Irritant Contact Dermatitis Workup

Updated: Aug 21, 2019
  • Author: Savina Aneja, MD; Chief Editor: William D James, MD  more...
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Workup

Approach Considerations

No single diagnostic test exists for irritant contact dermatitis (ICD). The diagnosis rests on the exclusion of other cutaneous diseases (especially allergic contact dermatitis) and on the clinical appearance of dermatitis at a site sufficiently exposed to a suspected or known cutaneous irritant. Laboratory studies are generally of little value in proving a diagnosis of contact dermatitis. However, they may be of value in eliminating some disorders from the differential diagnosis.

Findings of significantly elevated serum immunoglobulin E occasionally are useful to substantiate an atopic diathesis in the absence of a personal or family history of atopy.

Go to Allergic Contact Dermatitis, Pediatric Contact Dermatitis, and Protein Contact Dermatitis for complete information on these topics.

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Bacterial and Fungal Studies

A bacterial culture can be obtained and is especially useful in cases complicated by secondary bacterial infection. A potassium hydroxide (KOH) examination of scrapings may be performed and samples for mycology may be obtained to exclude superficial tinea infections or candidal infections, depending on site and morphology of lesions.

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Patch Testing

Patch testing can be performed to diagnose contact allergies, but no patch test exists that proves that a cutaneous irritant is responsible for a particular case of irritant contact dermatitis. Diagnosis rests on exclusion of allergic contact dermatitis and history of sufficient exposure to a cutaneous irritant.

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Skin Biopsy

Skin biopsy can help exclude other disorders, such as tinea, psoriasis, or cutaneous T-cell lymphoma.

Skin biopsy of skin lesions of the palms and soles has several potential pitfalls. The stratum corneum and epidermis are particularly thick there, which makes the histologic diagnosis of psoriasis more difficult and increases the possibility that the specimen lacks sufficient dermis for optimal diagnosis. In the thenar area, an overly deep biopsy can cut the recurrent branch of the median nerve. A biopsy from the sole may leave a chronic painful scar on which the patient must walk.

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Direct Microscopy

Skin scrapings of cutaneous lesions may help exclude scabies or may reveal fiberglass fibers as a cause of a patient's pruritus. To asses for scabies, superficial epidermal cells can be scraped lightly from the skin surface with a No. 15 blade. Skin scrapings can be evaluated with light microscopy on a glass slide containing mineral oil.

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Histologic Findings

The histopathology of acute experimental irritant contact dermatitis (ICD) has been studied to a greater extent than chronic irritant contact dermatitis, which is the primary clinical complaint. Cellular changes seen in the skin vary according to the chemical nature and concentration of the irritant applied, duration of exposure, severity of ensuing response, and time of sampling for acute irritant contact dermatitis. Many primary irritants cause overt necrosis if applied in a sufficiently high concentration for sufficient time.

Most histologic examinations of irritant contact dermatitis reveal some degree of intercellular edema or spongiosis in the epidermis. Spongiosis usually is less pronounced than that seen in allergic contact dermatitis reactions.

Parakeratosis also is observed widely in irritant contact dermatitis reactions.

The histology of chronic irritant contact dermatitis is one of hyperkeratosis with areas of parakeratosis, moderate-to-marked epidermal hyperplasia (acanthosis), and elongation of the rete ridges.

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