Eczema or Dermatitis

Pharmacotherapeutics of Eczema

1. Eczema Dr. V. S. Swathi Assistant Professor

2. Definition It is defined as an itchy erythematous eruption consisting of ill defined erythematous plaques or papules

3. Epidemiology In the world, atopic eczema affects 15-20% of children and 1-3% of adults worldwide In India, Prevalence of eczema is ranges from 0.44 -2.8%

4. Atopic Eczema It is common skin disorder in childhood Main reasons for this are: Genetic factors Environmental factors Immunological factors Characterised by: Chronic itchy skin Flexural involvement of skin creases Dry skin Presence of other atopic diseases Onset in first 2 years of life

5. Allergic contact dermatitis It is example for delayed Type IV hypersensitivity reactions Symptoms rarely develops on initial exposure to stimulus and manifests months/ years later following repeated exposures Allergens include: Metals- Nickel and cobalt Topical antibiotics – Neomycin Fragrance ingredients Rubber compounds Hair dyes Plant pollen Characterised by localised or generalised erythematous rash Common locations of Allergic contact dermatitis : Periorbital region Umbilicus Neck Hair line Hands

6. Irritant contact dermatitis   Most common form of occupational dermatitis It mostly affects hands Risk factors include : Builders Hair dressers Gardeners Health care workers Chefs Irritants include: Detergents Oil Water Inorganic acids Alcohol Plastics

7. Discoid Eczema Also known as Nummular dermatitis It is a form of chronic eczema Characterised by disseminated coin shaped eczematous lesion of the extremities It affects middle aged males

8. Statis Eczema Also known as Statis dermatitis or Gravitational dermatitis or Varicose Eczema It occurs in chronic venous insufficiency

9. Asteatotic Eczema Also known as Eczema craquele It affects lower legs Characterised by dry and cracked skin Risk factors include: Increase age Low humidity Frequent bathing

10. Risk factors Exposure to allergens Exposure to irritants Exposure to extreme temperatures Age Occupation Lack of moisturizing after bathing Co morbid conditions like: HIV infection Parkinson’s disease Chronic venous insuffiency

11. Etiology Allergens Irritants Household dust mites Molds Foods Chemicals Metals Water Extreme temperatures Abnormal functioning of person’s own immune system

12. Clinical Presentation Xerosis Pruritis Plaques Vesicles Spongiosis Oozing from ruptured vesicles Crusting at ruptured vesicles Lichenification Hyperkeratosis Cradle cap Cracked paving Localised or generalised erythematous rash Pink yellow greasy patches with bran like appearance Disseminated coin shaped lesion at lower extremities

13. Complications Erythema Excoriation Skin infections Sleep disorders Depression Erythroderma Eye problems Asthma exacerbations

14. Diagnosis Based upon history Based upon clinical presentation Patch test IgE levels

15. Non Pharmacological Treatment Avoidance of exposure to risk factors Use of emollients Phototherapy Bandaging Counselling

16. Treatment Algorithm

17. Drugs used in treatment of Eczema Drug Category Mode of action Dose Adverse effects Hydrocortisone Topical corticosteroid Decreases proliferation of epidermal cells 2.5-0.5% ointment twice daily Striae Telangiectasia Epidermal thinning Purpura Acne Ketoconazole Topical shampoo Decreases count of Pityosporum ovale on skin 2% shampoo twice for week for 6 weeks Irritation Hair loss Abnormal hair texture Dry skin Scalp pustules Prednisolone Oral corticosteroid Controls rate of T -Cell proliferation 20mg/day for 7 days Acne Diabetes Hypertension Osteoporosis Delayed wound healing

18. Cetrizine Antihistamine Sedation 5-10mg-PO-at night Somnolence Head ache Fatigue Dry mouth Malaise Tacrolimus Calcineurin Inhibitor Decreases T-lymphocyte proliferation 0.03-0.5% ointment Burning sensation Flu like symptoms Skin Erythema Head ache Application site oedema Ciclosporin Systemic immune suppressant Block activation of T lymphocytes 2.5 to 5 mg/kg/day Tremor Nephrotoxicity Hypertension Infection Hirsutism Azathioprine Systemic immune suppressant Block activation of T lymphocytes 2mg/kg/day Leukopenia Infection Lymphoma Alopecia Arthralgia

19. Methotrexate Systemic immune suppressant Inhibit proliferation of T cells and B cells 10-25mg once per week Reddening of skin Hyperurecemia Glossitis Stomatitis Gingivitis Mycophenolate Mofetil Systemic immune suppressant Inhibit proliferation of T cells and B cells 500mg-BD-PO Hyperglycaemia Hypercholesterolemia Hypomagnesaemia Dyspnoea Leukopenia Phototherapy Narrow band UVB Calms inflammation 2/3 times per week Burning of skin Premature ageing of skin Increase risk of skin cancer Photosensitivity Cataract

20. Resources https ://doi.org/10.1016/j.abd.2018.10.004 https://doi.org/10.1016/j.jaad.2019.09.073 https://sci-hub.tw/https://doi.org/10.1111/bjd.16717 https://www.bmj.com/content/bmj/361/bmj.k1332.full.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6790711/pdf/BJD-181-707.pdf