INVESTIGATIONS & TREATMENTS IN DERMATOLOGY Flashcards
(165 cards)
1
Q
List 7 conditions which WOOD’S LIGHT is used for
A
Pseudomonas infections Porphyrins Ptyriasis versicolor Erythrasma Tuberous sclerosis Tetracycline stains in teeth Vitiligo (low grade) Fungal infections Mepacrine stains in nails
2
Q
List 2 conditions in which DIASCOPY is used for
A
Erythematous lesions
Granulomatous lesions – apple jelly nodule
3
Q
PARTS OF A DERMATOSCOPE?
A
Magnifier (x10 magnification) and Non-polarized light source
4
Q
What’s a DERMATOSCOPE used for?
A
To diagnose pigmented lesions in vivo
5
Q
How is DERMATOSCOPY done?
A
Cover up lesion with mineral oil, water or alcohol
Illuminate
Observe at x10 magnification
6
Q
What is a DERMATOSCOPE particularly used to diagnose?
A
Malignant melanomas and pigmented skin lesions
Others - scabies mites in their burrows
7
Q
List 7 methods of specimen gathering
A
Blood films Hair brushings Aspiration Nail clippings Swabbing SKIN(Stratum corneum)scrapings Skin biopsy Stool sampling
8
Q
What is swabbing used for?
A
For ulcerations and abscesses as in impetigo
9
Q
What is aspiration used for?
A
For intact vesicles, pustules, and Bullae.
After gentle sterilization of surface with alcohol
10
Q
What is skin scraping/nail clipping majorly used for?
A
Dermatophyte infections
11
Q
What skin disorders can SKIN biopsy be used for
A
Mycoses fungoides
Cutaneous T-cell lymphoma
12
Q
When are HAIR BRUSHINGS used for?
A
To obtain material for fungal culture in SUSPECTED SCALP LESIONS
13
Q
When do we obtain STOOL SAMPLES?
A
To check for oval and parasites in cases of FILARIASIS e.g onchocerciasis and loa loa
14
Q
Why do we obtain BLOOD FILMS?
A
To check for Blood micofilaria
15
Q
What time do we take blood films for Loa loa and elephantiasis
A
Los loa - 12:00 noon
Elephantiasis - 10:00 - 2:00am
16
Q
What determines the time to take a BLOOD FILM?
A
Depends on the species involved and feeding pattern of the athropods
17
Q
What color will FUNGAL INFECTIONS show on wood’s light?
A
greenish yellow
18
Q
What color will ERYTHRASMA show on wood’s light?
A
Coral pink
19
Q
What color will PSEUDOMAONAS PYOCYANAE show on wood’s light?
A
Yellow green
20
Q
What color will PORPHYRINS show on wood’s light?
A
Bright red
21
Q
Outline 10 LABORATORY TESTS used in Dermatology
A
Skin snip Histology Electron microscopy Microscopic examination Culture Skin/surgical biopsy Prick test Patch test Immunoflourescence DIASCOPY DNA probes Wood's light examination
22
Q
Mention 3 dermatological conditions diagnosable by LIGHT MICROSCOPY?
A
Scabies
Pediculosis
Fungal infections( Tinea and candidiasis)
23
Q
Mention 3 dermatological conditions diagnosable by ELECTRON MICROSCOPY
A
Herpes simplex e.g Eczema herpeticum in babies and Viral warts
Blistering diseases e.g Epidermolysis bullosa
Genodermatosis
24
Q
DERMATOSCOPY is otherwise known as what?
A
Dermoscopy or Epiluminoscopy or Epiluminescent microscopy
25
```
What type of preparation is done for the following skin lesions?
SCALE
PUSTULE/BULLAE
VESSICLE
INDURATED ULCER
```
SCALE - KOH Prep
PUSTULE/BULLAE - KOH prep/Gram stain
VESSICLE - Tzanck Prep
INDURATED ULCER - dark field examination(Suspected syphyllis)
26
What is the commonest preparation done?
KOH prep
27
What is the 2nd commonest preparation done?
TZANCK prep
28
Outline the 1st step you would take in preparing a KOH mount for a Dermatophytic infection?
I'll vigorously scrape the scales from the edge of the scaling lesion using a no 15 scalpel blade carefully avoiding very thick pieces of scale as they would be difficult to examine
29
Outline the 2nd step you would take in preparing a KOH mount for a Dermatophytic infection
I'll place 1-2 drops of KOH(20%) on the scale before covering with cover slip
30
Outline the 3rd step you would take in preparing a KOH mount for a Dermatophytic infection
If immediate examination is required, I'll gently heat the slide over an alcohol lamp until the bottom of the slide feels quite warm to the touch
(AVOID BOILING)
31
Outline the 4th step you would take in preparing a KOH mount for a Dermatophytic infection
I'll firmly press a paper towel on top of the cover slip or slide
32
Outline the 5th step you would take in preparing a KOH mount for a Dermatophytic infection
I'll then examine the preparation under light microscope using low illumination
33
Outline the 6th step you would take in preparing a KOH mount for a Dermatophytic infection
I'll then scan the entire cover slip under low power looking for the hyphae which sometimes appear refractile in the cellular areas
34
What do you do if suspicious elements are seen under low power?
I'll use the high dry objective lens to examine
35
Outline the final step you would take in preparing a KOH mount for a Dermatophytic infection
I'll send samples for culture
36
What's the essence of the 4th step in KOH mount preparation
It spreads the cells into a thin layer on the slide as a monolayer of cells are desired in microscopic examination
Blotting gets rid of excess KOH on and around the cover slip
37
What % of KOH is used for skin scrapings?
10%
38
What % of KOH is used for T. Corporis?
10%
39
What % of KOH is used for nail clippings?
20-30%
40
What % of KOH is used in Onychomycosis?
20-30%
41
What is the rationale for using KOH in Dermatophytic infections prep?
KOH dissolves the keratin thus allowing hyphae to be identified
42
If KOH contains ______, Ptyriasis vesicolor will show it's characteristic _______ appearance
Indian ink
| Spaghetti and meatballs
43
DIRECT immunoflourescence detects what?
Antibodies(IgG) in a patient's skin
44
Outline 5 dermatological conditions in which DIF would confirm the diagnosis?
```
Pemphigus vulgaris
Bullous pemphigoid
Dermatitis herpetiformis
SLE
DLE
```
45
INDIRECT immunoflourescence detects what?
Antibodies(IgG) in a patient's serum
46
Outline 4 dermatological conditions which can be diagnosed using TZANCK preparation?
Herpes simplex
Herpes zoster
Varicella zoster
Pemphigus vulgaris
47
What component of the blister is sample obtained in a TZANCK preparation?
The BASE of the blister is gently scraped
48
What stain is used in a TZANCK preparation
Giemsa or Wright stain
49
What will herpes zoster, herpes simplex and Varicella zoster show on TZANCK prep?
Multinucleated giant cells
50
What viral infections will not be seen on TZANCK prep?
Vaccinia(cow pox)
| Small pox
51
What will pemphigus show on TZANCK prep?
Acantholytic cells
52
What are the most frequently sought organisms in CULTURE?
Fungi and bacteria
53
What specimen is required in superficial(dermatophytic) fungal infections?
Skin scrapings
54
What specimen is required for deep fungal infections?
Skin tissue
55
What specimen is required for T. Corporis?
Skin scrapings
56
What specimen is required in Histoplasmosis?
Skin tissue
56
What specimen is required in Histoplasmosis?
Skin tissue
57
How is skin specimen obtained in deep fungal infections?
Via a deep punch biopsy from the active border of the lesion
58
Viruses cannot be cultured in vesicular lesions (T/F)
False.
| Viral cultures can be obtained in vesicular lesions
59
What important thing must be done simultaneously during CULTURE prep?
Tissue must be sent simultaneously to pathology laboratory for histological examination
60
Scrapings for culture are inoculated into what agar medium?
Sabourauds dextrose agar (glucose +peptone)
61
Bacteria growth in agar medium is prevented by?
Adding antibiotics (penicillin)
62
Saprophytic mould growth in agar medium is prevented by adding?
Cycloheximide
63
Culture may be continued for how long?
3 weeks
64
Outline 2 dermatological conditions that can be diagnosed with the aid of SKIN SNIPS/SMEARS
Onchocerciasis
| Leprosy
65
Mention 3 drawbacks in the use of SKIN SNIPS?
It's painful
Requires appropriate sterilization
May fail to diagnose light infections
66
Skin smears in leprosy are stained using what method?
Modified acid fast method
67
The site for skin slits do not necessarily have to be cleaned with alcohol before taking samples (T/F)
False
68
Outline 2 drawbacks of skin/surgical biopsy?
Taken under local anaesthetic (lignocaine +/- adrenaline)
| Unhelpful in conditions without a specific histology e.g most drug eruptions
69
Outline the 2 main types of SKIN BIOPSY?
EXCISIONAL
| INCISIONAL
70
When is EXCISIONAL biopsy preferable?
For most small lesions up to 0.5cm in diameter
71
When is INCISIONAL biopsy chosen?
When partial removal of a larger lesion is adequate for diagnosis
Complete removal might leave an unnecessary and unsightly scar
72
Outline 2 dermatological conditions in which PATCH TEST can be utilized?
Allergic contact dermatitis
| Hand eczema
73
Which skin site is preferred when carrying out PATCH TEST?
The Back (cos it's really thick)
74
When is the 1st and 2nd reading taken respectively when carrying out patch test?
48hrs and 96hrs respectively
75
What type of hypersensitivity rxn does the PATCH TEST detect?
Type IV Hyps rxn
76
What universal precaution must be ensured when carrying out a patch test?
Patch test material should be at a concentration adequate to elicit allergy but not high enough to be an irritant
77
What skin layer is utilized in intradermal injection
Superficial layer of the dermis
78
What size of injection needle is used for intradermal injection
Size 26 or 27 guage
79
What skin site is preferred for intradermal injection?
Ulnar surface of the forearm (it's a more sensitive site)
80
What wheal diameter can be relied upon in intradermal injection
Wheal diameter above 4mm to 15mm
81
The PRICK TEST is a modified form of intradermal injection (T/F)
TRUE
82
What hypersensitivity rxn type does the PRICK TEST detect?
Type 1 hyps rxn(immediate)
83
How long after introduction of commercially prepared antigen should wheal be observed in prick test?
10mins
84
What needle size is used in the prick test
25 guage
85
What comprises the positive and negative control in the PRICK TEST?
Positive control - Histamine
| Negative control - Antigen diluent
86
______ inhibits the magnitude of the rxn in the PRICK TEST?
Systemic antihistamines
87
What universal precaution must be ensured when carrying out a PRICK TEST?
RESUSCITATION must be available since systemic rxns may develop in ptx with clear hx of type 1 hyps rxn
88
Immediate weal tests are carried out to detect what?
IgE antibodies
89
Immediate weal tests are use primarily in assessing atopic dermatitis (T/F)
False.
| Immediate weal tests are used principally in assessing hay fever and asthma but have limited space in mgt of asthma
90
Systemic rxns never occur when standard solns are used in immediate weal tests (T/F)
False.
| Systemic rxns may occur with the correct use of standard solns
91
Tuberculin/mantoux test is a PRICK TEST? (T/F)
False.
| It's an INTRADERMAL TEST
92
Mantoux test is done to know if a person is immune to TB or not (T/F)
False.
| It's HEAF TEST
93
HEAF TEST can be done before or after vaccination for TB (T/F)
False.
| HEAF TEST is done prior to vaccination
94
Where is the preferred skin site for a Mantoux test
The fore arm
95
The online visual exchange of clinical and histological data is known as what?
TELEDERMATOLOGY
96
Outline 2 dermatological conditions in which ORAL PROVOCATIVE TESTS can be employed?
Atopic dermatitis
| Chronic urticaria and angioedema
97
Outline 4 components used in diagnosis of HIV by serology?
Detection of HIV-antibodies in serum of ptx
Detection of HIV-antigens (p24)
Detection of HIV nucleic acids
Viral culture
98
Mention 2 serological tests for detecting hiv-antibodies in ptx serum
```
Double ELISA(Enzyme linked immuno-absorbent assay)
Western blot
```
99
How is HIV-nucleic acid detected via serology
```
Using PCR(Polymerase chain rxn)
DNA-PCR and RNA-PCR
```
100
What serological tests is used to screen for syphyllis?
VDRL (venereal disease research laboratory)
| RPR (rapid plasma reagin)
101
What does the VDRL TEST measure?
It measures the antibody produced in response to Treponema pallidum
102
What specimen is the VDRL test carried out on? And what does the antibodies detected react to?
```
BLOOD and CSF
diphosphatidyl glycerol (an extract from Oxford heart)
```
103
What does the VDRL test detect? And how is it visualised?
Detects ANTI-CARDIOLOIPIN Ab (IgG, IgA, IgM)
| Visualised via flocculation (foaming of a test tube fluid)
104
The VDRL test detects syphyllis in all stages (T/F)
False.
| VDRL test is positive in secondary and latent syphyllis
105
A positive VDRL test may be confirmed with what?
FTA-ABS (Fluorescent Treponema Antibody- ABSorption)
| A more specific test
106
Outline 10 causes of VDRL false positive results?
```
SLE
LYME DX
LEPROSY
INFECTIOUS MONONUCLEOSIS
MALARIA
HIV
HEPATITIS
PREGNANCY
RHEUMATIC FEVER
RHEUMATOID ARTHRITIS
```
107
Outline one dermatological condition in which DNA PROBES is useful?
WARTS (HPV)
108
```
Outline one condition in which the following miscellaneous investigations are utilized?
CHEST X-RAY
EOSINOPHILIA
ANA test
SEROLOGY
URINE DIP-STICK(glucose)
URINE CYTOLOGY(red cells)
```
```
CHEST X-RAY - HISTOPLASMOSIS and TB
EOSINOPHILIA - PARASITIC INFESTATIONS and FILARIASIS
ANA test - SLE
SEROLOGY - STREPTOCOCCAL CELLULTIS
URINE DIP-STICK(glucose) - DM
URINE CYTOLOGY(red cells) - VASCULITIS
```
109
Itemize 5 classes of treatment of dermatological conditions
```
Systemic treatments
Physical therapy
Other special procedures
Topical application
Surgery
```
110
Outline the 3 components of topical skin treatment
Powders
Grease and oil
Liquid
111
Combination of the 3 components of topical skin prep gives rise to what other 3 preps?
GREASY PASTES(powders + grease n oil)
LOTIONS, DRYING PASTES AND VARNISHES(powders + liquid)
COOLING PASTE AND CREAMS(powders +grease n oil + liquid)
112
Topical prep are a mixture of what 3 important constituents?
Bases
Preservatives
Active ingredients
113
Mention 2 types of Bases?
GREASY
| NON GREASY
114
When are greasy bases best used?
When an impervious covering is needed
| When the surface activity of an active ingredient is required
115
Itemize 6 categories of VEHICLES/BASES
```
PASTES
POWDER
PAINT
CREAM
OINTMEMTS
LOTIONS
```
116
What kind of vehicle are lotions?
Liquid vehicle - alcohol/aqeous based
117
What are lotions used for?
Used for inflamed, moist or infected skin
118
How do lotions mediate their function?
They reduce inflammation by EVAPORATION which in turn lowers the temp of the skin thereby promotes cooling and rapidly increases the concentration of the active drug
119
What products can lotions be found?
ANTIPRURITICS such as calamine lotion (zinc carbonate + ferric oxide)
120
What kind of vehicle is paints/tinctures?
ORGANIC SOLVENTS
121
How do paint/tinctures mediate their function?
They evaporate rapidly and deposit a film of the active ingredient on the skin
122
What products can paints/tinctures be found?
ANTISEPTICS/FUNGICIDES(usually contain aniline dyes)
| E.g Gentian violet, castellani's paint
123
What kind of vehicle are CREAMS?
Semi-solid viscous emulsions
124
What are the two types of creams?
WATER IN OIL(oily/cold cream)
| OIL IN WATER(varnishing cream)
125
Mention 3 examples of water in oil creams and under what conditions are they used?
Betnovate cream
Calamine cream
E45 cream
Useful for dry, irritating and icthyotic skin
(cools and leaves oil residue)
126
Mention 3 advantages of using creams
Miscibility with surface exudates
Ease of removal
Patient acceptability
127
What kind of vehicle are OINTMENTS?
Semi-solid grease or oily based
128
What important constituent do ointments usually contain?
Yellow or white soft paraffin
129
Ointments contain little water and preservative is usually required (T/F)
False
| Ointments contain NO water and preservative NOT usually required
130
How do OINTMENTS mediate their function?
They are occlusive and impede water loss from the skin
They have hydrating effects on the stratum corneum
Promote percutaneous absorption of medicinal agents
131
When are OINTMENTS used?
To soften and grease thickened dry skin
132
Itemize 3 examples of ointments?
Betnovate ointment
Sulphur ointment
Salicylic acid ointment
133
What kind of vehicle is PASTES?
Ointment base with a high proportion of powder
134
What important constituent do pastes contain?
Zinc oxide/starch and paraffin
135
What are the advantages of pastes over ointments?
It being thicker and drier than ointments;
1. absorbs secretions and exudations more readily
2. It's less macerating than ointments
136
What is the disadvantage of pastes compared to ointments?
They are LESS easy to remove than ointments
137
What is the contraindication to the use of pastes?
They should not be used on hair parts of the body
138
Which body sites are POWDERS best used and why?
INTERTRIGINOUS AREAS e.g axillae, intergluteal and interdigital clefts
These areas are moist due to perspiration and are prone to maceration and friction; powders being hygroscopic absorb the sweat reduce the frictional effect of the opposing surfaces
139
What kind of vehicle is GELS?
They are semi-plastic aqeous solutions
140
Itemize 3 advantages of using GELS?
They are cosmetically elegant
They are easy to apply and wash off
They are transparent, non-greasy, water miscible and varnish on rubbing
141
What is the advantage of gels over pastes?
They can be used on HAIRY body parts esp the scalp
142
What is the disadvantage of using gels?
They are easily removed by sweat
143
What are COLLOIDONS?
They are liquid preparations consising of pyroxylin(cellulose nitrate) in organic solvent
144
When are COLLOIDONS used?
They are used as protective to seal minor cuts and abrasion
145
Mention the disadvantage of COLLOIDONS?
They are often inflammable irritants to eye and mucous membrane and suitable for small area
146
Why are creams and lotions prone to spoilage?
Bcoz they contain water
147
Mention two examples of preservatives?
Parabens
| Chlorocresol
148
What is the drawback of preservatives?
They may occasionally cause contact dermatitis
149
What topical prep requires no preservatives? And why is this so?
OINTMENTS
| being anhydrous does not support the growth of bacteria and moulds
150
What are MOISTURIZERS?
Topically applied products that relieve the signs and symptoms of dry skin
151
Itemize the 3 classes of moisturizers?
Keratolytics
Occlusives
Humectants
152
What is the rationale for using MOISTURIZERS?
To increase the water holding capacity of the sub-cutis by external application of hygroscopic agents
153
Mention 5 examples of OCCLUSIVES? and state their mech of action?
```
Liquid paraffin
Lanolin
Coconut oil
Emulsifying wax
White soft paraffin
```
They provide a layer of oil on the skin surface and prevent evaporation of water
154
Mention 4 examples of HUMECTANTS? and state their mech of action?
Urea
Glycerin
Lactic acid
Glycolic acid
They penetrate the stratum corneum and increase it's capacity to retain water; hence useful in very dry skin
155
Mention 4 examples of KERATOLYTICS? and state their mech of action?
High conc of UREA
allantoin
Lactic acid
Glycolic acid
They break down keratin in cases of icthyosis and chronic eczema
156
Itemize 3 problems of topical therapy
Systemic absorption may occur if large areas of skin are treated topically
Contact allergy to topical prep is common
Folliculitis can occur bcoz of blockage of hair follicles
157
Itemize 5 indications for systemic treatment
```
Immunocompromise conditions
Extensive lesions
Recurrent cases
Resistant cases
Infections of nail and hair
```
158
Itemize 3 forms of physical therapy
Phototherapy
Radiotherapy
LASER
159
Itemize 5 conditions that can be treated with phototherapy?
```
Lichen planus
Psoriasis(pUVA)
Vitiligo
Alopecia areata
Acne
```
160
Itemize 5 surgical methods of treatment in dermatology?
```
Electrosurgery/surgical diathermy
Electrocautery
Cryosurgery
Electrodessication
Electrofulguration
Dermabrasion
Intralesional injection
```
161
List 5 indications for cryosurgery
```
Verruca vulgaris
Seborrhoeic warts
Molluscum contagiosum
Angiomas
Telangiectasia
```
162
Outline 3 indications for dermabrasion
Tattoos
Epidermal nevus
Adnexal tumours e.g syringoma
163
Mention 5 indications for Intralesional injection?
```
Psoriasis
DLE
Hypertrophic lichen planus
Lichen simplex chronicus
Keloids
```
164
What's the difference between electrodessication and electrofulguration?
electrodessication - electrode tip comes in contact with skin
electrofulguration - electrode tip does not contact the skin
