Skin Pathology (Gomez) - SRS Flashcards
1
Q
What are these terms all synonyms for?
–skin tags
–acrochordon
–fibroma molle
–squamous papilloma
A
Fibroepithelial polyps
2
Q
What are these?
In what patients are they most common?
What cause are they associated with?
A
Fibroepithelial polyps
- Over 30 and obese in particular
- Associated with areas of rubbing by collar
3
Q
What is shown here?
Describe the histological findings.
A
Epithelial inclusion cyst
Filled with keratinous debris, and lined by squamous epithelium with a granular cell layer.
4
Q
If an epithelial inclusion cyst were ruptured, what would be the result?
A
Will get a foreign body granulomatous giant cell inflammatory reaction to the keratin debris and pain
5
Q
This lesion shows a proliferation of epidermal basal cells, and was round, flat and elevated with a “postage stamp appearance”. These lesions tend to appear on non-exposed skin including the trunk, proximal extremities and lateral neck.
What is this lesion?
A
Seborrheic Keratosis (SK)
6
Q
These lesions all appeared on this patient in a short period of time.
What are these lesions?
What is this sign called?
What is it associated with?
A
Seborrheic Keratosis (SK)
•Sign of Leser-Trélat – malignancies (GI mostly)
7
Q
What percent of adnexal neoplasms are benign?
A
99%
8
Q
What do adnexal neoplasms arise from?
A
ductal and glandular epithelial cells of the adnexa (sweat glands and ducts, hair-bulb germinal epithelium and sebaceous glands, apocrine glands and ducts)
9
Q
Benign adnexal tumors are symmetrical, small (less than 1 cm) superficial and vertically oriented.
How are malignant adnexal tumors different?
A
Asymmetrical, large, deep and wide
10
Q
What are the most common malignant adnexal tumors?
What are a couple of less common ones?
A
Sebaceous carcinoma
Also, eccrine and apocrine carcinomas
11
Q
What type of adnexal neoplasm is this?
How do you know?
A
Sebaceous adenoma/carcinoma
Look for the cells with abundant foamy cytoplasm, this indicates sebum production.
12
Q
What is this adnexal neoplasm?
What do you see on histo?
A
Pilomatrixoma (calcifying epithelioma of Malherbe)
Histo - note the “ghost cells” outlined by green, with progressing apoptosis.
13
Q
What is this adnexal tumor?
What do you see that informs you?
A
Apocrine Hydrocystoma
14
Q
What is this adnexal neoplasm?
How do you know?
Where would it typically be found?
A
Cylindroma - a benign tumow of sweat glands
- found on the forehead and scalp
Identify based on the nests of basaloid cells that fit like a jigsaw puzzle
15
Q
What is this adnexal neoplasm?
Where would it be found?
What are you picking up on histologically?
A
Trichoepithelioma - tumor arising from hair follicle
Note the amorphous keratin blobs, these are hair follicles
16
Q
If you see a patient with numerous lesions with this appearance, what clinical syndrome should you be considering?
What is the inheritance pattern?
A
Cowden syndrome - Multiple tricholemmomas with dominant inheritance
17
Q
If you find a number of these type of lesions in a patient with colorectal malignancies, what should you consider in the differential?
A
Muir-Torre Syndrome:
Sebaceous adenomas with association colorectal malignancy (variant of Lynch)
18
Q
If you see a patient with a massive confluence of this type of tumor what condition should you be thinking of?
A
Turban tumor : Massive confluent cylindromas
19
Q
What color are these Dermal lesions?
Hemangioma
xanthomas
Fibrohistiocytic lesions
A
- Hemangioma - Red
- Xanthomas – Yellow
- Fibrohistiocytic lesions – normal tan-brown skin tone or darker
20
Q
What type of hemangioma is this?
A
Lobular capillary hemangioma
21
Q
What type of hemangioma is this?
A
Cavernous hemangioma
22
Q
This lesion is common to young, middle age women, and may occasionally be tender.
What is it?
A
Benign Fibrous Histiocytoma (Dermatofibroma)
23
Q
What is increased in these pigmented conditions?
–Sun tan
–Freckles
–Café au lait spots
–Melasma
A
•Increased melanin in keratinocytes: NO increase in number of melanocytes
24
Q
What is a condition in which there is Increased melanin in keratinocytes and a small increase in number of melanocytes?
A
Solar Lentigo
25
What are two conditions where there is a loss of melanin in keratinocytes?
–Acute transient vitiligo
–Albinism
26
What is an example of a condition where there is a loss of melanocytes?
Chronic vitiligo
27
What are the two names for these?
Freckles - Ephelides
28
What is a large freckle called?
Cafe-au-lait spot
29
Based on the attached findings what does this person have?
What are the attached findings?
Neurofibromatosis Type 1
## Footnote
Cafe au lait spots
Lisch Nodules on the Iris (melanotic hamartomas)
30
What is mutated in Neurofibromatosis Type 1?
What are the physical manifestations common to patients with this autosomal dominant disorder? 8
NF1
1. Neurofibromas (Including plexiform)
2. Malignant sheath tumors
3. Cafe au lait spots
4. freckles in axilla
5. optic nerve glioma
6. Lisch Nodules on Irirs
7. Macrocephaly
8. Scoliosis
31
In which type of neurofibromatosis do you see deafness?
Type 2
32
What is shown here?
Melasma (Chloasma)
“Mask of Pregnancy”
33
Melasma occurs in women far more than men and is a blotchy hypermelanosis on face with symmetrical distribution over the cheeks and forehead and appears less frequently on upper lip and neck.
In what three situations does this occur?
1. During pregnancy
2. In women taking oral contraceptives
3. At menopause
34
If I say... Epidermal hyperplasia of stratum spinosum & hyperpigmentation... you say that is?
What conditions is this associated in the young?
In the old?
Acanthosis nigricans
Young - DM
Elderly - malignancies
35
What is shown here?
Acanthosis Nigricans
36
What percent of acanthosis nigricans is paraneoplastic?
What cancer type is this mostly associated with?
20% - associated with adenocarcinoma
37
What is solar lentigo?
•Benign, discrete hyperpigmented macule on chronically sun exposed skin
–Back of the hands and the forehead
–In adults
38
Describe the number of melanocytes and degree of pigment in keratinocytes seen in lentigo simplex
Solar Lentigo (Lentigo Senilis, Lentigo Simplex)
* melanocytes: variable increase
* melanin pigment in keratinocytes: increased
39
What does lentigo maligna refer to?
In situ melanoma arising in sun exposed skin
40
What are the nests seen in Junctional melanocytic nevi?
Basal epidermal nests
41
What are the nests seen in compound melanocytic nevi?
Basal epidermal and dermal nests
42
What are the nests seen in intradermal melanocytic nevi?
Dermal nests
43
What mutations are commonly seen in melanocytic nevi?
NRAS and BRAF (induce melanocyte metaplasia short of malignancy)
44
What is the four stage natural history of nevi?
1. Junctional
2. Compound
3. Intradermal
4. Neurotized
45
This nevus shows Melanocytes change appearance from epithelioid to spindled shape. What stage of nevus is it?
IV - Neurotized
46
This nevus shows Nests of melanocytes present only in the dermis. What stage is it?
III - Intradermal
47
This nevus shows Nests of melanocytes at base of the epidermis and in the dermis. What stage nevus is it?
II - Compound
48
This nevus shows Nests of melanocytes along base of the epidermis. What stage is it?
I - Junctional
49
Type of Nevus?
Compound type
50
Type of Nevus?
Junctional type
51
What is this depigmented nevus?
Is it hard or rubbery?
Intradermal melanocytic nevus
Rubbery since not malignant and no desmoplastic rxn
52
These nevi are giant congenital nevi.
Are they benign or malignant?
What would you see histologically?
* Benign, but melanoma can arise in the larger congenital nevi
* Extensive deep dermal to subcutaneous growth with proliferative nodules
53
What is this?
Blue nevus
54
This red lesion shows characteristicraining down melanocyte pattern and Kamino bodies (eosinophilic amorphous globules). What should be done with it?
What is it?
Spitz nevus - cut it out since it is very difficult to distinguish from melanoma
55
If you see a red raised lesion in a child or young adult and find it has a spindle and epitheliod appearance, what is it?
Spitz Nevus = Spindle & Epithelioid Cell Nevus
56
Describe this halo nevus.
•Involuting (regressing) nevus with extensive lymphocyte infiltration and depigmentation of surrounding skin
57
What are the pre-malignant and malignant lesions we covered this day? 7
I.Dysplastic nevi and malignant melanoma
II.Actinic keratosis
III.Squamous cell carcinoma
- Keratoacanthoma type
IV.Basal cell carcinoma
V.Dermatofibrosarcoma protuberans
- Bednar tumor
VI.Leukemia/lymphoma
VII.Mastocytoma
58
In this sample you find the **rete ridges are bridged** (connected at their bases) and **reactive fibrosis of the papillary dermis.** What is this lesion?
What are the two situations where these arise and in which case is it prone to malignancy?
Dysplastic (Clark) Nevus
Sporadic - not prone to malignancy
Famillial - dysplastic nevus syndrome: 50% chance of melanoma by 60
59
What are the two growth phases of this melanoma?
* Superficial spreading - invasive, mostly horizontal growth phase
* Nodular - invasive, mostly verticle growth phase
60
Melanoma occurs primarily in adults beginning in the 3rd decade. 90% originate de novo as an isolated lesion, but they can arise adjacent to a pre-existing melanocytic nevus. It is an aggressive malignancy that metastasizes widely with significant mortality.
Where does it tend to metastasize to?
Regional Lymph nodes, liver, lungs and brain
61
What are the main risk factors for malignant melanoma? 4
* Caucasians with fair skin
* Prolonged MCB UV exposure with repeated sunburn
* 3 episodes of “peeling” or severe sunburn before age 20
* Male gender
62
What mutated gene is seen in 70% of skin melanomas?
Mutated TERT gene
63
Melanoma?
Yup
64
What is the most important predictor of outcomes in melanoma?
Depth of invasion
65
What is the best measurement for staging melanoma?
Breslow level (thickness from epidermal granular layer to deepest dermal penetration
66
What is the 10 year survival for melanoma with the following thicknesses?
\< 1.00 mm
1. 01 to 2.00 mm
2. 01 to 4.00 mm
\> 4.00 mm
\< 1.00 mm = 92%
1. 01 to 2.00 mm = 80%
2. 01 to 4.00 mm = 63%
\> 4.00 mm = 50%
67
What would you call a lesion with the following description?
## Footnote
–Permanent, incremental damage to reticular collagen (elastosis)
–Loss of normal skin texture (leathery and wrinkled)
Solar elastosis
68
What would you call a lesion with this description?
## Footnote
–Focal autonomous overproduction of melanosomes
–Resultant sustained increase in melanin in keratinocytes
Solar Lentigo
69
Actinic Keratosis is also known as solar keratosis, senile keratosis and keratinocytic intraepidermal neoplasia. What do these precancerous lesions look like?
•Erythematous, reddish-brown macules or minimally elevated papules with overlying scale and variable shape.
70
Where does actinic keratosis tend to arise on the body?
In what age ranges?
•Middle-aged and elderly individuals
–Face, particularly forehead
–Neck
–Dorsum of arms and hands
–Lips (actinic cheilitis)
71
What is shown here?
What do you see on histology?
Actinic Keratosis
72
Squamous cell carcinoma is a malignant proliferation of what?
Epidermal keratinocytes
73
What are the primary etiologies of SCC?
* UVB wavelengths (280 – 315 nm) are the most carcinogenic
* Immunosuppression increases incidence of invasive SCC (d/t T cell decreases)
74
What are some other etiologic agents associated with Squamous cell carcinoma?
* Human papillomavirus (HPV)
* Chronic skin inflammation, ulcers and draining fistulous tracts (osteomyelitis)
* Some dermatoses
* Burns
* Ionizing radiation
* Chemical exposures
–Tars → scrotal cancer in chimney sweeps
–Arsenic ingestion
–Tobacco and betel nut usage
•
•Genetic syndromes
–Epidermodysplasia verruciformis (predisposition to HPV infections and HPV subtypes 5 and 8 can lead to SCC)
–Xeroderma pigmentosa (nucleotide excision repair pathway defects)
–Other syndromes
75
What is this lesion?
Describe the typical course of its presentation.
Keratoacanthoma or, the better term..."Squamous cell carcinoma, Keratoacanthoma type”
## Footnote
**•Rapidly growing (days-weeks)**
**•Often involutes and clears spontaneously within 3 to 4 months**
76
Basal cell carcinoma is a malignant neoplasm of what?
Basal regenerative epithelium of the epidermis
77
Basal cell carcinoma almost never metastasizes, and has numerous subtypes.
What are the types we discussed?
Nodular
Sclerosing
Multifocal superficial spreading
78
Most basal cell carcinomas have a mutation that leads to unbridled signaling in what path?
Hedgehog pathway
79
What is the advanced presentation of this basal cell carcinoma referred to as?
Rodent ulcer
80
What are the characteristic signs of Nevoid Basal Cell Carcinoma Syndrome (Gorlin Syndrome)? 5
1. •Multiple basal cell carcinomas before age 20
2. •Pits of the palms and soles
3. •Odontogenic keratocysts
4. •Medulloblastomas
5. •Ovarian fibromas
81
Gorlin syndrome is an autosomal dominant disorder with what mutations?
1. PATCH1 gene mutation (GOF) leading to constitutive SMO action
2. Gain of function SMO mutation
82
What is this lesion?
How do you know?
**_Nodular Basal Cell Carcinoma_**
* Traditional or “classic” appearance of BCC
* Dome-shaped, **pearly papule or nodule**
* Prominent surface **_dilated dermal vessels (telangiectasia_**)
83
What is this waxy yellowish-white or pearly white, indurated plaque that retracts below plane of skin surface and occurs mostly on the face?
What do Tx outcomes look like?
Sclerosing (Morpheaform) BCC
## Footnote
–Difficult to excise, high recurrence rate and may disfigure
–Mohs surgery can be used during excision to determine complete excision
84
This lesion shows multifocal erythematous, scaly plaque; elevated rolled edges, and may be part of a field defect, thus can recur post excision.
What is it?
Where does it occur on the body?
Superficial BCC
## Footnote
•Occurs **non-sun exposed skin sites** on proximal limbs or trunk
85
What is this malignant superficial fibroblastic neoplasm called?
How about the pigmented version specifically?
Dermatofibrosarcoma Protuberans
## Footnote
–**Bednar tumor** is pigmented variant
86
What is the translocation in dermatofibrosarcoma protuberans?
–Translocation of COL1A1 and PDGFB → ↑PDGFB
87
What does this skin tumour appear to be?
Lymphoma - probably a T cell lymphoma since those tend to go for skin
88
On closer inspection of the lymphoma patient seen in the last question you find these cells flouating in the patients blood stream.
What does this patient have?
Mycosis Fungoides
More specifically, Sezary syndrome with a leukemic phase - indicated by the presence of Sezary cell (cerebriform nuclei)
89
What are the phases of mycosis fungoides?
–Inflammatory erythrodermic pre-mycotic patch
–Plaque
–Tumor
90
What are the cell surface markers seen in mycosis fungoides?
CD4+ T-cell lymphoma of the skin (CLA, CCR4 & CCR10)
91
What does Sezary syndrome look like on gross inspection?
manifest as a generalized exfoliative erythroderma
92
What is the lesion shown here?
What sign might be associated with it?
Mastocytosis/Mastocytoma
Darier Sign - stroking of the skin leads to histamine release which causes swelling, erythema and edema
93
What are the 7 categories of dermatoses?
1. Acute inflammatory
2. Chronic inflammatory
3. Blistering (bullous) diseases
4. Panniculitis
5. Infection
6. Infestation
7. Non-inflammatory
94
What are the acute inflammatory dermatoses? 3
A.Urticaria (hives)
B.Eczema
C.Erythema multiforme
95
What are the chronic inflammatory dermatoses? 7
A.Seborrheic dermatitis
B.Psoriasis
C.Lichen simplex chronicus
D.Lichen planus
E.Discoid lupus erythematosus
F.Rosacea
96
What are the three blistering dermatoses?
A.Pemphigus
B.Bullous pemphigoid
C.Dermatitis herpetiformis
97
What are the two panniculitis dermatoses?
A.Erythema nodosum
B.Erythema induratum
98
What are the three types of acute urticaria?
1. Mast cell and IgE dependent
2. Mast cell dependent but IgE independent
3. Mast cell and IgE independent
99
What type of urticaria would contrast media cause?
1.Mast cell dependent but IgE independent
100
What type of acute urticaria would Hereditary angioneurotic edema (C1-inhibitor deficiency) produce?
How do you treat this?
1.Mast cell and IgE independent
(With known C1 inhibitor deficiency use C1 inhibitor (C1-INH) concentrates, kallikrein inhibitor or fresh-frozen plasma)
101
Acute urticaria may present with wheals and bullae. What are these two things?
–Wheal: Transient edematous erythematous plaque secondary to an acute allergic reaction
–Bullae: Larger fluid-filled lesions
102
What is shown in these images?
Eczema =
Spongiotic Dermatitis
103
What is Eczema?
What is it usually driven by?
* Dermatitis with intercellular epidermal edema and prominent lymphocytes in dermis and epidermis
* Usually driven by T cell mediated type IV hypersensitivity inflammation
104
Erythema Multiforme is a Hypersensitivity (CD8+ cytotoxic T cells) reaction to drugs, infections, malignancy, collagen vascular disorders.
What are some infections known to do this?
–Infections: herpes simplex, deep fungal (histoplasmosis), Salmonella typhi, leprosy
105
Erythema Multiforme is a Hypersensitivity (CD8+ cytotoxic T cells) reaction to drugs, infections, malignancy, collagen vascular disorders.
What are some drugs known to do this?
–Drugs: antibiotics, salicylates, anti-malarials
106
What are these lesions?
Erythema Multiforme - characteristic "target" lesions (red - pale - red)
107
What are two pathological conditions similar to Erythema Multiforme?
–Stevens-Johnson syndrome: Severe, systemic disease with atypical targetoid skin lesions that become bullous +/- oral and ocular involvement
–Toxic epidermal necrolysis: has diffuse necrosis and sloughing of skin and mucosae
108
psoriasis is a systemic disease that causes a chronic skin condition. The typical lesions will be well demarcated, pink to salmon plaques involving the elbows, knees, scalp, lumbosacral area, intergluteal cleft, and glans penis.
What is the phenomenon associated with this?
The "sign"?
Koebner phenomenon – trauma can induce skin lesions
Auspitz sign – scrape off scale and get punctate hemorrhages
109
Psoriasis is associated with HLA-Cw\*0602. What does this lead to?
•increased CD4+TH1 sensitized cells set off other T-cells causing increased cytokines leading to epidermal proliferation.
110
What is this lesion shown here?
What is the give away on histology?
Psoriasis
Munro microabcess
111
Lichen simplex chronicus is essentially a callus from rubbing or scratching. What is it called if nodular?
Prurigo nodularis
112
Seborrheic dermatitis involves skin regions with high density of sebaceous glands (oil or sebum production) such as the Scalp, forehead, especially glabella (space between eyebrows), nasolabial folds, auditory canals, intergluteal fold. Excessive dandruff on scalp is common.
Infection with what organism is associated with this?
Malassezia Furfur
113
Lichen planus is a Self-limiting chronic inflammatory condition of skin and oral mucous membranes with multiple plaques that are symmetrically distributed, often on wrists and elbows and on the glans penis, + Koebner phenomenon. This typically resolves after 1-2 years but may persist in the oral cavity.
What are four things you'll see/hear (buzz words) regarding lichen planus?
1. Wickham Striae
2. Sawtoothing
3. Lichenoid infiltrate
4. Civatte/colloid bodies
114
What is this?
Cutaneous Lupus Erythematosus (CLE) - localized cutaneous manifestations like those of systemic lupus erythematosus (SLE) but with no SLE systemic manifestations
115
Malar erythema is characteristic of CLE (and SLE), what are the chronic subtypes?
Describe each.
* Discoid - coin-like scaling plaques
* Tumid – juicy red papules and plaques
* Lupus panniculitis/profundus – painful subcutaneous nodules
116
What is the immunofluorescence against in this positive lupus band test?
IgG or C1
117
What patter of deposition is seen in a positive band test for lupus?
Granular deposits of antigen-antibody complexes and complement at the dermoepidermal junction
118
Rosacea is fairly common, especially in 30 - 60 year old females. What are the stages? 4
–Pre-rosacea (flushing)
–Erythematotelengiectatic
–Papulopustular
–Phymatous
119
Identify the blistering/bullous diseases that arise at each of these sites.
Superficial desmosomes - Pemphigus Foliaceus
Deeper desmosomes - Pemphigus vulgaris
Hemidesmosomes - bullous pemphigoid
120
What is attacked in pemphigus foliaceus?
Where does the blister arise?
Desmoglein 1
Subcorneal blister
121
What is attacked in pemphigus vulgaris?
Where does the blister arise?
Desmoglein 1 and 3 (mostly 3)
Suprabasal blister
122
What is attacked in bullous pemphigoid?
Where is the blister?
BPAG1 and BPGA2
Subepidermal blister
123
What is attacked in dermatitis herpetiformes?
Where is the blister?
Reticulin in anchoring fibers
Subepidermal blister
124
The pemphigus group of diseases are autoimmune skin diseases where IgG autoantibodies are formed against desmosomes (spinous processes) of squamous epithelial cells.
Describe pemphigus vulgaris and foliaceus as far as where on the body they arise.
–Pemphigus vulgaris (80%): Involves mucosa and scalp, face, axilla, groin and other pressure points; classic bullous disease
–Pemphigus foliaceus: more benign course; involves face, scalp, chest and back and spares mucous membranes
125
In what type of cancer do we most often see paraneoplastic pemphigus?
Lymphoma
126
What is being attacked in this condition?
What is the condition?
Pemphigus Foliaceus
Desmoglein 1
127
Pemphigus foliaceus typically has a more benign course, and involves what 4 areas?
What does it specifically spare?
_Involves_
1. Scalp
2. Face
3. Chest
4. Back
_Spares_
1. Mucous membranes
128
What is this condition?
What is the target of the attack?
Pemphigus Vulgaris
Desmoglein 1 and 3 (mostly 3)
129
What is the autoantibody against in this condition?
Are these lesions easy or difficult to pop?
Bullous Pemphigoid
Autoantibodies to hemidesmosomes
Difficult to pop
130
Where in the skin layers would you see a bullous pemphigoid arise?
Subepidermal blister
131
What specifically are the anti hemidesmosomes against in bullous pemphigoid?
BPAG1 and BPAG2
132
This rare skin bullous disorder afflicts men more than women and arises typically in the 3rd and 4th decades. What is it?
Dermatitis herpetiformis
133
What strain of Herpes is responsible for dermatitis herpetiformis?
None, it is not involved
134
What condition is dermatitis herpetiformis often associated with?
Celiac disease
135
What are the antibodies against in dermatitis herpetiformis?
IgA to gliadin attacks the reticulin in dermal papillae fibrils.
136
How does dermatitis herpetiformis present clinically?
•Intensely pruritic plaques and vesicles on Extensor surfaces, elbows, knees, upper back and buttocks.
137
What layer will dermatitis herpetiformis hit below?
The basal cell layer
138
What are the two main types of panniculitis?
What are the other three types?
1. Erythema nodosum
2. Erythema induratum
Also, Weber-Christiansin disease, factitial panniculitis and cutaneous lupus profundus/panniculitis)
139
What kind of pannicultitis is erythema nodosum?
Acute septal panniculitis
140
What is the acute septal panniculitis in erythema nodosum associated with?
_Infections_
1. TB
2. Beta-strep
_Sarcoidosis_
_IBD_
_Malignancies_
_Drugs_
1. oral contraceptives
2. sulfonamides
141
What type of panniculitis is erythema induratum?
Lobular panniculitis
142
Verruca Vulgaris is common in children and adolescents, and appears as what kind of lesions?
–Distinct, gray-white to tan 0.1 to 1.0 cm papules or plaques in skin
143
What is verruca vulgaris d/t?
HPV subtypes 2 and 4
144
Whats a buzz term you might hear with verruca vulgaris?
Firm, cobble-stone feel
145
What are the characteristics of verrucae plantaris and palmaris?
Elongated, broad and flat and larger than 1-2 cm plaques
146
Condyloma acuminatum is verruca vulgaris of the anogenital region. What HPV types are associated?
6 and 11
147
What condition is shown here?
Molluscum contagiosum
148
Molluscum contagiosum is a common, self limited viral disease spread by direct contact and caused by what virus?
Pox Virus
149
What is shown here?
Molluscum bodies - Molluscum contagiousum
150
Acne Vulgaris is a chronic smoldering infection of the hair follicle by?
lipase producing Propionibacterium acnes.
151
Retin A is often used to treat acne vulgaris, how does it do its job?
Alters the chemical composition of the sebum of the hair follicle to P. acnes cannot use it as a nutrient.
152
What type of antibiotic is commonly employed to treat acne vulgaris?
Minocycline
153
What are the two types of this condition and in what way do they differ?
* Impetigo contagiosa
* Impetigo bullosa
Differ predominantly in the size of the pustule
154
What is currently the number one organism in each subtype of impetigo?
S. Aureus
155
Historically, what organism is most often associated with each...
Impetigo contagiosa
Impetigo bullosa
?
* beta-Streptococcus in contagiosa
* Staphylococcus aureus in bullosa
156
Dermatophytes often infect the skin, what layer is this infection confined to?
Stratum corneum of the epidermis
157
Define...
## Footnote
–Tinea capitis:
–Tinea corporis (ringworm):
–Tinea cruris:
–Tinea pedis (athlete's foot):
–Tinea barbae:
–Tinea capitis: scalp in children
–Tinea corporis (ringworm): trunk and extremities in all ages but more in children
–Tinea cruris: inguinal skin adjacent to genitalia
–Tinea pedis (athlete's foot): feet between toes
–Tinea barbae: beard area in men
158
What are the main ways that arthropods can cause pathology in humans?
1. **Direct injury by insect part/secretions**
* Mosquitoes, chiggers, et.
2. **Acute or delayed hypersensitivity reaction**
* Bee/wasp stings, etc.
3. **Direct toxin effect**
* Brown recluse spider, etc.
4. **Vector for other disease transmission**
* Mosquitoes: malaria, West Nile virus, dengue, etc.
* Ticks: Lyme disease, Rocky Mountain spotted fever, etc.
159
What are the 3 non-inflammatory dermatoses?
Ichthyosis Vulgaris
Epidermolysis bullosa
Porphyrias
160
What is shown here?
What is usually the cause?
Ichthyosis vulgaris:
hyperkeratosis with “fish-scaling”, usually genetic abnormalities
161
This kid has a genetic abnormality of structural proteins leading to massive bullae, what is this condition?
Epidermolysis bullosa
162
