Which condition is described by a fir-tree pattern of lesions on the trunk in a child?

Which condition is described by a fir-tree pattern of lesions on the trunk in a child?

• A. Psoriasis
• B. Eczema
• C. Pityriasis alba
• D. Pityriasis rosea

Answer: (D)

A fir-tree (Christmas-tree) pattern of scaling lesions along the trunk is a hallmark of pityriasis rosea. This condition typically begins with a herald patch, then a few days to weeks later develops multiple smaller oval patches that align along the skin’s tension lines on the trunk, creating a diagonal, tree-like distribution. This distinctive trunk pattern helps distinguish it from other common pediatric dermatoses. Pityriasis rosea is usually self-limited, resolving over several weeks. Management is supportive—reassurance, and symptomatic relief for itch with moisturizers or non-sedating antihistamines, reserving topical corticosteroids for significant pruritus. If a patient has psoriasis, the plaques are generally thick, well-demarcated with silvery scales and commonly affect extensor surfaces, scalp, nails—not the trunk-following pattern seen here. Eczema presents with itchy, red, weeping or crusted patches often in flexures, not the classic trunk-wide fir-tree distribution. Pityriasis alba shows hypopigmented, fine-scaling patches mainly on the face, not the trunk pattern described. Therefore pityriasis rosea best fits the scenario.

A fir-tree (Christmas-tree) pattern of scaling lesions along the trunk is a hallmark of pityriasis rosea. This condition typically begins with a herald patch, then a few days to weeks later develops multiple smaller oval patches that align along the skin’s tension lines on the trunk, creating a diagonal, tree-like distribution. This distinctive trunk pattern helps distinguish it from other common pediatric dermatoses.

Pityriasis rosea is usually self-limited, resolving over several weeks. Management is supportive—reassurance, and symptomatic relief for itch with moisturizers or non-sedating antihistamines, reserving topical corticosteroids for significant pruritus.

If a patient has psoriasis, the plaques are generally thick, well-demarcated with silvery scales and commonly affect extensor surfaces, scalp, nails—not the trunk-following pattern seen here. Eczema presents with itchy, red, weeping or crusted patches often in flexures, not the classic trunk-wide fir-tree distribution. Pityriasis alba shows hypopigmented, fine-scaling patches mainly on the face, not the trunk pattern described. Therefore pityriasis rosea best fits the scenario.