Blisters are small fluid-filled sacs that appear on the surface of the skin. They may vary in size from pinpoint to 10mm in diameter. Larger blisters are known as bulla, whilst the smaller ones commonly seen in eczema are called vesicles.
Blisters are caused by an allergic reaction, which causes an increase in fluid accumulation in the skin’s tissues. Blisters usually break easily releasing their fluid onto the skin’s surface. When the fluid dries yellow crusts like scabs may remain on the skin.
Although not commonly recognised as a main symptom of eczema blisters can be present in most types of eczema. They are however mainly associated with Dyshidrotic eczema, Nummular eczema and Atopic eczema may also have blisters but they are a less distinctive part of the conditions.
Dyshidrotic eczema is a vesicular form of eczema affecting the hands and feet. The cause is unknown, both men and women are affected and the condition usually appears before the age of 40. As in general eczema the condition usually runs in families.
The condition is characterised by the sudden onset (1 – 3 days) of deep-seated small, clear, fluid filled blisters or vesicles. A rash may also develop. The main complaint is a burning sensation and intense itching.
This may be followed in the later stages by redness, scaling and thickening of the skin. The skin will also become cracked and large blisters will cause pain. Ruptured blisters will frequently result in a secondary bacterial infection developing.
Nummular eczema is a chronic dermatitis, which presents itself as stubborn coin shaped lesions. The lesions are red, inflamed and scaly. They are often accompanied by vesicular eruptions or blisters.
The lesions are usually wide spread on the arms and legs. Typical of any eczema the cause of the nummular form is unknown and there is no known cure. It is most common in older people especially if they have excessively dry skin.
As the condition clears the lesions heal from the inner skin layers to the outer. They look like red rings not unlike ringworm.
Atopic eczema is the most common form of eczema. The cause is unknown, but the condition is allergy based and tends to run in families. Children are most commonly affected by atopic eczema however it can continue into adulthood or first show up later in life.
In atopic eczema the skin becomes extremely itchy and inflamed, causing redness, swelling, weeping and scaling. Fine, red bumps or blisters may appear with associated oozing and crusting. The skin will become red and inflamed around the blisters. The areas most commonly affected are the head, face, neck, arms and in skin folds like behind the knees and in the folds of the elbows.