Table I.

Differentiation of PP from CARP5, 6, 7, 8, 9

	Demographic	Clinical morphology	Symptoms	Histology	Treatment	Prognosis
PP	Most common in Asian patients and dark-skinned races; rare in whites	Acute: papular, vesicular, or urticarial erythematous eruption with reticulated appearance on chest and back Chronic: reticulated hyperpigmentation	Severe pruritus ± burning sensation in acute stage	Acute: acute or subacute spongiosis with dyskeratosis ± subcorneal or intraepidermal pustules Chronic: pigment incontinence and sparse dermal lymphocytic infiltrate	Minocycline, doxycycline, tetracycline, dapsone, topical steroids	Acute findings of pruritus and papular or vesicular lesions resolve with treatment; hyperpigmentation persists for months to years
CARP	Occurs in all ethnicities including whites	Scaly, hyperpigmented papules with central confluence and peripheral reticulation on the chest, back, neck, axillae, and occasionally proximal extremities	Asymptomatic in majority; when present, pruritus is mild	Hyperkeratosis, papillomatosis, basilar hyperpigmentation, follicular plugging, flattening of rete ridges	Minocycline, doxycycline, azithromycin, erythromycin, isotretinoin, topical tretinoin, tazarotene, topical steroids	Chronic course with frequent recurrence after discontinuation of therapy; no persistent dyspigmentation

CARP, Confluent and reticulated papillomatosis; PP, prurigo pigmentosa.