Dermatology Revision

Introduction
 The epidermis is a stratified squamous epithelium consisting primarily of cells called

keratinocytes in progressive stages of differentiation from deeper to more superficial
layers (from below to upward)
 The named layers of the epidermis include 4 layers: stratum basalis (basal cell layer),
stratum spinosum, stratum granulosum (granular cell layer, and stratum corneum
(horny cell layer).
 stratum corneum are the largest and most abundant of the epidermis it is devoid of
nuclei and is the primary protective barrier .
 The epidermis contains no blood vessels and is entirely dependent on the underlying
dermis by diffusion through dermoepidermal junction (DEJ)
 Dermoepidermal junction consists of 2 layers, the lamina lucida and lamina densa.
 The mucous membrane of the mouth differs from the skin by absence of both granular
and horny layers with the exception of the dorsum of the tongue and the hard palate.
 Electron microscopy of the epithelial cells of the oral mucosa show only few well-
developed desmosomes.
 The biologic week point of oral mucosa is epithelial attatchment.
 The oral epithelium tolerates a continuously moist surface; mechanical, chemical, and
thermal stress.
 The base-line rate of epithelial renewal in the human oral epithelium is about 5 days. This
high basal turnover is for protection.
 Heavy microbial colonization in the oral cavity  Factors that predispose to wound
infection:
 The presence of avascular tissue

 Foreign material,
 Large inocula of new pathogens,
 Deficiencies in the ability of the host to respond
Behcet’s disease
 Multisystem disease
 CNS involvement is associated with high mortality rate
 Mostly due to immunological factor
 Can be diagnosed by Pathergy test
 Characterized by remissions and exacerbations

 Dapsone: can be effective in treatment.
 Tetracycline mouth wash: is the drug of choice for oral ulcers.
Diagnostic criteria
Major features
Recurrent aphthous (oral ulcers).
Genital ulcers.
Eye lesions:
Minor features
Arthritis without deformity and ankylosis
Gastrointestinal lesions characterized by ileocecal ulcers
Epididymitis
Vascular lesions
Central nervous system symptoms
The most common sites are the tongue, lips, buccal mucosa, and gingiva. Meanwhile, the
tonsils, palate, and
pharynx are less common sites for oral ulcers
Oral ulcers can be classified into 3 types.
 Minor ulcer: This consists of 1-5 small,
moderately painful ulcers persisting for 4-14 days
 Major ulcer: This is 1-10 very painful ulcers, measuring 10-30 mm, persisting up to 6 weeks,
and possibly leaving a scar upon healing
 Herpetiform ulcer: This is a recurrent crop of as many as 1000 small and painful ulcers
Erythema Multiform (EM)
 Affects skin and mucosa (70% have mucosal involvement)
 Characterized by target lesions in the skin
 Classified into EM minor and EM major
 The lesions begin on the acral areas in EM major
 Mucosal involvement is more severe in EM major
 Hemorrhagic crusting of the lips and ulceration of the non keratinized mucosa is seen in
EM major
 It can affect the eye
 Herpes simplex virus (HSV) is the most common inducing cause but EM can be also
induced by drugs
Oral Leukoplakia
 It is non infectious disease
 Have higher risk for cancer (premalignant)
 White lesions can't be removed by a gauze swab
 Some leukoplakias are white and warty (verrucous leukoplakia). Others are mixed white
and red lesions (erythroleukoplakias )
 Suspected causes are tobaceo, trauma, infection, chemicals, alcohols, immune defects
 Can be treated by laser excision or medically by retinoids
Pemphigus valgaris
 Autoimmune, intraepidermal blistering disease affecting skin and mucous membranes.
 Circulating IgG autoantibodies bind to Desmogleins causing suprabasal acantholysis of

epidermal cell
 The oral mucosal lesions in 50%-70% of cases appear 6- 12 months before the skin
lesions
 More than 90% of patients will develop oral lesions at some time during the course of the
disease
 It causes flaccid bullae in the skin and erosions and ulcers in the mucous membrane
 Diagnosis by biopsy, Tzank smear, direct and indirect immunoflourescence
 Treated by systemic steroid
 Mortality rate is 5% and it is mainly due to Steroid-induced complications and Sepsis.
 Dermoepidermal junction is the target in pemphigus vulgaris
Oral candidiasis
 Candida Albicans is the main causative organism
 The organism present in 3 forms; yeast cell, hyphae and mycelium (pathogenic phase).
 Oral candidiasis types: oral thrush, chroinc hypertrophic candidiasis (candidal

leukoplakia which is premalignant), chronic atrophic candidiasis (mucosa is
erythematous with well demarcated border), glossitis, and black hairy type.
 Diagnosed by: Scrape and 10% KOH smear, Fungal culture and Serum tube test
 Treated by Nystatin topically and Fluconazole systematically
Cutaneous manifestations pf HIV
 Human immunodiffency is a retrovirus
 HIV is transmitted through body fluids that include: Blood, Semen, Vaginal and rectal
fluids, Breast milk and Transplacental.
 The virus may infect children by transplacental transmission or by breastfeeding and

rarely by sexual abuse by adults with HIV-1 have also been reported.
 Langerhans cells are the first cellular targets of the virus
 HIV targets to kill CD4 T helper cells causing CD4 T cells depletion.
 Plasma viremia appears 4-11 days after mucosal entrance of the virus.
 Kaposi sarcoma (KS) incidence increases in HIV
 Lab. Diagnosis includes: Enzyme-linked immunosorbent assay (ELISA), Western blot or

immunofluorescent assay, The ratio of CD4+ to CD8+ T cells ,Polymerase chain reaction
(PCR) and viral culturing
 Treated by Antiretroviral drugs (ARD): Protease inhibitors, Integrase inhibitors,

Nucleoside/ nucleotide reverse transcriptase inhibitors (NRTIs), Non- nucleoside reverse
transcriptase inhibitors (NNRTIs), Chemokine co-receptor antagonists
Oral lichen planus
Oral lichen planus (OLP) is an autoimmune non infectious disease characterized by bilateral
white grey streaks (Wickham striae)
Oral squamous cell carcinoma (SCC) developed in fewer than 5% of patients with OLP
Up to 44% of patients with OLP develop coincident skin lesions.
More than 70% of patients with cutaneous lichen planus develop coincident OLP.
Oral lichen planus can be erosive
Oral candidiasis is the differential diagnosis of oral lichen planus
syphilis
Causative organism: A spirochaete known as Treponema pallidum (T.P.).

Mode of transmission: Mainly by direct contact with infectious lesions.
1. Sexual contact is the most common method o infection.
2. Accidental contact e.g. medical personnel.
3. Needle pricks and blood transfusion.
4. Transplacental infection from infected mother to her baby.
5. Indirect contact e.g. from WC is rare
Classification:
A) Acquired syphilis.
It is further subdivided into 4 stages: 1)Primary syphilis.
2)Secondary syphilis.
3)Latent syphilis.
4)Tertiary syphilis.
B) Congenital syphilis.
Primary (1ry) syphilis
Its primary lesion is called chancre (90% genital and 10% extragenital). spontaneous healing
within 2-4 weeks leaving a thin scar.
75% of patients enter phase of latency (latent syphilis) i.e. complete freedom clinically in the
presence of +ve serological tests. It lasts from 2 weeks to 6 months.
25% of patients develop manifestations of secondary syphilis while the chancre is still present.
Secondary (2ry) syphilis
The lesions appear 1-6 months after the appearance of the primary lesion.
Mucous membrane lesions “Mucous patches”: appear as shallow white erosions on mucosal
surfaces
After sometime, the mucous patches show confluence giving “Snail-track ulcers”.
Tertiary (3ry) Syphilis include:
1- Benign late syphilis: Gumma.
2- Cardiovascular syphilis.
3- Neurosyphilis.
Mucosal lesions of 3ry syphilis are: Gumma, deep interstitial glossitis causing “macroglossia” ,
ulcer with punched out edge and Leukoplakia
Stigmata of congenital syphilis :
1) Dental changes.
Hutchinson’s teeth Moon’s molar
2) Other stigmata.
Interstitialkeratitis
Perforation of the hard palate
Saddle nose.
8th nerve deafness
Rhagades: Linear lesions around the mouth and anus.
Sabre tibia.
Penicillin is the drug of choice in treatment of syphilis.

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Introduction

 The epidermis is a stratified squamous epithelium consisting primarily of cells called

 The presence of avascular tissue

 CNS involvement is associated with high mortality rate

 Mostly due to immunological factor

 Can be diagnosed by Pathergy test

 Characterized by remissions and exacerbations

 Tetracycline mouth wash: is the drug of choice for oral ulcers.

 Affects skin and mucosa (70% have mucosal involvement)

 Characterized by target lesions in the skin

 Classified into EM minor and EM major

 The lesions begin on the acral areas in EM major

 Mucosal involvement is more severe in EM major

 It can affect the eye

 It is non infectious disease

 Have higher risk for cancer (premalignant)

 White lesions can't be removed by a gauze swab

 Can be treated by laser excision or medically by retinoids

 Autoimmune, intraepidermal blistering disease affecting skin and mucous membranes.

 Circulating IgG autoantibodies bind to Desmogleins causing suprabasal acantholysis of

 Diagnosis by biopsy, Tzank smear, direct and indirect immunoflourescence

 Treated by systemic steroid

 Mortality rate is 5% and it is mainly due to Steroid-induced complications and Sepsis.

 Dermoepidermal junction is the target in pemphigus vulgaris

 Candida Albicans is the main causative organism

 Oral candidiasis types: oral thrush, chroinc hypertrophic candidiasis (candidal

 Treated by Nystatin topically and Fluconazole systematically

Cutaneous manifestations pf HIV

 Human immunodiffency is a retrovirus

 The virus may infect children by transplacental transmission or by breastfeeding and

 Langerhans cells are the first cellular targets of the virus

 Kaposi sarcoma (KS) incidence increases in HIV

 Lab. Diagnosis includes: Enzyme-linked immunosorbent assay (ELISA), Western blot or

 Treated by Antiretroviral drugs (ARD): Protease inhibitors, Integrase inhibitors,

Oral lichen planus

Causative organism: A spirochaete known as Treponema pallidum (T.P.).

Penicillin is the drug of choice in treatment of syphilis.

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