1. HOW TO DEAL WITH A DERMATOLOGICAL CASE.
By: Dr. Ashraf Hamza (Professor of Dermatology)
FUNCTION OF SKIN
(1) Protection (2) Temperature regulation (3) Sensation (4) Excretion (5) Synthesis of vitamin D
(6) UVR screening (7) Regulation of blood pressure (8) Absorption (9) Psychogenic function
For management of dermatological disease, certain items must be fulfilled;
1) Hx taking (2) Clinical examination (3) Investigation -if needed (4) Treatment
(A) HISTORY
1 – Personal History: a) Name: for patient identification.
b) Age & sex: certain diseases occur in certain age and sex.
c) Occupation: skin exposed to external environment (house wives).
d) Residence: endemic disorder such as leprosy and leishmaniasis.
2 – Present History: a) Complaint: may be disfigurement, itching or burning sensation.
b) Onset: acute, chronic or acute exacerbation on top of chronic illness.
c) Course: progressive, stationary or regressive.
3 – Past History: Important in recurrent disorders.
4 – Family History: Important in congenital and infestation disorders.
5 – Drug history: Drugs taken before appearance of disease.
(B) CLINICAL EXAMINATION
1 – General examination
Skin disorders associated with systemic disorders.
2 – Local examination
a) Examination of skin:
- examination from distance - distribution
- close-up examination - border
b) Examination od skin appendages: mucus membrane, nails and hairs.
EXAMINATION OF THE SKIN
(A) From distance: Shows the distribution of lesions that may be:
1) Discrete distribution:
Multiple lesions separated by
normal skin.
2) Unilateral distribution:
Lesions involving only one
side of the body.
3) Generalized distribution:
Lesions involving more than
50% of body surface area.
4) Grouped
distribution: Lesions
are restricted to a
localized area.
5) Linear distribution: Lesions
are arranged along a line. It
may be Kobner’s
phenomenon which is
appearance of isomorphic
lesions along the site of blunt
trauma.
6) Zosteriform distribution:
Lesions are restricted to
dermatome.
7) Follicular distribution:
Lesions are arranged along hair
follicles.

2. (B) Close-up examination: Shows the border of lesions that may be:
1) Well-defined border: Marked
separation between the edge of the
lesion and normal skin.
2) Ill-defined border: Difficult to
identify the separation line between
the lesion and normal skin.
3) Circinate border: The lesion
increases in size by peripheral
extension and healing at the centre.
TYPES OF SKIN LESIONS
Skin lesions may be: initial lesions, secondary lesions or specific lesions.
(A) INITIAL LESIONS
1) Macule: Discoloration of skin <1cm diameter. Patch: if >1cm.
2) Papule: Solid elevation of the skin <1cm diameter. Plaque: if >1cm
(a) Dome shaped: papule with a smooth convex surface.
(b) Flat topped: papule with a flat surface. It is describe as lichenoid papule.
(c) Umbilicated: dome shaped papule with central notch.
(d) Verrucous: papule with fine mammilated surface.
3) Nodule: Elevated solid skin lesion with dermal extension.
4) Vesicle: Fluid-containing lesion <1cm diameter. Bulla: if >1cm
(a) Intraepidermal separation: flaccid bulla
(b) Subepidermal separation: Tense bulla
(B) SECONDARY LESIONS
1) Pustule: Elevated lesion containing pus.
2) Scales: Dry surface dt abnormal keratinization.
(a) Fine branny: Pytriasis versicolor
(b) Greasy: Seborrheic dermatitis
(c) Lamellar: Psoriasis
(d) Fish scales: Ichthyosis
(e) Collarette: Pityriasis rosea
(f) Horny (keratotic): Discoid LE
3) Crust: Dried exudates, either pus or blood.
4) Erosion: Superficial epidermal loss.
5) Ulcer: Deep dermal loss, thus it has characteristic edge.
6) Fissure: Longitudinal discontinuity off the skin.
7) Atrophy: Thinning of skin dt thinning of epidermis or dermis or both.
8) Scar: Replacement of the skin by FT
9) Lichenification: Descriptive term of 3 criteria:
(a) Thickening of skin. (b) Hyperpigmentation. (c) Increased skin markings.
(C) SPECIFIC INITIAL LESIONS
1) Wheal: Specific to urticaria. It is edematous erythematous lesion which is migratory.
2) Scutulum: Specific for favus. It is concavo-convex golden yellow cup stuck to scalp.

3. 3) Comedone: Specific to acne. Either: - Black head: papule with central black spot.
- White head: small pale papule.
4) Tunnel (burrow): Specific for scabies. It is a curved line dt burrowing of female mite to skin.
5) Target lesion: Specific to erythema multiforme. Consist of 3 zones:
(a) Central zone: cyanotic. (b) Intermediate zone: pale (c) Outer zone: erythematous
6) Herald patch: specific for P.rosea. It has 3 concentric zones:
(a) Central cafe au lait. (b) Intermediate collaretic scales. (c) Peripheral erythematous.
EXAMINATION OF SKIN APPENDAGES
(A) Examination of mucus membranes:
Check for any erosion, ulceration, plaque, pigmentation, white streaks.
(B) Examination of nails:
Nail pitting: in cases of ................
Nail discoloration: ........................
Nail fold swelling: ........................
Nail dystrophy: ..............................
(C) Examination of hair.
1) Hair loss: either
Diffuse hair loss.
Patchy or alopecia  Cicatrical or non cicatrical (Differentiate by ........................)
2) Hair growth in abnormal sites. (In woman: hirsutism)
INVESTIGATION
There are certain investigations specific to the skin that can help in the dx of some skin diseases.
1) Wood’s light: It is a special UV light which if thrown to:
Normal skin – reflects deep violet colour.
Pityriasis versicolor – reflects golden yellow colour.
Erythrasma – reflects deep red colour
Tinea capitis – reflects brilliant green colour
2) Skin scraping: Used for dx of fungal infection of skin.
Procedure:
Skin is scratched by scalpel. The resulted scales are places on glass slide, then 10% KOH is added and examined under
microscope. (eg: hyphae of dermatophytes)
Hair sample: endothrix
ectothrix
3) Patch testing: Used for dx of contact dermatitis.
Procedure: aluminium strip with multiple holes is fixed on the back. The antigens are placed each in one hole. Then,
another aluminium strip is placed over the previous one and left for 48 hours. On removal of the strip, we examine the
sites o different allergenfor erythema and vesicles. If present, the test is positive.
4) Immunoflourescent tests: Used for dx of autoimmune disorders. Either:
Direct test – Detect antibody in the skin. Skin biopsy is taken and flourescent anti-antibody is placed on it.
Indirect test – Detect antibody in serum of patient. Flourescent anti-antibody is added to the patient serum.
5) Skin biopsy and histopathology:
Demonstrate the pathological
changes in the diseased area.
Usually diagnostic.
Histology of skin (epidermal layer):
1) Horny layer (stratum cornium)
2) Granular cell layer
(stratum granulosum)
3) Prickle cell layer
(stratum spinosum)

4. 4) Basal cell layer
(stratum basale)
Pathological terms:
1) Hyperkeratosis: increased thickness of horny layer (stratum cornium).
2) Parakeratosis: retention of nuclei in horny layer (stratum cornium).
3) Hypergranulosis: increased thickness of granular cell layer (stratum granulosum).
4) Acanthosis: increased thickness of prickle cell layer. Either uniform or saw tooth acanthosis.
5) Spongiosis: edema of prickle cell layer (stratum spinosum).
6) Acantholysis: Loss of coherence between cells of prickle cell layer (stratum spinosum)/
Hyperkeratosis Parakeratosis Acanthosis
Spongiosis Acantholysis
THERAPY IN DERMATOLOGY
Principles of topical therapy:
1) Type of skin lesion: Wet lesions need creams, dry lesions need ointments.
2) Never do any harm: don’t use irritant and sensitizers.
3) Never overtreat: This usually occurs when a patient ask a friend and use many medications.
4) Instruct the patient adequately: It is not important to tell a patient how to swallow a pill but it is essential to tell
patients how to apply local medications.
5) Prescribe the correct amount of medication for the area and dermatoses to be treated.
6) Change the therapy as the response indicates.
7) If the prescription is expensive, explain this fact to the patient.
8) Therapy plus is usually indicated, advise the patient to continue to apply the medications for a specific period after
the dermatoses apparently cleared. This is to prevent recurrence.
9) Ask the patient to cantact you if there is any question or if the medicine appeared to irritate the dermatoses.
EFFECTS OF LOCALLY APPLIED DRUGS

5. 1) Antipruritic Agents: Relieving itching in various ways. Eg: Calamine lotion.
2) Keratoplastic Agents: Increased the thickness of horny layer. Eg: Tar
3) Keratolytic Agents: Remove or soften horny layer. Eg: Salicylic acid 4%-6%, urea 20%-40%, lactic acid 20%
4) Antieczematous: Stop the secretions by various actions. Eg: Corticosteroids.
5) Antiparasitic Agents: Destroy or inhibit living infestations. Eg: Permethrim 5%
6) Antiseptics: Destroy or inhibit bacteria, viruses or fungi.
7) Antibacterial topical medications: destroy or inhibit bacteria. Eg: Gentamycin, fusidic acid, erythromycin,
tetracycline, neomycin, and chloramphenicol.
8) Antiviral topical agents: destroy or inhibit viruses. Eg: Acyclovir.
9) Emollient Agents: Soften skin surface. Eg: Cold cream and Vaseline.
TYPES OF TOPICAL MEDICATIONS
1) Compresses: Remove the crust. Eg: Potassium permanganate 1/8000 and saline.
2) Drying agents: Dry oozing skin. Eg: Gentian violet 1% and microchrome 1%
3) Creams: They are semisolid emulsion systems containing both water and oil. They are water miscible, cooling and
soothing, and are well absorbed into the skin.
Used in acute oozing skin disorders.
4) Ointments: They have oil or grease. They are semisolid and anhydrous substances.
Used in chronic, dry skin disorders. Eg: Vaseline petroleum jelly
5) Gels: They are semisolid preparations gelled with high molecular weight polymers, such as methylcellulose.
Non-greasy, water miscible, easy to apply and wash off. Especially suitable for treating hairy parts of body.
6) Paints: Liquid preparations, either aqueous, or alcoholic (tinctures), which are usually applied with a brush to the
skin. They are evaporate, and are therefore cooling as well astringent and antiseptic. They may also be used as
protectives to seal abrasions.
7) Lotions: Combination of powder and water. Able to cover wide surface area of skin dt increased evaporating surface.
Not suitable for xerosis pruritus. Eg: Calamine lotion.
QUANTITY OF CREAMS TO PRESCRIBE
FACTOR AFFECTING THE QUANTITY
1) Types of dermatoses: acute or chronic.
2) Base of topical medication: Ointments spread over skin more than creams.
3) Intelligence of patients: educated patients usually consume smaller amounts.
HOW TO ASSESS THE QUANTITY OF TOPICAL MEDICATIONS?
1) Use the fingertip unit to assess the quantity of cream needed to cover a certain body surface area.
2) One fingertip unit is approximately 500mg.
Amount needed Duration of application Frequency of application Surface area
15gm 14 days b.i.d Hand
30gm 14 days b.i.d Arm
60gm 14 days b.i.d Leg
480-960gm 14 days b.i.d Entire body