Target organ toxicity - Derma damage Flashcards
What is the function of the epidermis?
Protection against:
- Water loss
- Penetration of chemicals
- Infections of microorganisms
What is the definition of Contact dermatitis and which subgroups does it include?
Contact dermatitis is defined as changes in the skin resulting from contact or exposure to an exogenous chemical or physical agent.
Subclasses of contact-induced skin reactions include:
- Phototoxicity
- Alterations in pigmentation
- Irritant contact dermatitis (ICD)
- Allergic contact dermatitis (ACD)
How is irritant contact dermatitis (ICD) described?
Localized inflammation that produces direct cellular injury upon dermal penetration by the irritant agent.
Characterized by “nonsensitization”, the intensity of the inflammatory response is proportional to the exposure dose.
How is acute contact dermatitis (ACD) described?
Easy to identify due to potent irritants
How is chronic / cumulative irritant dermatitis described?
Reaction that appears up to years of exposure due to weak irritants
Is often misdiagnosed as allergic dermatitis
Which mechanism of stimulation of the immune systems are there?
Types of immune responses:
- Type 1 (A) – allergy, atopy, anaphylaxis
- Type 2 (B) – antibody
- Type 3 (C) – immune complex
- Type 4 (D) – delayed response
What does nickel dermatitis depend on?
Severity depends on:
1) area of contact, 2) occlusion, 3) duration, 4) frequency
Which immune response is induced in urticaria (nældefeber) and what drugs causes it?
Type 1 (IgE mediated uricaria)
Mechanism - type 1 allergic reaction (A)
Penicillins and cephalosporin
Which immune response is induced in angiodema?
Type 1) IgE mediated or due to drugs or protein defect
Deep subcutaneous and or mucosal swelling
Which drugs commonly induce skin reaction?
Penicillins, Sulphonamides, Phenytoin, Carbamazepine, Gold, Gentamicin
Which cells are involved in leucocyte-associated type 4 reactions and which type of skin reactions does it induce?
Cells involved:
- 4a: Th1 cells;
- 4b: Th2 cells;
- 4c: Cytotoxic cells;
- 4d: T cells
All with the liberation of corresponding immune mediators eg. interleukins
Give rise to:
- TEN (toxic epidermal necrolysis). TEN: confluent bullous lesions.
- Stevens Johnson syndrome –> blistering and skin loss
Which drugs can induce the derma reaction TEN?
Sulfonamides, antimicrobials, allopriunol, aromatic amine anticonvulsants, anti-retrovirals and NSAIDs
Which drugs can induce the derma reaction TEN?
Sulfonamides, antimicrobials, allopriunol, aromatic amine anticonvulsants, anti-retrovirals and NSAIDs
