Introduction
Sucking blisters are the blisters caused as a result of the vigorous sucking of a baby while it is in the uterus. This is because of the overuse of the orbicularis oris, the lip muscle. The orbicularis oris muscle gives the lips their form and shape. Sucking blisters become evident when sucking is aggressive in utero (inside the uterus). They are commonly found on the baby’s arms, fingers, and other body parts that could suck in the uterus.
What Are Sucking Blisters?
A skin condition in the newborn, particularly because of the sucking activity in the uterus, is called a sucking blister. It is a rare condition in less than one percent of newborns. Understanding the condition is difficult, as it can resemble many other blisters. A sucking blister is diagnosed only after ruling out other skin conditions that might cause blisters. This is usually self-limiting and would disappear as the baby stops sucking the area.
How Is Sucking Blisters Different From Sucking Pads?
Sucking blisters are usually seen as benign erosions in the area where a baby could suck while in the uterus. Sucking pads are thickenings found in the lips due to increased keratin deposition. This can also be due to an aggressive sucking reflex. The two conditions should be diagnosed only after excluding other systemic and skin conditions that may cause similar lesions.
How Are Sucking Blisters Seen Clinically?
When a baby in the womb sucks aggressively, it can cause blisters in those areas like the forearm, fingers, and hands. Its diameter usually ranges in size from 0.5 cm to 1.5 cm. They are generally seen in one area the baby used to suck, though in some cases, multiple areas have also been noted. There is no difference in the severity of the blisters to an increase in the number.
These blisters are usually oval-shaped with thick walls and may contain a sterile fluid inside. Sometimes, it is seen as erosions of the skin with demarcated borders. The size may vary from 0.5 cm to 2 cm. A study in 1963 reported that sucking blisters were seen in 1 in 200 and 50 births.
What Are the Differential Diagnosis of Sucking Blisters?
Sucking blisters can be confirmed only after excluding their differential diagnoses. It can be diagnosed based on similar lesions in other parts of the body, the onset time, whether it resolves independently, etc. The most useful clue for confirming the diagnosis is noting the newborn trying to suck these areas intensively. However, there can be other infectious or non-infectious conditions that may be similar to a sucking blister. They may or may not have other systemic findings. Some differential diagnoses include;
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Congenital Herpes Simplex Infection: It is a rare condition where the herpes simplex virus is transferred from a pregnant mother to the baby.
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Neonatal Varicella: This is an acquired condition when the pregnant mother gets varicella (or chickenpox) infection in the last three weeks of pregnancy.
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Bullous Impetigo: A bacterial infection (usually staphylococcal) seen as painful blisters that can be irritating and itchy.
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Congenital Syphilis: A condition when a pregnant mother infected with syphilis passes the infection to her child.
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Congenital Candidiasis: This is a rare condition seen within the first six days after birth. An intrauterine candidal infection causes the condition.
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Neonatal Lupus Erythematosus (NLE): It is an autoimmune condition seen in a baby born to a mother with anti-Ro/SSa antibodies. The affected child can have rashes in the body with other systemic conditions.
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Hereditary Bullous Diseases: They are rare skin conditions caused by mutations in structural proteins required for intraepidermal adhesion and dermo-epidermal anchorage of the skin (both of which are required for skin integrity).
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Epidermolysis Bullosa: It is a rare condition that causes blisters on the skin.
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Mastocytosis: A rare condition caused by many mast cells in a tissue.
What Are the Other Conditions Where the Baby Overuses Their Lips?
Babies tend to overuse their lips as other parts of the oral cavity are still developing and may lack coordination. Several other reasons why they overuse their lips include;
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Shallow Latch: A shallow latch occurs when the baby does not open their mouth wide to take in sufficient breast tissue during feeding. This can be rectified by teaching the baby to open wide for feeding.
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Premature Birth: A baby born before 37 weeks of pregnancy is called a premature baby. A premature baby may not be well developed to be fed by the mouth; rather, it is when the umbilical cord is used to feed the baby. Their organs and other body parts might be developed, but feeding can be problematic as their brain is not yet developed for a healthy eating pattern. Premature babies do not have buccal fat pads that are usually developed in the last weeks of pregnancy. These fat pads are designed to help them suck as they feed. Premature babies use more force on their lips, which can result in a sucking blister.
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Oral Restrictions: A lip tie, tongue tie, or buccal (cheek) tie is often called oral restriction. When the tongue, cheek, or lip is compromised of its function, the baby uses other muscles to help them accomplish feeding. Hence, the lips have to work more efficiently for feeding. This can cause a sucking blister.
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Cranial Nerve Dysfunction: When a nerve that helps in sucking is temporarily jammed during the birthing process, certain muscles, like the tongue, and cheeks might not work properly as expected. This causes an increased burden on the lips to compensate for the work of other muscles. This can lead to sucking blisters.
Conclusion
Since a sucking blister is a very rare condition, knowledge about the condition is also limited. In spite of it being a harmless condition, it can be a concern and cause anxiety to new parents. A physician familiar with the condition will be able to guide the parents, but necessary diagnostic steps to rule out other similar conditions must be carried out.
