Sir,

Fahr’s syndrome is defined by the presence of bilateral symmetrical intracerebral calcifications located in the basal ganglia. We report a case of diffuse pustulosis associated with Hashimoto’s thyroiditis revealing Fahr’s syndrome.

A 72-year-old female with a history of anxiety and depression for 2 years, no notion of new drug administration or skin psoriasis, was admitted to our department for a diffuse pustular eruption evolving for 1 week. Her history included not exploited paroxysmal paresthesia of the lips and hands evolving for 1year.

On admission the patient was febrile 38.6° and confused, her general condition was altered. Dermatological examination revealed erythematous plaques bordered by non-follicular pustules predominantly on the folds, neck, abdomen and thighs (Fig. 1). The sub mammary folds were macerated, and there were areas of epidermal detachment on the thighs, lower back and breasts. Mucosal examination showed oral thrush, bilateral blepharitis and healthy genital mucosa. Several diagnoses were suggested: pustular psoriasis, pustulosis due to hypocalcemia, acute generalized exanthematous pustulosis, IgA pemphigus and Sneddon’s subcorneal pustulosis.

Figure 1: Erythematous plaques with millicellular crusts, bordered by non-follicular pustules.

The microbiological examination of the pus was sterile. Laboratory analyses revealed leukocytosis with neutrophilia, profound hypocalcemia at (29 mg/L), hyperphosphatemia at (108 mg/l), parathormone at (1 pg/mL), vitamine D at (14.7ng/ml). The TSH was 4.66 mIU/l and the anti TPO antibodies were 16.4. A cervical ultrasound was performed and found EU-TIRADS 2 and 3 thyroid nodules. In addition to the work-up, a Computed Tomography brain CT scan was performed, showing bilateral and symmetrical calcifications of the basal ganglia (Figs. 2a and 2b). The final diagnosis of Fahr’s syndrome with hypoparathyroidism associated with Hashimoto’s thyroiditis was made.

Figure 2: (a and b) CT scan showing bilateral and symmetrical calcifications of lenticular nuclei.

The patient was put on rehydration with saline and a calcium and potassium infusion, calcium 2g/d associated with 1-alpha-hydroxy-vitamin D3 1ug/day. The evolution was favorable with correction of the hypocalcemia, complete healing of the pustulosis and disappearance of the paresthesia. The patient is currently undergoing biannual follow-up cervical ultrasound. The brain CT scan was not repeated.

Fahr syndrome is a rare condition characterized by clinical polymorphism with a predominance of neuropsychiatric manifestations and disorders of phosphocalcic metabolism. The dermatological manifestations are numerous, the main clinical feature is generalized pustulosis as reported in our case. We may also find: dry scaly skin, eczematous eruptions, hyperkeratotic maculo-papular eruptions, generalized myxedema or cutaneous mucinosis, erythema annulare centrifugum, exfoliative erythroderma. The hairs are coarse and fall off, the nails are thin and frail [1]. The neurological manifestations are polymorphous and non-specific, they include seizures, delirium or confusion, movement disorder as seen in our case, personality disorder or changes, mood disorder and anxiety or an obsessive behavior [2].

The features of this syndrome can be varied and the diagnosis is established by obtaining a CT or Magnetic Resonance Imaging MRI scan of the head, although CT scan is considered more sensitive for finding deposits [3]. Pathological studies show that calcium is the main element present and it accounts for the radiological appearance of the disease. Mucopolysaccharides, remnants of aluminum, cobalt, iron have also been reported [4].

Cutaneous manifestations of Fahr’s syndrome linked to hypoparathyroidism involve the complex inter-relationships between PTH, vitamin D, calcium and phosphorus and their action on the epidermis. The modification of the ionic calcium concentration alters the pattern of proliferation and differentiation in epidermal cells [5]. The hypocalcemia that generates from the hypoparathyroidism explains the majority of the clinical signs, however, the skin rash has been described with hypocalcemia of various etiologies [6]. Apart from hypoparathyroidism Fahr’s syndrome is more rarely seen in pseudo-hypoparathyroidism [7].

To the best of our knowledge Fahr’s syndrome has no current cure to reverse calcifications; it is only about treating the underlying conditions.

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