dermatology Flashcards
What are the skin physiological changes in pregnancy
increased pigmentation - begins T1 and fades after delivery
Melasma - brown pigmented spots 70% of woman, in the second half of pregnancy -forehead, cheeks, lip, skin
Spider naevi - face, trunk, arms, T1 throughout, 25% persist
Palmer erythema 70% fades PP
Hair loss - telogen effluvium occurs 4-20 weeks post partum, hair is in the anagen phase in pregnancy and converts into the telogen resting phase. Lost diffusely but recovers 6/12 post partum
Striae gravidarum - more so if obese and twins
Reduction of cell mediated immunity in pregnancy increases the prevalence of skin infections
Puritis 20% pregnancies
How does pregnancy affect pre - existing skin conditions
eg eczema and psoriasis acne
Shift from T helper 1 lymphocyte dominant to T helper 2 cell dominant
eczema often worsens (T helper 2 driven) - 20% of woman have a flare
psoriasis improves (T helper1 driven)
acne can worsen in T3 as there are more circulating androgens
Psoriasis in pregnancy
How does pregnancy affect it
How is it treated
For most woman it improves
10-20% deteriorates
Emollients, calcipotriol, and low to mid potency steroids are first line
Second line - narrow band ultraviolet B, or broadband UVB
Third line ciclosporin and antiTNFa are safe
MTX is not safe can cannot be used
Impetigo Herpetiformis is a rare pustular form of psoriasis How does it present? How does it affect the pregnancy? how to treat it? does it recur?
Urticated erythema starting in the flexures
sterile pustules
widespread and effect the mucosa
Severe systemic unwellness including fever and neutrophilia, hypocalcaemia
Risk LBW babies
Treat with systemic corticosteroids
regular fetal surveillance
oftens recurs
How does acne rosacea change in pregnancy and how do you treat it
It worsens in pregnancy
Tx with topical azelaic acid, erythromycin or narrow band UVB
What is erythema nodosum how does it present What do you need to rule out How is it treated what is the prognosis
It is inflammation of the subcutanous fat presented as tender nodules over the lower legs
TB and sarcoid may be excluded on CXR
Hx of strep infection, inflammatory bowel disease, or medications (particular sulphonamides)
If no underlying cause prognosis is excellent and they will resolve after 2 months
severe cases can be tx with systemic corticosteroids
What is erythema multiforme
how does it present
what can precipitate it
acute self limiting condition
Peripheral symmetrical eruption of erythematous papules central pallor with concentric rings
Can be from HSV or drug use
What is pityriasis rosea
self limiting non recurring rash on trunk and proximal limbs
Oval reddish brown scaley lesions
May be a relationship to human herpes virus 6
PEP - polymorphic eruption of pregnancy Incidence time of onset Who gets it Distribution What does it look like How does it affect the fetus resolution treatment
1:200
Mean from 34 weeks
70% primips 13% multiple pregnancy
Umbilical sparing, abdomen along striae under the breasts and arms, thighs
Puritic urticarial papules and plaques, erythema and rarely vesicles, target lesions
no fetal affect
Rapid resolution after delivery
menthol 1% in aqueous cream - apply when cold
hydrocortisone 1%
sedative antihistamine - phenergan (promethazine) 25mg nocte
non sedating antihistamine like loratadine
Only occasionally systemic steroids
rarely recurs
Pemphigoid gestationis Incidence Timing Who gets it Eruption and distribution What conditions is ti associated with
1:10 000
any time 9 weeks to 1 week post partum - usually T3
Abdomen, umbi affected, spreading to limbs and soles
anyone gets it
Intensily puritic, urticated erythematous papules, target lesions, annular wheals, after variable delay usually 2 weeks vesicles and large tense bullae form
If in T2, it relapses post partum
Papules can persist for months
Can become bullous pemphigoid
Associated with graves, vitiligo, T1DM and RA
Pemphigoid gestationis
What is the pathophysiology
Autoimmune condition possibly related to the exposure of fetal antigens
Binding of compliment fixing IgG antibodies to a protein called bullous pemphigoid antigen 2 in the hemidesmosomes of the basement membranes triggers an immune response
Pemphigoid gestationis
how is it diagnosed
Skin biopsy and direct immunoflorescence which shows C3 deposition in the basement membrane
in 30-100% of cases the antibodies can be detected in the serum by indirect immunofloresence
Pemphigoid gestationis
how does it affect the fetus
LBW
PTL
IUD
10% cases the neonate had bullous eruption, this is mild and transient
Pemphigoid gestationis
Treatment
recurrence
Tx - potent topical steroids eg 0.1% mometasone furoate
Most require systemic steroids
sedative antihistamine
Usually recurs, may recur with the OCP
Atopic eruption of pregnancy Incidence time of onset Who gets it Distribution What does it look like How does it affect the fetus resolution treatment
1:300
75% before T3 - earlier then PEP
mostly multips 20% hx eczema
Eczema changes at typical sites (flexures, face, neck)
eczematous, papular or puritic lesions
improves after delivery but can persist for several months
Associated with atopy
no fetal consequence
Tx - emmolients, topical steroids atihistamines
