12. Common Inflammatory Skin Diseases Flashcards
What are the pathophysiology and types of eczema?
Path = primary genetic defect in skin barrier function (loss of function of filaggrin)
TYPES
1) Atopic dermatitis (ENDOGENOUS)
- allergic disease - itchy rash is particularly noticeable on head and scalp, neck, inside of elbows, behind knees, and buttocks
- Filaggrin def
2) Contact dermatitis (EXOGENOUS)
- Allergic - hypersensitivity reaction in the skin
- Irritant contact dermatitis - direct reaction
3) Seborrhoeic dermatitis - dry or greasy peeling of the scalp, eyebrows, and face, and sometimes trunk
- Newborn = thick, yellow, crusty scalp rash called cradle cap
4) Dyshidrosis = palms, soles, sides of fingers/toes (worse in warm weather)
5) Discoid = round spots of oozing or dry rash, with clear boundaries, often on lower legs (worse in winter)
List the signs and symptoms of eczema
Small lesions (entire body) = PAPULES + VESICLES on erythematous base
More common on face and extensor surfaces in infants and flexor surfaces in children/adults
Itchiness - can lead to excoriations + lichenification
Nail pitting, ridges
Blisters
Thickened skin
Weepy (exudative), crust
Scaring, colour change
What investigations should be performed if eczema is suspected?
Clinical Dx
Skin biopsy
Patch testing (allergic contact dermatitis)
Skin swab - if infection suspected
How is eczema correctly managed?
Lifestyle = avoid allergen/irritant, bathing once or more daily in warm water, avoid soap
TOPICAL
1) Emollients = oil based (zerobase)
2) S/S = any emollient, dermal 500 lotion/eczmol cream (chlorhexidine)
3) Steroids (fingertip units OD 1-2w for flare, soles/palms require potent) = hydrocortisone 1% (mild), eumovate (mod), betnovate (potent), dermovate (v. potent)
4) Immunosuppressants = pimecrolimus and tacrolimus (require regular blood test monitoring)
ORAL
1) Sedating antihistamine - reduce nighttime scratching
2) Abx (sec infection)
3) Antivirals (sec herpes, molluscum, warts, e herpeticum)
Phototherapy + immune suppression (methotrexate + folate: monitor FBC, U+E, LFTs every 2-3m) = severe non-responsive
Outline the pathophysiology of acne
Hair (pilosebaceous) follicles are clogged with dead skin cells and oil from the skin
Androgens (puberty, polycystic ovary syndrome, congenital adrenal hyperplasia) increase production of sebum
Excessive growth of Propionibacterium acnes (normally present on the skin)
What are the signs and symptoms of acne?
Primarily affecting - face, upper chest, back
Blackheads
Whiteheads
Pimples
Oily skin
Scaring
Secondary - anxiety, reduced self-esteem, depression
Post-inflammatory hyperpigmentation (PIH)
How is acne best managed?
Lifestyle = eating less carb
Comedonal acne =
1) Topical retinoid (isotretinoin) (AVOID PREG) +/- Benzoyl peroxide cream (kills p.acnes, inflam inhib)
2) Azelaic acid (reduce skin cell accum in follicle, antibact, anti-inflam)
Mild/mod popular/pustular, scar risk =
1) Epiduo: Adapalene (topical retinoid) + BPO
2) Duac: Clindamycin (Abx) + BPO
Not responding/widely distributed =
1) Tetracycline (Abx) (GP stop after 3m)
- Macrolides: first line in preg
- Trimethoprim: first line in young children
- Topical Abx - chlorhexidine
Mod/severe acne in women =
- Dianette: cyproterone acetate + ethinyloestradiol (VTE risk)
Severe acne/mod not resp or starting to scar/psychological =
- Refer to secondary care: oral isotretinoin, high-dose oral Abx, Dianette with extra cyproterone acetate, short course oral steroids
Medical procedure
- Extraction
- Light therapy
Outline the aetiology and pathophysiology of psoriasis
Thought to be genetic that is triggered by environmental factors
Abnormal excessive/rapid growth of keratinocytes in the epidermal layer
- Every 3-5 days (rather than 28-30)
Injury to the skin - koebner phenomenon
Premature maturation of keratinocytes
- Induced by an inflam cascade in the dermis involving dendritic cells, macrophages, T cells
Meds (lithium, beta-blockers, antimalarials, ACEi, NSAIDs), infection (strep, HIV), stress, hypoCa, preg
Type 1 = early onset <30y, FH
Type 2 = late onset >40y, disease activity milder, guttate psoriasis less common
Describe the types of psoriasis
Plaque (90%) - red patched with white scales on top
Guttate - drop-shaped lesions (can be triggered by strep infections)
- common in children
Flexural - smooth red patches in skin folds (genitals, armpits)
Pustular - small non-infectious pus-filled blisters
Erythrodermic - widespread, can devel from other types
Seborrheic-like - red plaques with greasy scales in areas of higher sebum production (scalp, forehead, folds next to the nose, around the mouth, chest above the sternum, skin folds)
What are the signs and symptoms of psoriasis?
Skin - commonly extensor surfaces + scalp
• Bilateral erythematous, dry, itchy, scaly plaque
• Auspitz sign - removal of scales cause cap bleeding
Nails (50%) • Pitting • Whitening • Bleeding under the nails • Onycholysis - separation from bed
Fissured tongue
Psoriatic arthritis (15% of psoriasis cases)
• Painful joints, swollen, deformity
• RA-liked
• Monoarthritis, arthritis of distal phalanges
How is psoriasis best managed?
1) General = avoid precipitating factors, assess for psoriatic arthritis + CVD
- 2) Emollients (diprobase)
- 3) Vit D derivative + corticosteroid (calcipotriol) (hydrocortisone, betnovate, eunovate)
- 4) Refer to dermatology = Phototherapy (UVB light + photochemotherapy), acitretin (retinoids), methotrexate, ciclosporin, PD4 inhib apremilast, dimethyl fumarate
- 5) Biologics = 1st line Ustekinumab, 2nd line infliximab
Scalp psoriasis = potent steroid OD, descaling prior
** avoid PO/IV steroids –> pustular psoriasis
Outline Rosacea
Long-term skin condition - mainly affects the face, more common in women/lighter skin
S+S = flushing. persistent facial redness. visible blood vessels, PAPULES + PUSTULES, thickened skin, lymphoedema, rhinophyma
Mx =
- Sun block
- Emollients
- Mild: topical metronidazole
- More severe: PO Abx - tetracyclines
- B-blockers - blushing
- Isotretinoin - severe
- Lazar therapy
What are the possible SEs from roaccutane?
- Mucocutaneous reaction: Dry skin, dry lips, dry eyes
- Fragile skin; avoid waxing
- Increased risk of skin infect + slower wound healing
- Increased sensitivity to the sun
- Deranged LFTs
- Hypercholesterolaemia
- Hypertriglyceridaemia
- Myalgia
- Arthralgia
- Depression +/- self-harm + suicide
What are the possible complications of eczema?
Eczema herpeticum (due to herpes simplex)
Secondary bacterial skin infections (impetigo)
Impaired quality of life
What complications are associated with psoriasis?
Psoriatic arthritis
Metabolic syndrome (combination of DM, HTN, and obesity) - assess all RF when first see pt
