The differential includes syphilis and exfoliative dermatitis
The differential diagnosis includes various forms of psoriasiform dermatitis, such as secondary syphilis, chronic spongiotic dermatitis, psoriasiform drug eruption, exfoliative dermatitis, and pityriasis rubra pilaris. A combination of clinical and histopathologic findings is used to zero in on the diagnosis. The summary below highlights the clinical findings.
Secondary syphilis manifests with symmetric papular eruptions primarily on the trunk and extremities with involvement on the palms and soles. Lesions are red or reddish brown, can be smooth, and are rarely pustular.
Chronic spongiotic dermatitis manifests with a shiny, glazed, cracked appearance and itchy reddish lesions on the soles.
Psoriasiform drug eruption manifests after drug administration with a psoriasis-like rash with erythematous, squamous, thick, dry, and plaque-type lesions.
Exfoliative dermatitis manifests with erythematous single or multiple pruritic patches on the trunk, head, and genitals.
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