From:  Pathogenesis and management of atopic dermatitis: insights into epidermal barrier dysfunction and immune mechanisms
 

Clinical variants of dermatitis that resemble atopic dermatitis (AD) and their differential diagnostic criteria [12]

Name of variant of dermatitisDescriptionDifferential diagnostic criteria/Associated factors to distinguish it from AD
i. Prurigo nodularis (PN)PN is characterized by intensely itchy, firm nodules that appear on the extremities, particularly the arms and legs. These nodules are often excoriated and can lead to significant skin thickening and scarring.Associated with infections, diabetes mellitus, chronic kidney disease, psychiatric disorders, and neuropathic disorders.
ii. Nummular (Discoid) dermatitisNummular dermatitis is marked by coin-shaped, itchy, and scaly patches on the skin. The lesions are typically well-defined and may appear on the arms, legs, and torso.

Distinguished by well-defined round lesions; more commonly linked to dry skin or contact dermatitis.

  • Xerotic lesions (dry patches/lesions on skin)

  • Tinea corporis (a scaly ring-shaped area, on the buttocks, trunk, arms, and legs)

  • Allergic contact dermatitis (itchy rash)

  • Psoriasis (scales and dry patches)

  • Mycosis fungoides (cutaneous T-cell lymphoma)

iii. Lichenoid dermatitisThis type presents with lichenoid (scaly, purple) plaques that resemble lichen planus. The lesions are typically flat-topped and can be itchy.Differentiated by its lichen-like appearance or lichenification of the skin and mucous membranes and association with drugs or systemic diseases.
iv. Follicular dermatitisCharacterized by inflammation around hair follicles, leading to papules or pustules. It often affects areas with dense hair follicles, like the scalp or back.

Distinguished by follicular involvement and less likely to have the widespread pruritus typical of AD.

  • Lichen spinulosus (follicular papules)

  • Lichen nitidus (red-brown papules; hemorrhagic)

  • Keratosis pilaris (rough patches acne like appearances)

  • Phrynoderma (follicular hyperkeratosis; vitamin A deficiency)

  • Pityriasis rubra pilaris (reddish-orange scaling plaques)

v. Dyshidrosis or pompholyxDyshidrosis is marked by small, itchy, fluid-filled blisters on the skin. The blisters can be painful and may lead to peeling and scaling.

Characterized by vesicular eruptions on palms and soles, often associated with sweating or stress.

  • Contact dermatitis

  • Herpes simplex (blisters/ulcers)

  • Bullous disorders (large fluid-filled blisters)

  • Adverse drug reactions

  • Pustular psoriasis (pus-filled blisters on plaques)

  • Scabies (intense itchy condition)

vi. ErythrodermicThis severe form of dermatitis involves widespread inflammation and exfoliation of the skin, covering large areas of the body. It can cause redness, scaling, and severe itching.Characterized by extensive involvement of the skin, differing from AD by its severe presentation and systemic involvement.
Return to article view