Pustular bacterid: causes, symptoms, diagnosis, and treatment

Pustular bacterid is eruption caused by allergic reactions against bacterial focal infection and is characterized by palmoplantar symmetric clustered blisters and pustules, but bacteria are absent in blister fluids.


Causes

It is thought that pustular bacterid may be an independent disease associated with focal infection.


Signs and Symptoms

Blisters occur initially, developing quickly into pustules, sometimes with petechiae between pustules. Skin lesions usually occur in the center of palm or sole, gradually spreading to the entire palm or sole, even borders. Skin lesions occur at the tip of digits or ankles, but interdigital area and toe webs are not involved. Initial skin lesions are often unilateral, and gradually spread to the opposite side, but initial bilateral symmetric skin lesions are present as well. Skin lesions occur in groups and are often consistent, with obvious desquamation while subsiding, with dried and hard scales adhered to the skin surface, with subjective pruritus and pain. Pustular bacterid is a chronic disease, often with repeated relapses. Total count of white blood cells and neutrophils is increased in the onset.


Histopathology

Unilocular pustules in the lower epidermis are present. Little inflammatory infiltration around the pustules is visible. The epidermis on the top of pustules is slightly thickened, but the epidermis between the pustules is basically normal. The pustules contain numerous neutrophils and a small amount of degenerated epidermal cells. Neutrophil infiltration in pustules and around pustules in the upper dermis is visible.


Diagnosis

Diagnostic considerations include:

  • Chronic intractable pustules, often symmetric in the palms and soles
  • Direct relation to focal infections, skin lesions regression after focal infections are cured
  • Increased leukocytes, especially at the onset
  • Positive results of staphylococcus and streptococcus in skin allergic reaction tests
  • Unilocular pustules in the lower epidermis
  • Negative results in bacterial culture of pustule fluids
  • Effective antibiotic treatment

Differential diagnosis

Acrodermatitis continua often occurs after minor trauma, unilaterally, often in the fingertips, with nail infection.

Pustular psoriasis is with typical psoriasis lesions in the elbow, knee or other areas. Pathological changes are the same as psoriasis vulgaris except for large Munro abscesses.

Tinea manus and tinea pedis are with skin lesions often in the interdigital area and toe webs, and fungi can be found in microscopy.


Treatment

Focal infections should be treated.

Systemic antibiotics and topical wet compress with 0.1% ethacridine solution or 1% neomycin solution can be used.