Monthly Diagnostic Quiz

Clinical Data (Figs. 13.1, 13.2, 13.3, 13.4, 13.5, and 13.6)

• A 4 YO boy, a product of normal pregnancy and consanguineous marriage.
• He presented with erythematous scaly eruption involving the neck, axilla, lower abdomen, and perioral area.
• The eruption started 4 weeks before presentation and it was preceded by upper respiratory tract infection.
• His history revealed the followings:
  • Similar eruptions started at the age of 1 year and had been intermittent, mostly following upper respiratory tract infection.
  • At the age of 3 years, developed recurrent attacks of epilepsy.
  • Alopecia of the scalp started at the age of 2 years. It involved the entire scalp and persisted until the time of presentation.

Biopsy Findings

Non-specific.

Investigations

Lab investigations:

• Common lab tests:
  • CBC: normal CBC.
  • Zinc level: normal (this excluded zinc deficiency).
  • Fatty acid levels: normal (this excluded free fatty acid deficiency).
  • Branched-chain amino acid level: normal (this excluded branched-chain amino acid deficiency).
  • Biotin level: low.
  • Biotinidase level: low (30% of normal level)

Figs. 13.1 – 13.6

Fig. 13.1

Fig. 13.2

Fig. 13.3

Fig. 13.4

Fig. 13.5

Fig. 13.6

What is the diagnosis?