Confluent and reticulated papillomatosis associated with hyperthyroidism

ARTICLE

Auteur(s) : Chun-Hong Zhang¹, Caiping Zhang², Jianbing Wu², Shi-Jun Shan³, Quan-Zhong Liu³, Zhiyi Fu³, Ying Guo⁴, Huachen Wei⁵, Hong-Duo Chen⁶

¹Department of Dermatology, The Second Hospital of Shandong University; Jinan, China
²Institute of Dermatology, Chinese Academy of Medical Sciences, Peking Union Medical College, Nanjing, China
³Department of Dermatology, Tianjin Medical University General Hospital, 154 Anshan Road, Tianjin 300052, China
⁴Ackerman Academy of Dermatopathology, New York, USA
⁵Department of Dermatology, Mount Sinai Medical Center, New York, USA
⁶Department of Dermatology, No.1 Hospital China Medical University, Shenyang, China

A 19-year-old Chinese female presented with reticular brownish papules on her neck and trunk for about 2 months. The patient complained of palpitations, irritability and tremor of the hands which had started 6 months previously, but the symptoms were mild. Hyperthyroidism was diagnosed, without medication prescribed. Several brownish reticular papules developed on her intermammary and interscapular areas; the lesions gradually increased in number and the neck, chest and back were subsequently involved. There was no history of any other disease or drug intake. The family history was unremarkable.

At presentation, the symptoms of hyperthyroidism were severe; weight loss (body mass index 18.4; normal value 18.5 ~ 22.9) and ophthalmoptosis were observed. A heart rate of 107 beats per minute, evagination of eyeballs, tremor of hands and enlarged thyroid gland with enhanced Doppler flow were observed. Skin examination revealed numerous brownish, 1-3 mm, slightly hyperkeratotic papules, coalescing to form a reticulated pattern and distributed widely on the neck, chest and abdomen, especially the intermammary and scapular regions (figure 1A). Mycology examination of lesion scrapings showed negative results. ECG examination exhibited sinus tachycardia. Laboratory tests including blood, urine and stool routine, blood sugar, liver and kidney function were all within normal limits. The thyroid function test showed: TSH 0.03 uIU/mL (0.34 ~ 5.60), FT₃ 15.16 pg/mL (2.5 ~ 3.9), FT₄ 4.71 ng/dL (0.61 ~ 1.22), TPO-Ab 183 IU/mL (< 35), TR-Ab 86.82 U/L (< 14). The 2-hour thyroid iodine uptake rate was 59.5% (4~25%), the 6-hour 88.8% (8~36%) and the 24-hour 94.3% (18 ~ 54%). A skin biopsy from abdominal papules showed hyperkeratosis, epidermal papillomatosis and sparse superficial perivascular lymphocytic infiltrate in the dermis (figure 1C); a diagnosis of confluent and reticulated papillomatosis (CARP) was made.

Propylthiouracil (PTU)was prescribed, 300 mg daily, for hyperthyreosis and propranolol, to lower the heart rate. Neither local nor systemic treatment was given to skin lesions because they were asymptomatic. After 2 weeks treatment, skin lesions cleared completely accompanied with marked improvement of the hyperthyroidism symptoms. At the 1-month follow-up visit, some brownish papules recurred (figure 1B) following arbitrary discontinuation of treatment. Thyroid function tests changed to TSH 0.28 uIU/mL, FT₃ 5.6 pg/mL, FT₄ 1.28 ng/dL, TPO-Ab 46.2 IU/mL and TR-Ab 22.10 U/L. PTU therapy was reinitiated with 200 mg daily for one week. The lesions cleared again. After another 4-weeks’ treatment, the hyperthyreosis disappeared and thyroid function returned to normal. PTU was decreased to maintenance therapy for another 6 months. No relapse of CARP was observed at 1-year follow-up visit after PTU withdrawal.

The etiology and pathogenesis of CARP remain unclear. Proposed causative factors include a keratinization disease, Pityrosporum, bacterial and Dietzia infection, genetic susceptibility and endocrinopathy [1, 2]. Familial cases and coincidence with Greither's disease of CARP have been described; which support the hypothesis of keratinization alterations and genetic susceptibility [3, 4]. Hirokawa et al. [5] reported CARP with acanthosis nigricans in an obese patient with abnormal glucose tolerance and hyperinsulinemia. To the best of our knowledge, there were no previous reports about CARP with hyperthyroidism, which may be associated with pretibial myxedema, hair loss and onycholysis [6]. In our case, with improvement of the hyperthyreosis and thyroid functions, the CARP lesions cleared completely with PTU therapy.

Numerous agents have been used to treat CARP [1]. In our case, with improvement of hyperthyreosis after PTU therapy, the CARP lesions cleared completely. It is unclear whether the change in thyroid hormone levels resulting from PTU, or PTU itself was responsible for the effect. But it suggests that hyperthyroidism could be an important pathogenetic factor in CARP. Further studies are needed to elucidate the mechanism of this phenomenon.Disclosure. Financial support: none. Conflict of interest: none.

References

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