Granulomatous Dermatitis - An Overview

Introduction

Interstitial granulomatous dermatitis is associated with systemic lupus erythematosus (SLE; an autoimmune disorder). It was initially described as a skin lesion more commonly seen in patients with rheumatoid arthritis (RA) and other autoimmune diseases (immunity against self). A variety of drug therapies and malignancies are also associated with interstitial granulomatous dermatitis patients with or without autoimmune diseases.

What Is Granulomatous Dermatitis?

Granulomatous dermatitis describes various disorders that are characterized by their histological appearance.

• Interstitial granulomatous dermatitis.

• Palisading neutrophilic granulomatous dermatitis.

• Interstitial granulomatous drug reactions.

What Is Interstitial Granulomatous Dermatitis?

Interstitial granulomatous dermatitis is a rare type of skin disorder in which particular patterns of granulomatous inflammation (granulomas are tiny clusters of white blood cells and other tissues) are formed. The original clinical description of the interstitial granulomatous dermatitis is linear erythematous (reddish) palpable cords seen on the lateral (sides) aspects of the trunk, called the rope sign. Several different types of rashes have been described with the same microscopic appearance.

What Are the Clinical Features of Interstitial Granulomatous Dermatitis?

Interstitial granulomatous dermatitis is seen in various types. The clinical features are listed below.

• Red or skin-colored patches, papules, and plaques.

• The lesions are round, oval, or cord-like in shape.

• The lesions may vary in shape and size over days to months.

• Usually symptomless, some patients may have mild itching or burning sensation.

• Lesions tend to be evenly distributed on the trunk, but the limbs also may be affected.

• Commonly affects middle-aged women.

• Most of the affected patients also suffer from autoimmune diseases.

How Is Interstitial Granulomatous Dermatitis Diagnosed?

This interstitial granulomatous dermatitis is diagnosed by pathologists based on a skin biopsy. Characteristic histologic features of interstitial granulomatous dermatitis are the following:

• Few giant cells (large inflammatory cells that form a granuloma).

• Sparse neutrophils and eosinophils (both are types of white blood cells).

• Lymphocytes around the blood vessels.

• Focal degeneration of collagen.

• Dense inflammation on the lower dermis (skin) areas.

How Is Interstitial Granulomatous Dermatitis Similar to Granuloma Annulare?

Granuloma annulare presents with papules (a raised spot on the skin) and plaques (a buildup of papules). Interstitial granulomatous dermatitis and granuloma annulare may appear similar clinically and histologically. However, these are typically formed on the back of the hands or feet. On the other hand, the trunk is more commonly involved in interstitial granulomatous dermatitis. In addition, granulomatous annulare is not closely associated with autoimmune disorders.

Characteristic histologic features of granuloma annulare are:

• Abundant mucin (a protein).

• Rare or absent forms of neutrophils and eosinophils.

• Histiocytes (immune cells in the connective tissue) located in the upper dermis.

What Is Palisading Neutrophilic Granulomatous Dermatitis?

Palisading neutrophilic granulomatous dermatitis is described as crusted papules found on the elbows in patients with RA and eosinophilic granulomatosis with polyangiitis (also called Churg Strauss syndrome, a condition characterized by asthma, high levels of eosinophils, and inflammation of blood vessels). Several other types of rash with the same microscopic appearance involve circular plaques on the trunk region. These lesions are tender and may also ulcerate.

How Is Palisading Neutrophilic Granulomatous Dermatitis Diagnosed?

Palisading neutrophilic granulomatous dermatitis is diagnosed based on the skin biopsy done by the pathologist. The following histologic features of palisading neutrophilic granuloma dermatitis are observed in the biopsy.

• Collagen degeneration.

• Intense neutrophilic granulomatous dermatitis.

• Vasculitis (blood vessel inflammation).

• Interstitial histiocytic infiltrate.

• Variable histological appearance is based on the appearance depending on the eruption stages.

Palisading granulomatous dermatitis has been characterized by degeneration of collagen enveloped by eosinophils that resemble a flame.

What Clinical Relationships Does Granulomatous Dermatitis Have?

Several conditions are associated with interstitial granulomatous dermatitis. However, less information is present about the association with palisading neutrophilic granulomatous dermatitis.

Autoimmune Disease and Conditions: Both forms of granulomatous dermatitis arise in people with other conditions and are considered autoimmune disorders. The complex immune mechanism can be involved in the following conditions.

• Vitiligo (a chronic autoimmune disorder in which skin patches lose color).

• Thyroiditis (inflammation of the thyroid gland).

• Primary antiphospholipid syndromes (an autoimmune disorder that causes increased risk of blood clots).

• SLE.

• Rheumatic and non-rheumatoid arthritis is characterized by symmetrical and involving the fingers, wrists, elbows, and shoulders. These disorders are most commonly associated with arthritis (inflamed joints) that may occur years after the onset of the skin lesions.

Malignancy: Some reports are associated with malignancy in the case of interstitial granulomatous dermatitis. In the case of lung cancer, the lesions clear after cancer treatment. However, there is a rare association with leukemia (blood cancer), lymphoma (cancer of the lymphatic system), squamous cell carcinoma (a skin cancer), and endometrial cancer (a form of uterine cancer).

How Is Granulomatous Dermatitis Treated?

Granulomatous dermatitis typically flares and remits. Successful treatments include the following:

• Hydroxychloroquine- It is an antimalarial drug used in this condition. Patients after regular use experience successful remission of the lesions.

• Steroids- Steroids (topical or systemic form) are useful in the treatment of granulomatous dermatitis.

• Dapsone- It is an immunosuppressant used alone or in combination with steroids in oral form.

What Are Interstitial Granulomatous Drug Reactions?

Interstitial granulomatous dermatitis induced by some medications (calcium channel blockers, beta-blockers, antidepressants, and anticonvulsants) is called interstitial granulomatous drug reactions. It presents as plaques on the trunk, arms, thighs, and skin folds. The rash resolves when the patient withdraws the responsible drug.

How Is Interstitial Granulomatous Drug Reaction Diagnosed?

This interstitial drug reaction may be diagnosed through a skin biopsy. The characteristic histologic feature may show the following listed below:

• Absence of neutrophils.

• Changes within the eosinophils.

• In some cases, palisaded granulomatous changes are associated with collagen necrosis.

Conclusion

A collection of reactive dermatologic conditions known as granulomatous dermatitis is distinguished by distinctive histological patterns, clinical symptoms, and related diseases. Interstitial granulomatous dermatitis has highly reproducing clinical and histologic features. It can also be present with an underlying autoimmune disorder.