White : Diseases of the Skin - Blistering Disorders

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Gary M. White & Neil H. Cox

Diseases of the Skin

16	Blistering Disorders

MECHANICAL AND PHYSICAL CAUSES OF BLISTERING

Traumatic causes of blistering

The commonest causes of blistering are those due to simple physical, chemical, or thermal trauma. Blisters due to friction or burn injury (Fig.16.2) are most common in the community but are generally not seen by dermatologists. Cold injury (including therapeutic cryotherapy) and pressure are less common causes.

Edema of the lower leg (Fig.16.3) is a very under-recognized cause of blistering, which is most apparent in the elderly. It typically occurs when the edema has developed rapidly, for example as a result of stopping diuretic therapy. Blisters are confined to the lower leg and have clear fluid content (at least initially). The main differential diagnosis is from bullous pemphigoid.

Epidermolysis bullosa

The major mechanobullous disorders are those in which there is an inherited defect in structures such as hemidesmosomes or anchoring fibrils, making the skin more fragile and susceptible to mechanical stimuli that produce blisters, notably friction and other direct trauma (Fig.16.4). This group of disorders, collectively known as epidermolysis bullosa, is discussed in Chapter 19.

Table 16.1 CAUSES OF BLISTERING

Category	Cause
Physical	Friction, burns, pressure, edema (Figs 16.2 – 16.5) Miliaria (Ch. 23)
Inherited	Epidermolysis bullosa (mild physical damage, inherited predisposition to blistering) Hailey–Hailey disease (Fig.16.39 and Ch.19)
Inflammatory	Eczemas, pompholyx (Ch. 6), drug and plant phototoxicity (Ch.17) Erythema multiforme and Stevens–Johnson syndrome (Ch.11), toxic epidermal necrolysis (Ch.18) Fixed drug eruption (Ch.18) Vasculitis (Ch.14) Neutrophilic dermatoses (Sweet disease, pyoderma gangrenosum, subcorneal pustular dermatosis; Ch.14) Rare variants of systemic lupus erythematosus (Ch.13), lichen planus (Ch. 8), lichen sclerosus (see Fig.16.13)
Infections	Bacterial (Ch. 24): staphylococci (impetigo, staphylococcal scalded skin, blistering distal dactylitis), streptococci (impetigo, cellulitis, blistering distal dactylitis) Viral (Ch. 25): herpesviruses (herpes simplex, varicella, herpes zoster), hand foot and mouth disease, orf
Bites and infestations	Insect bites or papular urticaria Scabies (Fig.16.10 and Ch. 27)
Immunobullous	Pemphigus, pemphigoid, cicatricial pemphigoid, dermatitis herpetiformis,
Metabolic	Porphyria, pseudoporphyria (Ch. 17), cutaneous amyloidosis (Ch.11)

Figure 16.1 Structures of the dermo–epidermal junction (basement membrane zone).

Figure 16.2 Thermal burn on the abdomen due to boiling water spilt from a kettle. The linear shape at the site of constriction of the waistband suggests an external cause, and there was sparing in the area of the patient’s underclothing due to the protection given by the additional layer of thicker material.

Figure 16.3 A tense unilocular blister with clear fluid content and featureless background on the lower leg due to rapid development of edema of the leg. In some such instances, there may be an asteatotic eczema appearance; in longstanding edema, there may be marked redness as well.

Figure 16.4 Patients with epidermolysis bullosa blister easily as a result of injury, in this case the combination of trauma and the handling required during orthopedic surgery.

Epidermolysis bullosa acquisita is an unrelated immunologically mediated disease in which skin fragility is a prominent feature, discussed later in this chapter.