Acute And Chronic Dermatoses PDF

Acute and Chronic dermatoses: Acute:- Lasts days to weeks. Inflammatory infiltrate. Edema Epidermal vascular subcutaneous injury. Urticaria Eczematous Erythema Multiform Localized Mast cells...

Acute and Chronic dermatoses: Acute:- Lasts days to weeks. Inflammatory infiltrate. Edema Epidermal vascular subcutaneous injury. Urticaria Eczematous Erythema Multiform Localized Mast cells Haptens → neoantigen → Hypersensitivity reaction to degranulation. Langerhans cells → lymph certain drugs & infections...’’.. dermal microvascular node → T cells. hyperpermeability. Immunologically mediated epidermal cell injury. lesions:- Pruritic edematous plaques Initial erythema Macules = wheals. Pruritus Papules Red papulovesicular Vesicles Oozing rash Bullae Vesicles Targetoid lesions. crusted lesions. Symmetrical extremity edema involvement. After :- Acute graft vs host Disease Skin allograft rejection Fixed drug eruption. Acute 6w Face Flexor surface Associated with: Angioedema ← Asthma Stevens - Johnson syndrome. complement mediated. Allergic rhinitis → in children. Age:- 20-40y Self limited Develop & fade within hours. Develops in any area of pressure. Pathophysiology Antigen induced release of T-cell mediated inflammation. CD 8 cytotoxic T cells : vasoactive mediators from Keratinocyte injury mast cells. Type 4 hypersensitivity. Type 1 hypersensitivity. 1. Allergic contact dermatitis. 1. Infection of HSV, Drugs 2. Atopic dermatitis = Eczema Mycoplasma, Histoplasmosis, Inherited deficincey in C1 X. 3.drug related dermatitis. coccidioidomyocsis, typhoid, 4.photoeczematous leprosy. Ig E dependant dermatitis. 2. Drugs :- Sulfonamides, Ig E independant 5. Primary irritant dermatitis. penicillin, barbiturates, Complementary activation. salicylates, hydantoins, antimalaria. Mast cells release IL-4 & 3. Cancer :- carinoma & 13!! lymphoma 4. Collagen vascular Diseases= SLE, dermatomyositis, polyarteritis nodosa. Histo :- Mononuclear cells Acanthosis Lymphocyte infilteration eosinophils. Widely spaced Hyperkeratosis Edema collagen. Edema in stratum spinosum Edema & lymphocytes accumulation on dermoepidermal junction. Gross :- Wheal lasts for 24h. Red papules Superficial perivascular Lymphocytic infiltrate Vesicles Degradation & necrotic Oozing & Crusting keratinocytes = Interface dermatitis. Upward migration of lymphocytes to epidermis = blister. Targetoid lesions CD8 in the central portion & CD4 T helper cells & langerhans cells in the raised erythematous periphery. Complication : Bacterial superinfection Toxic epidermal necrolysis. Steven’s -Johnsons Treatment : Anti histamines Topical steroids systemic corticosteroids Avoid the cause Omalizumzb Chronic : Months to years. Changes as in epidermal growth. or Dermal fibrosis. The skin surface is roughed as a result of excessive or abnormal scale formation & shedding. Hereditary ichthyoses with extensive scale d/t defects in desquamation. Lichen planus Seborrheic dermatitis Psoriasis Self limited & resolves in 1-2y. Autoimmune Age:- Infants & adults Tongue twister of 6ps. HLA-Cw 0602 allele Risk of → squamous cell Dandruff Koebner phenomenon carcinoma Affects:- High density sebaceous glands Scalp forehead retroarticular area Nasolabial folds Presternal area External auditory canal Lesion:- Pruritic Well demarcated plaques Well demarcated Purple Greasy yellow scales on areas with Pink to salmon color plaque Polygonal planar sebaceous glands Loosely adherent scale Papules & plaques Silver white in color. Site :- Wrist & elbow Face scalp periocular region Knee & elbow Glans penis Scalp lumbosacral Oral mucosa intergluteal cleft glans penis extensor surfaces Darkly pigmented lesions Macules Erythroderma Papules Oncholysis Oral lesions= Reticular white On erythematous yellow greasy Pustular psoriasis lines = Wickham striae base Bleeding spots Extensive scaling & crusting. Zones of postinflammatory Life threatning :- hyperpigmentation Fever Leukocytosis Itchy violaceous flat topped Arthralgia papules → plaques Diffuse cutaneous & mucosal pustules Secondary infection Electrolyte imbalance. Associated Hepatitis C HIV infection Arthritis with: Parkinsons Diseases with Myopathy increased sebum Enteropathy Ketoconazole = antifungal. Spondylitic joint Disease Malassezia furfur AIDs Children :- Diarrhea & failure to thrive Histo :- Hypergranulosis Parakeratosis Acanthosis Sawtooth infiltrate of Rete Follicular lipping Parakeratosis ridges. Perivascular inflammatory infiltrate Rete bridges low → neutrophils & lymphocytes Thin or absent stratum Infiltrate of lymphocytes granulosum. Along the dermoepidermal HIV pt:- Increase stratum spinosum junction. Apoptotic keratinocytes & plasma High mitosis above basal layer. Degeneration necrosis cells Dilated blood vessel Saw tooth appearance d/t the Elongation of dermal papillae. lymphocyte infiltrate. Chronic :- Anucleate Necrotic basal cells Hypergranulosis Hyperkeratosis Lichen planopilaris Special :- Civatte bodies Auspitz sign = pinpoint bleeding. Spongiform pustules Munro micro abscesses Pustular psoriasis Gross :- Salmon colored plaques Scale = silver white Treatment Topical antifungals & Anti -TNF : glucocorticoids. UVA Corticosteroids PUVA