig A subungual haematoma of the big toe. Although there was no history of trauma we were happy to watch this grow out over 6 months as the appearance was sudden, the colour was right and the nail folds showed no pigment.
Fig Gross splinter haemorrhages caused by trauma.
Fig Onychogryphosis

5. Onycholysis A separation of the nail plate from the nail bed
May be a result of
Minor trauma
Nail psoriasis
Phototoxic reactions
Repeated immersion in water
Use of nail hardeners
Hyperthyroidism (esp, 4th toe)
Usually, no cause for it is found.
The space created may be colonized by yeasts, bacteria such as P.aeruginosa.

6. Onycholysis
Minor trauma
Onycholysis
The yellow color may indicate a secondary Candida infection.
Psoriasis and tinea have a similar ppearance
Onycholysis
Involvement of many nails

8. Spoon nails
Onycholysis—trauma
Habit-tic deformity
Onycholysis—secondary infection
Leukonychia
Distal splitting

10. Ridging
Beau's lines,
Median nail dystrophy
Chronic paronychia
Acute paronychia

11. Subungual hematoma
Splinter hemorrhages
Trauma
Pseudomonas colonized
Plate hypertrophy

12. The nail in systemic disease
Clubbing
Koilonychia (IDA)
Half-and-half nail (Colour changes)
Beau’s lines
Connective tissue disorders (Nail fold telangiectasia)

13. Clubbing A bulbous enlargement of the terminal phalanx
With an increase in the angle between the nail plate and the proximal fold to over 180°
Association with
Chronic lung disease
Cyanotic heart disease
Familial (rare)
Severe clubbing was accompanied by hypertrophic pulmonary osteoarthropathy.

14. Colour changes half-and-half nail
Chronic renal failure
White proximal
Red or brown distal half
Liver cirrhosis  hypoalbuminaemia
Whitening of the nail plates
Drugs can discolour the nails, as:
Antimalarials
Antibiotics
Phenothiazines

15. CT disorders Nail fold telangiectasia or erythema Physical sign in
Dermatomyositis (cuticles become shaggy)
Systemic sclerosis (finger pulp leads to overcurvature of the nail plates)
SLE
Peripheral circulation is impaired (Raynaud’s phenomenon)
Thin nails
Longitudinal ridging
Partial onycholysis
Fig Large tortuous capillary loops of the proximal nail fold signal the presence of a connective tissue disorder.

16. Nail changes in the common dermatoses
Psoriasis
Arthritis  more likely severe nail involvement is.
Nail changes
Pitting of the surface of the nail plate (best-known)
Oil spots: red/brown areas under the nail plate
Onycholysis
No effective topical treatment

17. Psoriasis—pitting
Psoriasis—onycholysis
Psoriasis-plate alteration
Oil spot

18. Eczema
Itchy chronic eczema  polish nail by scratching.
Eczema of the nail folds may lead to coarse irregularity with transverse ridging of the adjacent nail plates.
Lichen planus
10% have nail changes.
Mostly reversible
Thinning of the nail plate
Irregular longitudinal grooves and ridges.
Pterygium (more severe), which the cuticle grows forward over the base of the nail & attached to the nail plate.
The threat of severe and permanent nail changes can sometimes justify treatment with systemic steroids.
Alopecia areata
More severe the hair loss  more likely nail involvement.
Roughness or fine pitting on the surface of the nail plates
Lunulae may appear mottled.

19. Alopecia areata. Shallow pitting occurs in some patients with alopecia areata.
Lichen planus. Inflammation of the matrix results in adhesion of the proximal nailfold to the scarred matrix, a pterygium

20. Acute paronychia
Inflammation of the nail fold by Staphylococcus infection
Enter through break in the skin or cuticle
Rapid onset of painful, bright red swelling
Pus in the nail fold or under the nail
Treatmnet:
systemic treatment (flucloxacillin, cephalexin or erythromycin)
Inscision & drainage

21. Acute pain and swelling of the lateral nailfold
Erythema and purulent material occur at the proximal nailfold
Elevation of the lateral nailfold releases a large amount of purulent material. Pain is relieved immediately

22. Chronic paronychia Presentation: Tender Swollen nail folds
Opportunistic pathogens (yeasts, G+ve cocci & G-ve rods) colonize the space between the nail fold and nail plate, producing a chronic dermatitis.
Predisposing factors:
Poor peripheral circulation
Wet work
Working with flour
Diabetes
Vaginal candidosis
Overvigorous cutting back of the cuticles
Presentation:
Tender
Swollen nail folds
pus discharge
Loss cuticular seal
Ridged and discoloured adjacent nail plate
The condition may last for years.

23. Dermatophyte infection Investigations: Test the urine for sugar
DDx:
Amelanotic melanoma.
Dermatophyte infection
Investigations:
Test the urine for sugar
Check for vaginal and oral candidosis
Culture (pus
Treatment:
Stop manicuring of the cuticle
Keep hands warm & dry
Imidazole cream
Highly potent topical corticosteroid creams
Itraconazole
Paronychia with secondary nail ridging
Erythema and swelling of the nailfolds.
The cuticle is absent.
Horizontal ridging of the nails

24. 4 types of onychomycosis showing different entry points by infecting organisms.

25. White superficial onychomycosis
Proximal subungual onychomycosis
Distal subungual onychomycosis
Candida onychomycosis
All of the fingernails are infected

26. Dermatophyte infections
Tinea unguium.
T. rubrum & T. mentagrophytes are responsible for most nail infections
also Candida can infect the nail plate
Associated with tinea pedis
The early changes often occur at the free edge & spread proximally
Nail & HIV infections often involve the proximal subungual skin without distal.
Presentation:
Yellow, crumbly & thickened nail plate .
DDx:
Psoriasis
Yeast and mould infections
Investigations:
KOH
Culture
Treatment:
Seldom clears spontaneously
Systemic anti-fungal