Section 1 -
Clifton R. White, Jr.
Professor of Dermatology and Pathology
Oregon Health and Sciences University
Psoriasiform Dermatitis Case Histories
A 36-year old women presented for a generalized eruption on the central abdomen. The clinician considered psoriasis versus pityriasis lichenoides et varioliformis acuta.
Case 1 - Slide 1
A 62-year old man presented for a generalized pruritic plaque-like eruption. The biopsy was taken from his left upper back where the clinician considered nummular dermatitis, mycosis fungoides, and sarcoidosis.
Case 2 - Slide 1
A 52-year old women presented with erythroderma (total body erythema). In addition, she had discrete papules in some areas. Several biopsies were taken.
Case 3 - Slide 1
A 44-year old man developed a whitish change at both the left and right oral comissure.
Case 4 - Slide 1
A 44-year old woman presented for a pruritic eruption. A biopsy from her left arm was submitted to rule out folliculitis versus eczema versus ?
Case 5 - Slide 1
A 42-year old woman developed multiple pruritic nodules. A biopsy was taken from the left upper back where the clinician considered excoriated prurigo nodule, lichen simplex chronicus, or deep fungal infection.
Case 6 - Slide 1
A 5-year old boy presented with a two year history of increasing pigmentation of a plaque on his right thigh extending to his knee.
Case 7 - Slide 1
I: Psoriasiform Only
II: Psoriasiform Lichenoid
- Allergic contact dermatitis
- Nummular dermatitis
- Dyshidrotic dermatitis, late
- Pityriasis rubra pilaris
- Seborrheic dermatitis
- Lichen simplex chronicus/
- Prurigo nodularis/
- Acanthoma fissuratum/
- Pressure papule from prosthesis/
- Surfer's nodules
- Chondrodermatitis nodularis chronica helicis
- Lichen striatus
- Mycosis fungoides, plaque
- Inflammatory linear verrucous epidermal nevus
- Syphilis, secondary
Applying a pattern approach and algorithmic method for diagnosing inflammatory skin
diseases has numerous advantages over other, less structured diagnostic methods. Inflammation in the
skin can usually, at scanning power (2.5x), be easily categorized into one of nine patterns, the most
common and extensive of which is superficial perivascular dermatitis in which inflammatory cells are
present around the superficial dermal vascular plexus. In utilizing Ackerman's algorithmic approach, at
certain points, key questions should be asked in order to determine the next appropriate branch in the
outline to follow. For example, if one is confronted by a superficial perivascular infiltrate, the next
key question is: ARE THERE EPIDERMAL CHANGES? A number of superficial perivascular dermatitides have
no epidermal changes, such as tinea versicolor, Schamberg's disease, and
urticaria. If epidermal changes are present, the next key question is: WHICH
OF FOUR POSSIBLE EPIDERMAL CHANGES ARE PRESENT: INTERFACE, BALLOONING, SPONGIOTIC, OR PSORIASIFORM?
Interface dermatitides are those in which there is alteration along the dermal epidermal junction, or
interface, such as erythema multiforme or lichen planus. Ballooning
dermatitides are characterized by intracellular edema within keratinocytes such as viral infections, fixed drug eruption, etc.
Spongiotic dermatitides are characterized by intracellular edema between keratinocytes and is the largest category in the superficial perivascular
pattern. Finally, psoriasiform dermatitides are characterized by epidermal hyperplasia, and are our
subject for this session. Psoriasiform dermatitides may be subdivided into those diseases which are
psoriasiform only and those accompanied by a lichenoid infiltrate (psoriasiform lichenoid).
Every major division and subdivision in the algorithm, in general, has a prototype which is usually
the most common example of that inflammatory pattern. The prototype for psoriasiform dermatitis, as the
name indicates, is psoriasis.
I. Psoriasiform Only
Allergic Contact Dermatitis / Nummular Dermatitis / Dyshidrotic
- Mounds of parakeratosis containing neutrophils
- Neutrophils in spongiform distribution in the upper
- Diminished granular layer
- Thinning of the suprapapillary plate
- Uniform epidermal hyperplasia
- Anastomoses at the bases of the rete ridges
- Increased numbers of mitoses
- Dilated and tortuous blood vessels in the dermal papillae
- A superficial perivascular lymphocytic infiltrate
Dermatitis, Late (Chronic)
Pityriasis Rubra Pilaris
- Scale crust (plasma, neutrophils, and parakeratosis) or
hyper- and parakeratosis
- Irregular hypergranulosis, irregular epidermal
- A superficial perivascular infiltrate often with a
mixture of eosinophils.
- Parakeratosis alternating with orthokeratosis in both a horizontal and vertical direction
- Occasionally collections of neutrophils within the stratum corneum
- Follicular plugging
- Intact granular layer
- Less epidermal hyperplasia than psoriasis
- A superficial perivascular predominately lymphocytic infiltrate.
Dermatophytosis and Candidiasis
- Irregular epidermal hyperplasia
- Mounds of scale-crust accentuated at the edges of follicular ostia
- Superficial perivascular predominantly lymphocytic infiltrate
Lichen Simplex Chronicus / Prurigo Nodularis / Picker's Nodule / Acanthoma Fissuratum / Pressure Papules from Prostheses / Surfer's Nodules
- Similar changes to those seen in chronic allergic contact
- Often times neutrophils in the stratum corneum which are
a clue to the presence of organisms
Chondrodermatitis Nodularis Chronica Helicis
- Compact hyperkeratosis, parakeratosis, or crust
- Irregular hypergranulosis
- Irregular epidermal hyperplasia
- Prominent fibrosis in the dermal papillae where there are
thickened collagen bundles, mainly arranged perpendicular to the surface
- A superficial perivascular lymphocytic infiltrate often
mixed with eosinophils
II. Psoriasiform Lichenoid
- Prurigo nodule-like features with a central horn-filled
plug or crusted ulceration overlying fibrin deposition
- Features of granulation tissue laterally
- "Chondroid" alteration of the dermis as it merges with
the underlying cartilage
- Analogous to a clavus (corn); no evidence of a
Occasionally, epidermal hyperplasia may be accompanied by a band-like rather than perivascular infiltrate.
Mycosis Fungoides, Plaque
- Small mounds of scale-crust and hyperkeratosis
- Irregular epidermal hyperplasia, often containing some
spongiosis as well
- Dyskeratotic keratinocytes
- A superficial perivascular band-like infiltrate of
lymphocytes which often contains collections of epithelioid histiocytes (granulomatous).
Inflammatory Linear Verrucous Epidermal Nevus (Ilven)
- Hyper- and parakeratosis, sometimes containing
collections of neutrophils
- Fairly regular epidermal hyperplasia with increased
numbers of lymphocytes in all areas of the epidermis (per unit area)
- Band-like infiltrate of lymphocytes in the thickened,
fibrotic, papillary dermis
- Many lymphocytes with folded ("cerebriform"),
hyperchromatic nuclear membranes.
- Alternation of ortho- and parakeratosis in the thickened
- Fairly regular epidermal hyperplasia
- A superficial perivascular predominantly lymphocytic
- Parakeratosis containing neutrophils
- Irregular epidermal hyperplasia also containing
- A superficial to superficial and deep perivascular and
lichenoid infiltrate of lymphocytes, numerous plasma cells, and histiocytes
- Treponemal spirochetes may often be demonstrated with
endothelial cells in the superficial dermis as well as within epidermal keratinocytes (Warthin-Starry,