This is long but advice on skin rashes in pregnancy:
What are abnormal skin conditions in pregnancy?
Skin disorders that occur during pregnancy can be:
rashes specific to pregnancy, called specific dermatoses (skin disorders) of pregnancy.
non-specific rashes that could occur at any time.
itching without rash.
These disorders can cause harm to mother and baby, so seek medical advice if you spot any skin changes that seem abnormal. Itching without rash can be normal or abnormal in pregnancy. Advice should be sought if itching occurs after the first trimester (three months) of pregnancy, or if it keeps getting worse.
Specific dermatoses of pregnancy
Rashes that only occur in pregnancy are:
PUPPP - (pruritic urticarial papules and plaques of pregnancy)
herpes gestationis
impetigo herpetiformis
papular dermatitis of pregnancy
prurigo gestationis.
Non-specific rashes during pregnancy
Any skin disorder can appear during pregnancy. Causes of rashes include allergies, medicines, insect bites, skin infections, viral infections, parasites, tumours, and a group of diseases that affect the whole body known as connective-tissue disorders.
These rashes can affect any person at any time, not specifically pregnant mothers. However, pregnancy can change the appearance and consequences of these rashes, and the condition causing the rash may also have harmful effects on the pregnancy.
Itching without rash during pregnancy
Sometimes during the first trimester (three months) of pregnancy, you can experience mild itching without a rash. If this itching persists after the first trimester, or if it keeps getting worse, report the symptom to your doctor, midwife, or other health-care practitioner.
Some pregnant women experience severe itching during the third trimester of pregnancy. This symptom can be due to a condition called intrahepatic cholestasis of pregnancy (ICP).
Mild jaundice (yellow colouration of skin and eyes) can also occur in this condition. Both the itching and the jaundice occur because during pregnancy the liver becomes up to 30 times less efficient at getting rid of bile (a greenish-yellow fluid that is partly a waste product, and partly used to digest fat).
When to seek advice
Some conditions that cause rashes are dangerous to the mother as well as the baby, so seeking early advice is important for any skin change that seems abnormal, particularly if the pregnant woman feels unwell.
Early diagnosis and treatment are essential in many of these conditions.
PUPPP - (pruritic urticarial papules and plaques of pregnancy)
This condition is the most common dermatosis (skin condition) of pregnancy. The cause was unknown until recently when Dr Selim Aracting and colleagues from France reported studies linking PUPPP with cells from the developing baby (foetus). Their studies suggest that foetal cells can invade the mother's skin during pregnancy, and in some way cause this skin disorder to develop.
Symptoms and signs
What red raised spots or bumps that itch strongly.
Where the rash usually starts on the abdomen and spreads to the thighs. Occasionally, the rash spreads to arms and buttocks. The face is never involved.
When the rash usually appears after 34 weeks of pregnancy and disappears after childbirth, but can recur with subsequent pregnancy.
Complications
This condition causes no harm to mother or baby.
Treatment
Corticosteroids applied to the skin (topical) are known to give prompt relief.
Sometimes oral corticosteroids (eg prednisolone) are needed.
Papular dermatitis of pregnancy
Abnormal blood hormone levels are linked with this disorder especially chronically raised levels of gonadotrophins (hormones produced by the pituitary gland of the brain, and which regulate sex hormone levels) and lowered cortisol and oestrogen levels.
Symptoms and signs
What: an extremely itchy rash consisting of red, raised spots that look like insect bites. Crusts (scabs) cover some of these spots. The spots do not collect in groups.
Where: all over the body.
When: this rash can erupt at any time during pregnancy and then spots continue to appear until childbirth when they clear rapidly.
Complications
This condition causes no complications in the mother, but studies suggest that foetal death rates are increased.
Treatment
High doses of corticosteroids are necessary.
Prurigo gestationis
This rash comes in two forms: an early form and a late form.
Symptoms and signs
What: very itchy red dots.
Where (early form) : upper trunk and upper parts of arms and legs. In this form, the abdomen and buttocks are rarely involved.
Where (late form): the rash is found mostly on the abdomen, usually on striae (stretch marks). After delivery, this form may spread to the entire body.
When: the early form appears in the middle months of pregnancy, while the late form occurs in the last week of pregnancy. The rash completely clears within three weeks after childbirth.
Complications
This condition is generally not associated with any serious complications in mother or baby.
Treatment
Simple measures like antihistamine tablets.
Herpes gestationis
Herpes gestationis is a rare disease that is not related to the viral infection herpes simplex.
Symptoms and signs
What: a moderate-to-severe itchy rash consisting of different types of lesion (raised dots or bumps, fluid-filled blisters or blebs, or a combination).
Where: usually seen on the abdomen, particularly around the navel, and also on arms and legs. Palms and soles are frequently affected. The entire body may also be involved.
When: most likely to appear during the fourth and fifth month of pregnancy, but can occur before or after. This condition can be seen in the first pregnancy or in successive pregnancies for the first time.
Complications
This disease can have severe complications. The mother can develop necrosis (breakdown and death) of affected skin as well as kidney damage, which is diagnosed when blood and protein are found in the urine.
Infants can be born with this rash, but it usually clears up within a few weeks of birth without treatment.
Treatment
Corticosteroids by mouth (systemic). Pyridoxine has also been reported to be effective.
Impetigo herpetiformis
Impetigo Herpetiformis is an acute but rare skin condition of pregnancy.
Symptoms
What: groups of small, pus-filled blisters that develop irregularly or in curved or spiral-shaped clusters. After a few days, the blisters scab and the rash dries up, then new blisters appear at the edges of the dried-up rash. Several circles of this type may be produced as the disease progresses. Mild itching, burning sensations and hair loss can occur in the involved area. The rash is always accompanied by severe illness, such as chills, fever, vomiting, diarrhoea and joint pains.
Where: usually begins in groins, underarms, and the folds of knees and elbows. The disorder can affect the mucous membranes of the mouth and genitals where it looks like a greyish erosion (shallow ulcer).
When: usually begins in the last trimester and disappears after childbirth, although sometimes it leaves residual marks or scars.
Complications
If this disease is not treated promptly, the maternal death rate is high, and so too is the rate of stillborn babies.
Treatment
Early diagnosis, and prompt and intensive treatment is advisable.
Good responses have been reported with ACTH (adrenocorticotrophic hormone, which stimulates the body to produce more steroids from the adrenal glands)and cortisone treatment.