Allergic Skin Diseases Flashcards
Lesions of different eczema stages
- Acute stage :
ill-defined erythematous patches, papulovesicular
eruption with exudation of serum - Subacute stage : erythema and scaling
- Chronic stage : dryness and lichenification
List types of Endogenous eczema
• Atopic dermatitis
• Discoid eczema
• Pityriasis alba
• Stasis dermatitis
• Seborrhoeic dermatitis
• Dyshydrotic eczema (pompholyx)
Allergic contact dermatitis is type ….. hypersensitivity
Type 4 hypersensitivity (sensitization dermatitis)
Allergens in allergic contact dermatitis is
Incomplete antigens ( haptens )
Atopic Dermatitis often associated with
A personal or family history of allergy
Itching is the constant symptom, xerotic or dry skin with loss of barrier functions
In Infantile phase of AD lesions most frequently start on
Face
erythematous discrete or confluent edematous papules, intensely itchy, may become exudative and crusted
Sites mostly involved in Childhood phase
of AD
elbows and knee flexures, sides of the neck, wrists
and ankles and the hands.
erythematous, edematous papules which tend to be replaced by lichenification
sites mostly involved in neurodermatitis
Adulthood phase of AD
outer arms, upper back, and shin of the tibia.
lichenified plaques.
The only type of eczema with a
demarcated edge
Discoid Eczema
in adults on the extensor aspects of limbs
Lesions of Varicose Eczema (Stasis Dermatitis)
an erythematous scaly oozing area, surrounded by small slate blue macules resulting from hemosiderin deposits.
Ulceration around one of malleoli
Cause of Seborrhoeic dermatitis
(scaly erythematous dermatitis)
seborrhea, abnormal sebum composition and the lipophilic yeast Malassezia.
Lesion of Infantile SD
Greasy yellowish scales on erythematous area usually on the scalp (cradle cap), diaper area and intertriginous fold
Leison of Adult SD
scaly erythematous patches involving hairy areas
and body flexures as nasolabial folds
Lesion of Infective Eczematoid Dermatitis
area of erythematous patches with exudation and crustation around
a discharging focus
Cause of Dyshydrotic Eczema (Pompholyx)
In heavily perspiring individuals
as an allergic reaction to a distant focus of infection as tinea pedis.
Site of Pompholyx
acute or subacute vesicular eruption starting usually on the
sides of the fingers and toes and extending to soles
Lesion in Pityriasis Alba
rounded, oval patch or
erythematous plaques with fine
lamellar or branny whitish scaling in children leaving scaling and hypopigmentation
DD of Pityriasis Alba
Pityriasis versicolor
In alba lesion is ill-defined, skin is dry, more in children
TTT of Eczema
- Topical
- Acute eczema :
Compresses as potassium permanganate solution 1/8000 , 1/10.000 of lead subacetate solution 0.5% for oozing cases + topical corticosteroid cream
- subacute eczema: Corticosteroid creams.
- chronic eczema: Topical corticosteroid ointments
long-term use of emollients in atopic dermatitis - Systemic :
Antibiotics, Corticosteroids, Antihistamines
1ry leison of urticaria
Wheels
Layers involved in urticaria
Wheals in upper dermis
Angioedema in lower dermis and SC tissue
Immunologic (Allergic cause) of urticaria
classic type І hypersensitivity reaction
Mention different types of wheals
- Acute : idiopathic or following URTI
- Chronic : autoimmune process
- Physical : solar, cholinergic….
- Urticarial vasculitis : type III hypersensitivity reaction,more than 24h, causes: drugs, HCV and autoimmune
connective tissue disease
Management & TTT of urticaria
- 1st line : Non sedating antihistamines (second generation), daily for 2-3 weeks
- Ant-IgE (Omalizumab) or cyclosporin for chronic urticaria, SC monthly
- Systemic steroids : in severe acute urticaria for a short time
- Adrenaline 1/1000 1cc subcutaneously :
the first line treatment of anaphylaxis, angioedema and impending airway obstruction
(contraindicated in hypertension and heart disease).
PAPULAR URTICARIA is a type……hypersensitivity
type IV hypersensitivity to insect bites.
chronic and recurrent eruption of irritable edematous papules affecting infants and children.
Lesion of PAPULAR URTICARIA
Initially an extremely itchy edematous papule followed by a firm pruritic papule 5hat persistent for several days
Prurigo of Hebra is a
• Severe type of papular urticaria
insect bite reaction in atopic patientsdue to environmentalfactors (poor nutritional and hygienic condition)
TTT of Papular Urticaria
• Avoid insect bites and use insect repellant.
• Topical corticosteroids.
• Antihistamines.
• Short-term oral steroids for extensive and spreading lesions.
• Antibiotics in secondary infection.
• Soothing lotion as calamine lotion or other topical antipruritic
preparations.
• Change of environment in severe cases (Prurigo of Hebra)
Hallmark of the eruption in ERYTHEMA MULTIFORME
target or iris lesion ( circular erythematous leison with a vesicle or papule in center that is darker in color
Most common cause of ERYTHEMA MULTIFORME
hypersensitivity reaction to Infection by herpes simplex
Lesion of ERYTHEMA MULTIFORME
sudden onset of bilateral symmetrical multiform lesions including erythematous macules, papules, vesicles and sometimes bullae.
Treatment of the ERYTHEMA MULTIFORME
• Symptomatic treatment is sufficient for the usual attack.
• oral antihistamines reduce stinging & burning
• Short-term oral steroids in moderate to severe cases.
• In case of recurrent EM secondary to HSV: oral acyclovir at 10 mg/kg/d for 6-12 weeks may be considered as a
prophylactic treatment.
Lesion of Stevens Johnson Syndrome
Flu like symptoms followed by painful red or purplish rash blisters with shedding of top layers
Eye affection in SJS
A severe catarrhal or purulent conjunctivitis.
If 30% affected of body surface: Toxic epidermal necrosis
Complications of Stevens Johnson Syndrome
Secondary skin infection(cellulitis)
• Sepsis.
• Eye problems extensive tissue damage and scarring up to blindness
• Damage to internal organs as pneumonitis, myocarditis, nephritis
and hepatitis.
• Death may occur in 5-15% of untreated cases.
Treatment of SJS
Admission to an intensive care unit
Treatment of the cause and discontinuation of the offending drugs.
Systemic steroidsIntravenous
Immunoglobulins (IVIG)
Etiology of ERYTHEMA NODOSUM
A type of hypersensitivity reaction to
Streptococcal infection
Tuberculosis.
Sarcoidosis
Chlamydia.
Viruses as HBV
Deep fungal infection.
Sulphonamides and oral contraceptives.
Ulcerative colitis.
Malignancies
Leprosy : erythema nodosum leprosum representing acute panniculitis of leprosy.
Idiopathic
Leison of ERYTHEMA NODOSUM
multiple bilateral, tender, warm, erythematous nodules (may be ecchymotic) mainly on the anterior aspects of the lower limbs.
Treatment Of ERYTHEMA NODOSUM
• Rest in bed
• Analgesics
• Antibiotics
• Acetyl salicylic acid
• Systemic steroids in some cases
• Treatment of the actual cause.
Leison in Fixed Drug Eruption
eruption is sharply marginated rounded or oval erythematous patches which becomes dusky violaceous in color.
Comments sites : Penis, lips, dorsum of hands
Healing leaves permanent slate blue discoloration.
Drugs causing FDE
sulfonamides and analgesics.
The comments site of Infantile eczema
Face
