White : Diseases of the Skin - Blistering Disorders

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Gary M. White & Neil H. Cox

Diseases of the Skin

16	Blistering Disorders

INFECTIVE CAUSES OF BLISTERING

Bacterial infections

Infections that may cause blisters or pustules are numerous; see Chapter 24. The most common are staphylococcal infections (local blistering in impetigo, more widespread toxin-mediated blistering in staphylococcal scalded skin syndrome (SSSS), Figs 16.5 and 16.6) and streptococcal infections causing erysipelas or cellulitis.

Staphylococcal scalded skin syndrome is due to toxin-producing staphylococci. It is usually manifest only in children or in immunosuppressed or renally impaired adults, but occurs occasionally in healthy adults. The main differential diagnosis is toxic epidermal necrolysis.

Viral infections

These are discussed in more detail in Chapter 25. Herpes infections such as herpes simplex or varicella zoster typically produce vesicles or blisters (Figs 16.7 and 16.8).

Figure 16.5 Localized impetigo in the groin of an infant. Blisters in impetigo are superficial and rupture easily, but a rim of old blister is clearly visible.

Figure 16.6 Staphylococcal scalded skin syndrome (SSSS) is an exotoxin-mediated blistering eruption due to staphylococcal infection. It usually occurs in children, but may occur in adults who have impaired renal function (the toxin is excreted in urine) or who are immunosuppressed. This patient was a rare example of adult SSSS with neither of these background factors, but with a severely infected hip wound. See also Chapter 24.

Bites and infestations

A number of venomous bites from spiders and insects may cause blisters, some of which may be necrotic. Several biting insects cause an eruption known as papular urticaria, which generally occurs on the legs (Fig.16.9).

Pustules or blisters on the soles of the feet in infants are strongly suspicious of scabies (Fig.16.10), which is discussed in Chapter 27.

PRACTICE POINTS

•	lower leg edema is a common and under-recognized cause of blistering, usually in elderly patients and usually occurring when the edema has developed rapidly.
•	Extensive superficial blistering in an unwell child with no previous blistering problem is likely to be staphylococcal scalded skin; prompt antistaphylococcal antibiotic therapy is required.
•	Blisters on the soles of the feet of an infant are strongly suggestive of scabies.

Figure 16.7 Herpes simplex: a localized area of erythema with closely clustered, uniformly sized vesicles.

Figure 16.8 Herpes zoster affecting the C8 distribution of the hand. The blisters are often larger than in varicella.

Figure 16.9 Papular urticaria may have a mixed morphology, with papules, crusted lesions, and blisters. In this case, the blisters do not have apparent background inflammatory changes. A typical pattern is one of scattered lesions on the lower legs, and most cases occur in the summer months (sometimes recurring annually).

Figure 16.10 Scabies infestation in infants often causes vesicopustules on the feet. Sometimes larger blisters are seen, as shown here. The presence of larger blisters on the hands in scabies affecting older children usually represents secondary impetigo.

Figure 16.11 Streptococcal infection in a child with atopic eczema: large blisters with cloudy fluid content.