GOLJY SKIN. Flashcards
1
Q
stratum basalis
A
actively dividing stem cells along BM; mitoses limited to this area
2
Q
stratum spinosum
A
contains desmosome attachments
3
Q
stratum granulosum
A
granular layer with keratohyaline granules
4
Q
stratum corneum
A
anucleate cells with keratin –> site for superficial dermatophyte infections
5
Q
embryonic origin of melanocytes
A
neural crest
6
Q
melanin is synthesized from (1) in (2)
A
(1) tyrosine (2) melanosomes
7
Q
differences in skin color of whites vs. blacks
A
whites - melanin is degraded faster and melanomsomes concentrated to basal layer. blacks = melanosomes present in all layers; melanocytes are larger with more dendritic processes = NUMBER of melanocytes is essentially the same in ALL races
8
Q
macule
A
pigmented or erythematous FLAT lesion on epidermis ex. tinea versicolor
9
Q
papule
A
peaked or dome-shaped surface elevation
10
Q
nodule
A
elevated, dome-shaped lesion > 5 mm in diameter ex. basal cell carcinoma
11
Q
plaque
A
flattened, elevated area on epidermis > 5 mm in diameter ex. psoriasis
12
Q
vesicle
A
fluid-filled blister
13
Q
bulla
A
fluid-filled blister > 5 mm in diameter ex. bullous pemphigoid
14
Q
pustule
A
fluid-filed blister with inflammatory cells ex. impetigo
15
Q
wheal (hive)
A
edematous, transient papule or plaque caused by infiltration of dermis by fluid ex. urticaria
16
Q
scales
A
excessive number of dead keratinocytes produced by abnormal keratinization ex. seborrheic dermatitis
17
Q
hyperkeratosis
A
increased thickness of stratum corneum produces scaly appearance of skin ex. psoriasis
18
Q
parakeratosis
A
persistence of nuclei in stratum corneum layer ex. psoriasis
19
Q
papillomatosis
A
spire-like projections from surface of skin or downward into papillary dermis
20
Q
acantholysis
A
loss of cohesion between keratinocytes ex. pemphigus vulgaris
21
Q
common wart is caused by..
A
human papillomavirus (HPV: DNA virus)
22
Q
treatment of common warts
A
(1) cryotherapy with liquid nitrogen (2) salicylic acid, trichloroacetic acid
(3) imiquimod (induces cytokines)
23
Q
molluscum contagiosum is caused by..
A
poxvirus - DNA virus
24
Q
molluscum contagiosum
A
bowl shaped lesions with central keratin filled depression containing viral particles (molluscum bodies)
25
transmission of molluscum contagiosum
sexually transmitted in adults (esp. AIDs patients): self-inoculation by scratchin
26
treatment of molluscum contagiosum
if immunocompetent = 6-9 months, spontaneous remission; cryotherapy
27
what causes rubeola?
RNA paramyxovirus causes "regular" measles
28
clinical features of rubeola measles
(1) prodrome = fever, cough, coryza, conjunctivitis (2) Koplik spots on buccal mucosa
(3) maculopapular rash after spots disappear
29
pattern of rash in rubeola measles
starts on head then moves to trunk and extremities - confluent on trunk but discrete on extremities
30
complications of rubeola measles
(1) giant cell pneumonia - Warthin-Finkeldey multinucleated giant cells (2) acute appendicitis
(3) otitis media
(4) encephalitis
31
what causes rubella?
german "3 day" measles --> RNA toga virus
32
clinical features of rubella
(1) Forchheimer's spots (2) maculopapular rash lasts 3 days
(3) painful post-auricular lymphadenopathy
(4) polyarthritis -common in adults
(5) congenital anomalies
33
Forchheimer's spots
dusky red spots that develop on posterior soft/hard palate that develop at the beginning of the rash in rubella measles
34
pattern of rash in rubella (german measles)
begins first at hairline and rapidly spread cephalocaudally; macules/papules are discrete (not confluent) and it fades in 3 days
35
which one is teratogenic? rubeola or rubella?
RUBELLA
36
erythema infectiosum (fifth disease) is caused by..
parvovirus B19 - DNA virus
37
clinical features of erythema infectiosum
(1) most often in school-aged children (2) net-like erythema type of rash that begins on cheeks (slapped face) and extends to trunk and proximal extremities
(3) adults - polyarthritis
38
which two viruses cause polyarthritis in adults?
rubella; parvovirus
39
roseola infantum is caused by..
human herpesvirus 6 (DNA virus)
40
MC viral exanthem in children
roseola infantum
41
clinical features of roseola infantum
(1) erythematous macules on soft palata 48 hours before rash (2) maculopapular rash occurs abruptly after 3-7 days of high fever --> common cause of febrile convulsions
42
where does varicella-zoster virus remain latent?
in cranial and thoracic sensory ganglia
43
when is patient infectious with varicella (chickenpox)?
one week before rash starts and one week after rash until vesicles becomes crusted
44
characteristics of varicella (chickenpox) rash
(1) pruritic - progresses from macules to vesicles to pustules (2) all stages are present simultaneously
(3) lesions are most prominent on trunk
45
complications of varicella (chickenpox) in children
(1) associated with Reye syndrome (2) self-limited cerebellitis
46
complications of varicella (chickenpox) in adults
(1) pneumonia (2) encephalitis
| (3) hepatitis
47
clinical feature of herpes zoster (shingles)
prodrome of radicular pain and itching before rash occurs’; painful vesicles/pustules follow sensory dermatomes
48
treatment for herpes zoster (shingles)
prevention with immunization; analgesics for pain; acyclovir/valacyclovir/famiciclovir - immunocompromised pts
49
toxic shock syndrome
TSST from staph aureus --> produces fever, hypotension along with desquamating, sunburn like rash
50
hidradenitis suppurativa
chronic conditions caused by staph aureus with swollen, painful, inflamed apocrine glands (axillae, groin) with the presence of sinus tracts
51
common staph aureus skin infections
abscess; post-surgical wound infections; hidradenitis; impetigo
52
2nd MCC of impetigo
streptococcus pyogenes
53
impetigo
rash usually begins on face with vesicles/pustules that rupture to form honey-colored, crusted lesions
54
scarlet fever
pt is febrile with sore throat --> erythematous, sand-papery rash beginning on face and neck and spreads; after 6 days it desquamates
55
strawberry tongue
in scarlet fever, the tongue is covered by white exudate studded with prominent red papillae; when white disappears, tongue is beefy red
56
treatment of scarlet fever
penicillin V
57
erysipelas
cellulitis with raised borders and surface appears like orange peel; surface is hot and bright red --> usually on face and lower extremities
58
tuberculoid leprosy
(1) granulomas present (2) positive lepromin skin test - intact cellular immunity
(3) localized skin lesions with nerve involvement
- anesthetic macules with hypopigmentation
- digital amputation
59
patient comes in with nodular lesions on his face but with a negative lepromin skin test -- you test further, and learn there is no granulomas but numerous bacteria are present within foamy macrophages --> what does he have? and how do you treat this?
lepromatous type of leprosy w/ classic leonine facies -Tx. Dapsone + Rifampin + Clofazimine
60
acne vulgaris
chronic inflammation of pilosebaceous unit - propionibacterium acnes produces bacterial lipase which makes irritating fatty acids responsible for inflammation
61
non-inflamed comedones
plugging of outlet of hair follicle by keratin debris open = blackhead; closed = whitehead
62
superficial mycoses (dermatophytoses)
fungal infection of stratum corneum or its adnexal structures; usually occur in warm, humid climates and present with scaling rash
63
diagnosis of superficial mycoses
Wood's lamp (UVA fluorescent light) and KOH
64
superficial fungal infection of scalp
tinea capitis
65
MCC of tinea capitis in blacks that also has a negative Wood's lamp reaction
trichophyton tonsurans- infects inner hair shaft
66
MCC of tinea capitis in whites with a positive Wood's lamp reaction
microsporum canis/andouinii - infects outer hair shaft
67
clinical features of tinea capitis
circular or ring shaped patches of hair loss (alopecia) and black dot is present where hair breaks off
68
treatment for tinea capitis
oral terbinafine (oral imadizoles do not work)
69
MCC of all other tineas (other than capitis)
trichophyton rubrum - tx. with topical agents (miconazole, clotrimazole)
70
clinical features of tinea corporis
aka. ringworm - annular lesions with elevated, red, scaly border and tendency for central clearing
71
MC tinea infection
tinea pedis
72
tinea pedis (athletes foot)
usually caused by sweating - macerated scaling rash between the toes - in elderly, diffuse plantar scaling
73
"jock itch"
tinea cruris - also caused by excessive sweating and is marked by a rash that is not annular but has elevated, scaly borders
74
tinea unguium
nail onychomycosis = raised, discolored nail and the nail plate is white, thick and crumbly
75
treatment of onychomycosis
oral terbenafine --> topical agents do not work
76
patient comes in with alterations in skin pigmentation and complains of inability to tan and hyperpigmented, scaly skin in the winter months - diagnosis? treatment?
diagnosis = tinea versicolor. treatment = topical selenium sulfide or oral ketoconazole
77
which organism causes tinea versicolor?
malesezzia furfur - spaghetti and meatballs appearance on KOH smear
78
how does malesezzia furfur cause symptoms of tinea versicolor?
(1) fungus derived acids inhibit tyrosinase in melaoncytes from synthesizing melanin = hypopigmentation (2) fungus induces enlargement of melanosomes in melanocytes along basal cell layer = hyperpigmentation
79
intertrigo
erythematous rash in body folds caused by candida albicans ex. rash under breasts, diaper rash
80
which other organism can cause onychomycosis?
candida albicans
81
what other condition does malesezzia furfur cause?
seborrheic dermatitis aka. dandruff
82
seborrheic dermatitis is commonly associated with..
Parkinson's disease - AIDs and AIDs-related complex
83
cradle cap in newborns
seborrheic dermatitis caused by m.furfur
84
sporotrichosis
subcutaneous mycotic infection caused by sporothrix schenckii characterized by chain of suppurating lymphocutaneous nodules
85
causes of sporotrichosis
traumatic implantation of fungus by rose gardening, sphagnum peat moss, splinters from carpentry work, landscapers, berry pickers
86
treatment of sporotrichosis
(1) oral itraconazole (2) saturated solution of potassium iodide - poorly tolerated
87
cutaneous larva migrans
caused by dog/cat hookworm = Ancylostoma braziliense - larva penetrate the skin (from sand) and produce serpiginous tunnels in skin with intense pruritus, scrathing and eosinophillia
88
treatment of cutaneous larva migrans
ivermectin
89
chiggers
small red mites that cause intense pruritic, red papular/uriticarial/vesicular rash on legs and areas of tight fitting clothing
90
head lice
pediculus humanis capitis - lay eggs (nits) on hair shaft and cause itching of scalp
91
body lice
pediculus humanis corporis - live on the surface of the skin and breed in clothing causing papular, itchy skin lesions
92
bedbug
cimex leticularis --> commonly infest dwellings and feed on human blood (just before dawn, drawn by warmth and CO2) causing intensely pruritic red papules/wheals
93
solar lentigo
brown macules located on sun-exposed areas in elderly - aka "liver spots" due to increased number of melanocytes
94
normal number of melanocytes with increase in melanosomes seen in...
freckles
95
vitiligo
autoimmune destruction of melanocytes causing areas of skin depigmentation --> common in blacks
96
albinism
deficiency of tyrosinase leading to absence of melanin in melanocytes
97
melasma
macular, hyperpigmented lesions on forehead and cheeks commonly associated with pregnancy, OCP use and sunlight in females
98
treatment of melasma
application of hydroquinine to skin
99
MC nevus in children
junctional nevus
100
MC nevus in adults
intradermal nevus
101
dysplastic nevus (atypical mole)
usually > 6 mm, variegated in color with an erythematous background and irregular borders
102
dysplastic nevus syndrome
AD with > 100 nevi on the skin with most patients developing malignant melanoma
103
leading cause of death due to skin cancer
melanoma (increasing in frequency)
104
risk factors for malignant melanoma
(1) excessive sunlight exposure at an early age = most impt (2) history of a family mb with melanome
(3) use of tanning booths
(4) dysplastic nevus syndrome
(5) history of melanome in first/second degree relative
(6) xeroderma pigmentosum
105
radial growth phase of melanoma
initial phase of invasion where it spreads laterally in papillary dermis with no metastatic potential
106
vertical growth phase of melanoma
final phase of invasion where it penetrates the reticular dermis and with metastatic potential
107
ABCD signs of malignant melanoma
Asymmetry; Borders - irregular; Color - changes; Diameter - increased > 6 mm
108
superficial spreading melanoma
MC type of malignant melanoma = develops on lower extremities, arms and upper back
109
lentigo maligna melanoma
common in elderly and occurs on parts of the face exposed to the sun; least likely to have vertical growth and thus, best prognosis
110
nodular melanoma
no radial phase (only vertical) and can be found in sun-exposed areas, esp trunk; poor prognosis
111
acral lentiginous melanoma
melanoma that is NOT UV-related and occurs on the palm, sole and beneat the nail; usually in Asians and Blacks
112
prognosis of malignant melanoma depends on..
depth of invasion
113
MC benign tumor of skin in old people
seborrheic keratoses = benign, pigmented epidermal tumor
114
55 year old patient comes in complaining of macular/verrucoid lesions that have a stuck on appearance located on his face and shoulders - diagnosis?
seborrheic keratoses
115
Leser-Trelat sign
rapid increase in number of keratoses which is a phenotypic marker for stomach adenocarcinoma
116
your patient, who already has metabolic syndrome and PCOS, comes in to you complaining of a velvety, pigmented skin lesion on her axilla - diagnosis?
acanthosis nigricans - caused by excess insulin
117
associations with acanthosis nigricans
(1) metabolic syndrome (2) insulin receptor deficiency
(3) PCOS
(4) MEN type IIb
118
acanthosis nigricans can be a phenotypic marker for..
stomach cancer
119
benign tumor that histologically mimics squamous cell carcinoma
keratoacanthoma
120
keratoacanthoma
rapidly growing, dome-shaped nodules with a central keratin-filled crater that develops in males in sun-exposed areas; usually disappears on its own within 6 months
121
epidermal inclusion cyst
benign cyst composed of normal epidermis of hair follicle that produces keratin intermixed with lipid-rich debris
122
locations of epidermal inclusion cysts
face, base of ears and trunk
123
pilar cyst (wen)
derived from hair root sheaths located on scalp and face - cyst wall lacks stratum granulosum and keratin has laminated appearance
124
flesh-colored tag of skin with a stalk commonly occuring in elderly on neck, upper chest and upper back
fibroepithelial polyp aka skin tag
125
actinic (solar) keratosis is associated with (1) and a precursor to (2)
(1) prolonged UV light exposure (2) squamous cell carcinoma
126
what is actinic (solar) keratosis?
hyperkeratotic, pearly gray-white lesions that occur on face, back of neck and hands/forearms; these lesions commonly recur if scraped off
127
treatment of actinic (solar) keratosis
topical therapy - 5-fluorouracil; cryotherapy
128
MC malignant skin tumor
basal cell carcinoma
129
features of basal cell carcinoma
raised papule/nodule with central crater and telengiectatic vessels that is a locally aggressive and infiltrating cancer (but does not metastasize) and it arises from basal cell layer of epidermis
130
common locations of basal cell carcinoma
inner canthus of eye and upper lip; general rule = favor upper lip and higher
131
risk factors for squamous cell carcinoma (6)
excessive exposure to UV light; actinic (solar) keratoses
| arsenic exposure; scar tissue in 3rd degree burn; orifice of chronically draining sinus tract; immunosuppressive therapy
132
MC cancer complicating immunosuppressive therapy
squamous cell carcinoma of skin
133
common locations of squamous cell carcinoma of skin
ear, lower lip, dorsum of the hands - general rule - SCC favor lower lip
134
prognosis in SCC
good - rarely metastasizes and complete excision is usually curative
135
MC inherited skin disorder
ichthyosis vulgaris
136
ichythosis vulgaris
AD defect in keratinization causing an increased thickness of stratum corneum and absent stratum granulosum
137
clinical findings of ichythosis vulgaris
hyperkeratotic dry skin involving the palms, soles and extensor areas
138
MCC of pruritus and dry skin in elderly
xerosis --> due to decrease in skin lipids
139
age-related changes in the skin of elderly patients
DECREASED: number of hair follicles/sweat glands, thickness of epidermis, dermal collagen/elastic tissue, subcutaneous fat INCREASED: cross-linking of collagen and elastic tissue
140
a black patient comes in with erythematous macules and vesicles that are pruritic and painful; he has not taken any drugs recently and the rash worsens upon exposure to sunlight - diagnosis?
polymorphous light eruption
141
treatment of polymorphous light eruption
broad-spectrum high-potency sunscreen against UVA and UVB along with vitamin E; topical steroids
142
acute eczema
characterized by weeping and erythematous rash with vesicles
143
chronic eczema
dry, thickened skin (hyperkeratosis) caused by continual scratching
144
atopic dermatitis
type 1 IgE mediated HS reaction with dry skin and eczema - in children = cheeks, extensor/flexural surfaces
- in adults = hands, eyelids, elbows and knees
145
allergic contact dermatitis
type IV HS reaction ex. poison ivy, nickel jewelry
146
contact photodermatitis
UV light reacts with drugs that have photosensitizing effect ex. tetracycline
147
chronic cutaneous lupus erythematosus
atrophy of epidermis due to DNA-anti DNA immunocomplex deposition in BM, along with degeneration of basal cells and hair shafts
148
clinical findings in chronic cutaneous lupus
erythematous maculopapular eruption (butterfly rash) that is exacerbated by UV light
149
treatment for chronic cutaneous lupus
antimalarials
150
what is pemphigus vulgaris?
IgG antibodies against IC attachment sites (desmosomes) between keratinocytes = type II HS reaction
151
features of pemphigus vulgaris
(1) vesicles/bullae develop on skin/oral mucosa (2) intraepithelial vesicles located above basal layer
(3) acantholysis of keratinocytes in vesicle fluid
(4) positive Nikolsky sign - outer epidermis seperates from basal layer with minimal pressure
152
treatment of pemphigus vulgaris
corticosteroids and immunosuppressive agents
153
what is bullous pemphigoid?
IgG antibodies against BM - type II HS reaction
154
features of bullous pemphigoid
(1) subepidermal vesicles develop on skin/oral mucosa (2) no acantholytic cells in vesicle fluid
(3) negative Nikolsky sign
(4) presence of eosinophils
155
treatment of bullous pemphigoid
usually subsides after months/years but may require systemic steroids in resistant cases
156
dermatitis herpetiformis
IgA-anti-IgA complexes deposit at tips of dermal papillae forming subepidermal vesicles with neutrophils
157
dermatitis herpetiformis is associated with..
celiac sprue - increase in antireticulin and endomysial ab's
158
treatment of dermatitis herpetiformis
gluten free diet, dapsone or sulfapyridine
159
what is lichen planus?
intensely pruritic, scaly, violet, flat topped papules with fine white reticular pattern on surface (Wickham's striae)
160
Koebner's phenomenon
rash commonly develops in areas of trauma or excessive scratching of the skin ex. lichen planus, psoriasis
161
lichen planus is associated with (1) and slightly increases your risk of (2)
(1) hepatitis C (2) squamous cell carcinoma
162
treatment of lichen planus
topical, high potency corticosteroids, antihistamines, systemic corticosteroids, retinoids, cyclosporine - resistant cases
163
epidemiology of psoriasis
1%-3% of population, peak age onset is bimodal (adolescents and > 60), strong HLA association
164
pathogenesis of psoriasis
unregulated proliferation (hyperplasia) of keratinocytes
165
aggravating factors of psoriasis (4)
(1) strep pharyngitis (2) HIV
(3) drugs: lithium, B-blockers, NSAIDs
(4) scratching the skin
166
what does psoriasis look like?
well-demarcated, flat or elevated salmon-colored plaques covered by adherent white-silver colored scales; majority of patients also have nail pitting
167
microscopic findings in psoriasis
(1) hyperkeratosis and parakeratosis (2) elongation of rete pegs - downward extension of basal layer
(3) Auspitz sign - blood vessels in dermis rupture when scales picked off
(4) munro microabscesses - neutrophil collections in stratum corneum
168
herald patch (plaque) on trunk followed by pruritic rash in "christmas tree" distribution (follows lines of cleavage) that resolves in 2-10 weeks
pityriasis rosea
169
pityriasis rosea is frequently misdiagnosed as..
tinea corporis "ringworm"
170
rash with targetoid appearance located on palms, soles and extensor surfaces
erythema multiforme
171
triggers of erythema multiforme
infection - mycoplasma pneumoniae, HSV. drugs - sulfonamides, penicillin, barbiturates, phenytoin
172
fatal form of EM that involves the skin and mucous membranes
Stevens- Johnson syndrome
173
treatment of EM
systemic corticosteroids - treat triggering infection or discontinue drug
174
raised, erythematous painful nodules usually on anterior shins that are an inflammatory lesion of subcutnaeous fat (panniculitis)
erythema nodosum
175
common associations with erythema nodosum
coccidiomycosis, histoplasmosis, TB, leprosy, strep pharyngitis, Yersinia enterocolitica, sarcoidosis, UC, pregnancy and OCP
176
chronic inflammatory dermal disorder with erythematous papules/plaques on dorsum of hands/feet associated with DM
granuloma annulare - usually spontaneously resolves but can give topic steroids
177
porphyria cutanea tarda
deficiency of uroporphyrinogen decarboxylase (urine is red and uroporphyrin I is increased in urine); precipitated by HCV, excessive alcohol, OCPs and iron
178
CF in porphyria cutanea tarda
photosensitive bullous skin lesions, hyperpigmentation, fragile skin, hypertrichosis - increased body hair
179
treatment of porphyria cutanea tarda
avoid alcohol and OCPs, phlebotomy - decreases iron, chloroquine
180
dermatographism
urticaria develops in areas of mechanical pressure on skin
181
urticaria
pruritic elevations of skin due to mast cell release of histamine (Type I IgE mediated HS reaction) associated with exposure to certain foods, insect bites, drugs, emotional stress
182
cherry angioma
tiny bright red papules that invariably occur in all individuals > 30 years old; no treatment necessary
183
demodex folliculorum causes inflammatory reaction of pilosebaceous units of facial skin with pustules/flushing of cheeks and sebaceous gland hyperplasia resulting in rhinophyma (enlarged nose)
acne rosacea - exacerbated by alcohol, stress, eating spicy food
184
treatment of acne rosacea
topical metronidazole gel. systemic - isoretinoin, tetracycline
185
ulcerative cutaneous condition associated with systemic disease i.e. IBD, MPD, monoclonal gammopathy, seronegative spondylarthropathy, RA
pyoderma gangrenosum
186
pathogenesis of pyoderma gangrenosum
dysregulation of immune system - may be initiated by trauma and neutrophil dysfunction is often present
187
clinical findings in pyoderma gangrenosum
small red pustule/papule that ulcerates and enlarges and is reminiscent of a brown recluse spider bite with violaceous border that overhangs the ulcer crater
188
self-limited benign eruption of erythematous papules, macules and pustules all over (except palms and soles) in full-term newborns
erythema toxicum
189
hyperplastic sebaceous glands producing profuse yellow-white papules in newborns
sebaceous hyperplasia
190
superficial epidermal inclusion cysts forming pearly white papules on face, gingiva and midline of palate and gingiva in newborns
milia - Epstein's pearls (contain laminated keratin material)
191
pinpoint clear vesicles that are sweat occluded in eccrine sweat glands that are usually associated with warm, humid conditions or fever
Miliaria Crystallina
192
retention of sweat in occluded eccrine sweat glands that manifests as erythematous, minute papulovesicles that impart prickly sensation
Miliaria rubra
193
both types of miliaria respond dramatically to..
cooling or removal of excess clothing
194
bluish-black spots that usually occur in dark-skinned babies on their buttocks, back, shoulders and legs
mongolian spot
195
anagen phase of hair growth
development of new shaft of hair comes from hair bulb; growth stops at end of this phase and thus, determines hair length
196
telogen phase of hair growth
resting phase of hair growth where matrix portion shrivels and hair falls out of follicle
197
effect of estrogen on hair growth
causes synchronous hair growth - all hair enters the resting phase at once --> risk for massive hair loss
198
risks for massive hair loss
post partum, OCPs, stress, radiation/chemo
199
well-circumscribed, round-oval patches of hair loss that have the appearance of exclamation marks; regrows over several months but may recur
alopecia areata
200
treatment of alopecia areata
topical - clobetasol, intralesional triamcinolone, systemic steroids, psoralen + UVA
201
nails in iron deficiency
koilonychia - spoon nails
202
nails in psoriasis
pitting
203
mees lines
signs of arsenic poisoning and systemic illness of any kind - transverse white lines in the nail plate that extend proximally until they are pared off
204
Beau's lines
transverse grooves or depression parallel to lunula - caused by conditions that cause the nail to grow slowly (infection, nutritional disorders, hypothyroidism)
205
sunungual hematoma
blood clot under nail plate due to trauma - confused with acral lentiginous melanoma
