© Angel Fernandez Flores, MD, PhD Chronic actinic dermatitis

 

Chronic actinic dermatitis

 

Aka actinic reticuloid.

 

Concept

An UVR- or visible light-induced eczema.

 

Clinical presentation

Most severe in summer.

Pruritic scaly erythematous eruption in the sun-exposed areas, including head, neck, face and arms.

It can mimick a lymphoma.

Later, thickened lichenified plaques appear.

 

 

Morphology

 

Early stages

Rather non-specific:

Parakeratosis, acanthosis and spongiosis.

 

 

Superficial perivascular inflammatory infiltrate, made of lymphocytes, mainly CD8+, some of them even convoluted.

Scattered eosinophils and plasma cells.

Multinucleated stellate myofibroblasts.

Sometimes multinucleated giant cells related to dermal elastosis.

 

 

Advanced stages

Dense cellular infiltrate in papillary and reticular dermis, even involving the subcutis.

Multinucleate myofibroblasts are common.

 

Main differentials

Other eczemas, Seborrheic dermatitis, Atopic dermatitis: clinical information required.

Mycosis fungoides: atypical lymphocytes; Pautrier´s microabscesses; lymphocytes in a single row in the basal epidermal layer. Most cases are CD4+. Eosinophils and plasma cells are rare

 

 

© Angel Fernandez Flores