Skin

1] A 25-year-old man presents with recurrent episodes of flexural eczema, contact urticaria, recurrent skin infections and severe abdominal cramps and diarrhea upon taking sea foods. He is suffering from:

Atopic dermatitis It is a part component of atopic diathesis and is characterized by lowered threshold to pruritus. It may arbitrarily be divided into infantile, childhood/adolescent and adult variants.

In infants it usually appears about the third months of life. The child is usually fair, fat, anxious, with shiny eyes and glassy expression. The face, particularly the cheeks are the usually affected site. The lesions are erythematous and dry or mildly oozing. It is characterized by remission and relapses. However, it usually disappears at the age of 2 years. In a high proportion of patients, the condition recurs in late childhood, adolescence or early adult life. At this time, dermatitis tends to localize in the flexural areas, the antecubital and popliteal fossae, neck, eyelids, and behind the ears. At times the eruption may become generalized. The features are essentially of erythema, edema, vesiculation, and oozing. In the adult phase, the skin may be lichenified.

2] A 5 year old male child has multiple hyper pigmented macules over the trunk. On rubbing the lesion with the rounded end of a pen. he developed urticarial wheal, confined to the border of the lesion. The most likely diagnosis is:

FIXED DRUG REACTIONS These reactions are characterized by one or more sharply demarcated, erythematous lesions in which hyper pigmentation results after resolution of the acute inflammation; with rechallenge, the lesion recurs in the same (i.e., "fixed") location. Lesions often involve the lips, hands, legs, face, genitalia, and oral mucosa and cause burning. Most patients have multiple lesions. Patch testing is useful to establish the etiology. Fixed drug eruptions have been associated with phenolphthalein, sulfonamides, tetracyclines, phenylbutazone, NSAIDs, and barbiturates. Although cross-sensitivity appears to occur between different tetracycline compounds, cross-sensitivity was not elicited when different sulfonamide compounds were administered to patients as part of provocation testing.

3] A 30 year old male had severely itchy papulo-vesicular lesions on extremities, knees, elbows and buttocks for one year. Direct immunofluorescence staining of the lesions showed IgA deposition at dermo epidermal junction. The most probable diagnosis is:

Dermatitis herpetiformis (DH) is a chronic, pruritic, papulovesicular eruption, symmetric in distribution, with a predilection to involve the extensor of the extremities, shoulders, and buttocks. Involvement of the mucosae is infrequent. It usually affects the young men and women. Remission and relapses mark the chronic course of the disease. Gluten sensitive enteropathy is its accompaniment. HLA-B8 may be an additional indicator.

The precise etiology is debatable; however, it is presumed that dermatitis herpetiformis represents an allergic state in which the antigen is being presented to a genetically predisposed host via the gastrointestinal tract. The predisposition is through the HLA-B8 linkage. The antigen evokes an immune response producing gastrointestinal lesions and stimulating IgA .antibody production. The antigen-antibody complexes, so formed, gain entrance into the systemic circulation, and are deposited in the skin. The IgA-immune complexes activate the alternative complement pathway, generating the inflammatory process resulting in lesions of dermatitis herpetiformis.