Atopic Dermatitis

Question 1

Atopy

Answer 1

• group of disorders including asthma/hayfever which occurs in families.
• early childhood exposure to Allergens/ Maternal Smoking –> stimulation of IgE production

Question 2

Pathomech

Answer 2

• unknown
• but selective activation of Th2 CD4 in the skin –> drives inflmm
• increase in Serum IgE

Question 3

Influence of Atopy

Answer 3

• familial disease + maternal influence:
• 20-30% if one parent
• 50% if both parents affected

-lack of infection in Infancy –> lead to dev of Atopic Dermatitis/Asthma

Question 4

genetic studies

Answer 4

abnormality in:

• -> b-subunit of IgE-R
• -> Th2 cytokines gene

Question 5

what exacerbates Atopic Dermatitis

Answer 5

• systemic/skin infection
• anxiety/stress
• dairy products/animal hair

Question 6

Common Clinical Features

Answer 6

1) Itchy Erthythematous Scaly Patches (elbows/ankles/knees/neck)
2) acute lesions may weep/exudate (show small vesicles)
3) Scratching –> excoriations + Repeated Rubbing = Lichenification
4) Post inflmm Hyper/Hypo Pigmentation (slowly fades)
5) Follicular Hyperkeratosis (rough skin)

Question 7

Complication of Atopic Dermatitis

Answer 7

1) Secondary Infxn (Staph.A)
2) Cutaneous Viral Infection (scratching –> Viral warts/mollecum)

2) Eczema Herpeticum (Kaposi Varicelliform Eruption)
- herpes simplex infection
- widespread
- small blisters + punched out crusted lesions
- fever + malaise

Question 8

Treatment Overview

Answer 8

-Topical tx are sufficient

-TRIPLE TX:
> TOPICAL STEROIDS
> Oily Creams / Bath Oils (soap substitutes)

-Education (avoid irritants)

Question 9

Treatment of Atopic

Answer 9

1) STEROIDS:
- mild steroid (1-2.5% Hydrocortisone) - Face/Young kids
- mod steroid (aclomethasone) - Adult body surface
- potent steroid (Betamethasone) - Areas with Thick Skin Surf

2) TOPICAL IMMUNOMODULATORS
- Tacrolimus Ointment
- Pimecrolimus (skin gel inflmm cyt inhib)
* doesn’t cause skin atrophy –> eyelids/face (sensitive area)

3) ABX:
- bacterial superinfection
- penicillin v - strep/ Flucloxacilin - Staph

4) Sedating Antihistamines:
- Hydroxyzine

5) Bandaging
- helpful for Absorption of treatment + stop ptnt from Scratching
- Paste Bandaging -> resist/lichenified Eczema

6) Second Line agents:
- UV photography –> supress cut infilration
- PREDNISOLONE
- Cyclosporin (inhibit Il-2 prod)
- AZATHIOPRINE –> inhibit Purine synthesis