Irritant contact dermatitis by dr maria saeed

A lilttle effort for all those Residents who wants to study from ROOK'S textbook of dermatology and also wants to save time

1. IRRITANT CONTACT DERMATITIS By Dr.Maria Saeed

2. What is irritant contact dermatitis? Irritant   contact dermatitis  is a form of skin  inflammation  caused by contact with substances and/or environmental factors that injure the skin, damaging the skin barrier.

3. Introduction and general description Reversible cellular injury may cause contact urticaria or dermatitis dependent on the nature of the insult. Where there is no apparent cellular injury, various sensory symptoms such as stinging, smarting and burning may occur. The following types of irritant contact reaction may be distinguished: Burns. Irritant contact dermatitis: • Acute ( toxic ) irritant contact dermatitis . • Cumulative irritant/insult contact dermatitis. Transient or immediate ‐type, non‐immune , contact urticaria . Symptomatic (subjective) irritant responses. Other: pigmentary and granulomatous responses and those localized to appendageal structures

4. Who gets irritant contact dermatitis? Irritant contact   dermatitis  will affect anyone with sufficient exposure to  irritants with  atopic dermatitis   are particularly  susceptible . Occupational   hand dermatitis  is due to irritants in 80% of cases in   cleaners ,  hairdressers , food handlers ,and   healthcare personnel . Irritant contact dermatitis can affect all age groups, both sexes, and any race.

5. What causes irritant contact dermatitis ? Irritant contact dermatitis develops when chemical or physical agents damage the skin surface faster than the skin can repair. Irritants remove oils and natural moisturising factor from the outer layer of the skin, allowing chemical irritants to penetrate the  skin barrier  and trigger inflammation. common skin irritants   1) water ,  soaps , and, in the era of COVID-19,  hand sanitisers .   2) Occupational irritants can include wet work, detergents, solvents, acids, alkalis, adhesives, and metalworking fluids 3)  Topical medications such as  retinoids  and benzoyl peroxide.   4) Friction , sweating, and heat are examples of environmental factors

6. Pathophysiology Skin barrier dysfunction is a key reason for irritation. skin provides the first and most important line of defence many substances penetrate readily into and through the epidermis principal epidermal barrier resides almost entirely in the stratum corneum Damage to the stratum corneum is normally followed by an increase in percutaneous absorption and in transepidermal water loss (TEWL) lipids are arranged as stacked membrane sheets in the intercellular space and are produced from lamellar granules in the cells of the granular cell layer of the epidermis tight junctions between epidermal cells have also been shown to provide a block to water loss filaggrin mutations may predispose to irritant contact dermatitis

7. Mechanism of action of irritants Detergents : Destruction of lysosomal enzymes in horny layer causing dryness and scaling signs of chronic inflammation increased DNA synthesis, acanthosis and changes in cellular metabolism irritants such as croton oil and phenolesters are chemotactic : for polymorphonuclear leukocytes at non‐toxic concentrations may cause pustular reactions. Organic solvents such as methanol or chloroform: will damage blood vessels, causing hyperaemia . dimethyl sulfoxide (DMSO): effective degranulator of mast cells

8. barrier disruption has been shown to induce : release of interleukin 1α (IL‐1α) upregulation of tumour necrosis factor α (TNF‐α) and granulocyte–macrophage colony‐stimulating factor (GM‐CSF). rise in Langerhans cell‐derived IL‐1α stimulated by GM‐CSF and IL‐1α production. the loss of the normal extracellular calcium gradient stimulates lamellar body secretion and barrier repair Oxidative stress also contributes to the development of inflammation with various

9. Histopathologic changes spongiosis Perivascular infiltrates Hyperkeratosis acanthosis

10. Clinical features of irritant contact dermatitis Resembles dermatitis of any cause Usually is confined to the site of contact with the irritant stinging , smarting, burning sensations of dryness and tightness, through delayed stinging. Irritants may also penetrate skin via appendageal structures and cause folliculitis . Burning and pain more common symptoms than itch Acute dermatitis due to a single severe exposure Chronic dermatitis due to mild irritants or repetitive cumulative exposure

11. Comparison between changes in acute and chronic dermatitis Acute CD Localised  well-defined, redness, papules, swelling, blistering (vesicles/ bullae ) Example: kneeling in wet cement, which is very alkaline, causing severe dermatitis of the knees Chronic CD Initial dryness and cracking of the skin Evolves to include inflammatory  changes with redness and itch May develop tolerance or hardening with time Examples include dribble rash,  napkin dermatitis ,  housewife’s eczema , ring dermatitis

12. Irritant contact dermatitis

13. Mechanical irritation involving digits House wife type eczema

14. Classification of severity no objective ways of classify severity Non‐specific assessment: Dermatology Life Quality Index ( DLQI) or quantify the irritant response by measuring: Erythema Transepidermal water loss Hydration Skin tightness

15. Interdigital dermatitis, also called the ‘ sentinel sign ’, is regarded as an early stage of irritant contact dermatitis affecting the hands. It is commonly seen in occupations involving wet work. Interdigital dermatitis

16. complications of irritant contact dermatitis Disseminated secondary eczema Lichenification Secondary bacterial infections

17. Diagnosis D etailed medical history including occupational exposures clinical examination. There is no test for irritant contact dermatitis .   Patch  testing  may be necessary to distinguish it from  allergic contact dermatitis . Irritant and allergic contact dermatitis can co-exist.

18. D ifferential diagnosis   Allergic contact dermatitis — which may co-exist Other causes of hand dermatitis such as  atopic hand dermatitis Psoriasis

19. T reatment General measures : Avoidance of all potential irritants Emollients Barrier  creams Specific measures : Specific treatments for some chemical irritants eg , calcium gluconate  gel for hydrogen fluoride burn Topical medications —  topical steroids ,  calcineurin  inhibitors ,  crisaborole Phototherapy .

20. THANK YOU