Tinea imbricata in Adult
Lesions begin as small, brown, pruritic macules and papules and progress to concentric rings of scales. The infection usually begins in childhood, and progresses slowly over time. Over 75% of those affected will have lesions covering 50% or more of their skin surface. The lesions are quite pruritic, and the pruritus is aggravated by heat. Areas of lichenification develop after chronic excoriation. As this infection is superficial, patients do not have accompanying constitutional symptoms.
Risk factors include sharing an ancestry with endemic populations (travelers do not seem to develop this condition even after long stays and close contact), low socioeconomic class, and poor hygiene. Females are more commonly affected in the adult population; this sex ratio is reversed in children. Environmental exposures have not been linked to infection. A T-cell defect caused by an autosomal recessive trait has been suggested, but not proven.
B35.5 – Tinea imbricata
240699006 – Tinea imbricata
Differential Diagnosis & Pitfalls
- The scale on the lesions of is finer, and removal of the scale results in pinpoint bleeding (Auspitz sign).
- The plaques of are smaller and do not have rings of scale.
- – Digitate dermatosis lesions are more linear and follow lines of cleavage.
- Tinea indecisiva (tinea pseudoimbricata) – that mimics tinea imbricata. These cases are not caused by Trichophyton concentricum but rather by other Trichophyton or Microsporum species. There is usually underlying immunosuppression in patients with tinea indecisiva.