Infant rashes
Created: 09.01.2025
Updated 09.01.2025
What are infant rashes?
Infant rashes are extremely common, particularly during the first weeks and months of life. Newborn skin is thin, sensitive, and still adapting to life outside the womb. As a result, many babies will develop rashes that can look alarming but are usually temporary and harmless.
Most baby rashes do not cause discomfort and settle without treatment. However, some skin rashes may require assessment to exclude infection, allergic reactions, or underlying skin conditions. This guide outlines the most common rashes seen in infants and explains when specialist dermatology advice is recommended.
Why do babies develop rashes?
Infants are more prone to skin rashes because:
- Their skin barrier is immature
- Blood vessels are close to the skin surface
- Sweat glands are not fully developed
- Hormonal changes occur after birth
- The immune system is still developing
Most infant rashes are part of normal skin adaptation rather than a sign of disease.
Marbling of the skin (Livedo reticularis)
Marbling of the skin is not a true rash. It appears as a purplish, bluish, or lace-like pattern caused by temporary changes in blood flow within the skin.
This occurs because an infant’s blood vessels constrict in response to cold. It is commonly seen on the arms and legs and usually resolves when the baby is warmed. Marbling is most noticeable in the first weeks or months of life but may persist intermittently into early toddlerhood.
If marbling is persistent, widespread, or associated with other symptoms, medical review is advised.
Harlequin colour change
Harlequin colour change is a striking but harmless phenomenon in which one side of the baby’s body suddenly becomes red while the other remains pale. It is caused by temporary imbalance in blood vessel tone.
This affects around 10% of newborns, typically occurs during the first days of life, and resolves spontaneously within minutes. It usually disappears completely within a few weeks and requires no treatment.
Erythema neonatorum
Erythema neonatorum is one of the most common newborn rashes. It appears as red patches, sometimes with small white or yellow spots, and usually develops within the first few days of life.
More than half of all newborns are affected. The cause is unknown but is thought to reflect normal immune system activation. The rash resolves on its own within days to weeks and does not indicate infection or allergy.
Baby acne (Neonatal acne)
Neonatal acne affects around 20% of babies. It appears as small white or red pimples, most commonly on the cheeks, forehead, and nose.
It is caused by hormonal stimulation of the sebaceous glands after birth. Baby acne is harmless and does not predict acne later in life. The recommended approach is no treatment, as the rash usually clears within weeks to months. Products and squeezing should be avoided.
Milia
Milia are small white or yellow bumps, commonly seen on the nose, cheeks, forehead, and chin. They are caused by trapped keratin within the skin.
Milia affect around half of all newborns and typically resolve on their own within the first few months of life. They are harmless and should not be squeezed or treated.
Heat rash (Miliaria)
Heat rash occurs when immature sweat ducts become blocked, preventing sweat from escaping. This leads to small red bumps or clear blisters, often on the neck, chest, or skin folds.
Heat rash is common in warm environments or when babies are overdressed. Although it can look uncomfortable, it is usually mild and settles once the skin is cooled. Dressing babies in light clothing and avoiding overheating helps prevent recurrence.
Cradle cap (Seborrhoeic dermatitis)
Cradle cap presents as greasy, yellowish scales on the scalp and sometimes the face, chest, or skin folds. It is a very common infant skin condition and does not usually itch or cause distress.
Cradle cap often improves gradually over the first year of life. In persistent or widespread cases, treatments such as medicated shampoos, antifungal creams, or mild topical corticosteroids may be recommended under medical supervision.
Atopic dermatitis in infants
Some infants develop atopic dermatitis (https://www.skindoc.uk/services/atopic-eczema), a chronic inflammatory skin condition associated with dry, itchy skin and a family history of eczema, asthma, or allergies. Unlike many neonatal rashes, atopic dermatitis tends to persist and may worsen over time.
Atopic dermatitis often affects the cheeks, scalp, and extensor surfaces in infancy. Early dermatology input can help manage symptoms and reduce complications.
When should parents seek medical advice?
Most infant rashes are harmless. However, immediate medical attention should be sought if a rash:
- Is associated with fever, lethargy, or poor feeding
- Spreads rapidly or becomes painful
- Shows signs of infection such as pus, crusting, or swelling
- Is accompanied by breathing difficulty or swelling of the lips or eyes, which may suggest allergic reactions
- Does not improve or worsens despite basic care
Specialist dermatology assessment is particularly helpful when the diagnosis is unclear or when a rash is persistent, severe, or recurrent.
Frequently asked questions
How can I tell if my baby’s rash needs medical attention?
Seek medical advice if the rash is accompanied by fever, lethargy, poor feeding, rapid spreading, pain, or signs of infection such as oozing or swelling. Immediate medical attention is needed if there are breathing difficulties or facial swelling, which may indicate an allergic reaction.
Is baby acne the same as allergic reactions?
No. Neonatal acne is caused by normal hormonal changes and is not related to allergies. Allergic reactions often cause an itchy rash, swelling, or widespread redness and usually appear after exposure to a new product or food.
Can infant rashes be a sign of atopic dermatitis?
Yes. Some infants develop atopic dermatitis, which tends to cause dry, itchy, and persistent rashes, often on the cheeks or scalp. Unlike many newborn rashes, atopic dermatitis may continue beyond infancy and benefit from specialist care.
Should infant rashes be treated with creams or medications?
Most infant rashes do not require treatment. Using gentle skincare and avoiding overheating is usually sufficient. Medicated creams should only be used if advised by a healthcare professional, as inappropriate treatment can irritate sensitive infant skin.
