Urticaria pigmentosa
Urticaria pigmentosa は、皮膚肥満細胞症の最も一般的な形態です。過剰な肥満細胞が皮膚内に集積することで起こり、刺激を受けると皮膚に蕁麻疹や病変が現れるまれな疾患です。赤や茶色の斑点が、主に胸部、額、背中付近に見られることが多いです。これらの肥満細胞は、皮膚をこすったり熱にさらされたりするとヒスタミンを大量に放出し、アレルギー反応を起こします。その結果、刺激部位に限局した蕁麻疹（「ダリエ徴候」とも呼ばれます）が生じます。
relevance score : -100.0%
ReferencesMastocytosis は、皮膚、骨髄、消化器系など体のさまざまな部位に肥満細胞が過剰に存在する状態です。世界保健機関 (WHO) によると、cutaneous mastocytosis は主に 3 つのタイプに分類されます。最初のタイプ（mastocytomas）は、孤立性または少数（≤3 個）の病変で構成されます。2 番目のタイプ（urticaria pigmentosa）は、複数の病変を伴い、通常は 10 個以上 100 個未満の範囲です。最後のタイプは、皮膚全体に広がる広範な病変を示します。urticaria pigmentosa は小児における皮膚肥満細胞症の最も一般的な形態ですが、成人でも発症することがあります。通常は無害で、思春期に改善することが多いです。成人の肥満細胞症とは異なり、urticaria pigmentosa が内臓に及ぶことはほとんどありません。urticaria pigmentosa の特徴のひとつは、一般に蕁麻疹として知られる、皮膚に小さなかゆみを伴う赤褐色または黄褐色の斑点や病変が現れることです。これらの斑点は主に小児期に出現し、生涯にわたって残ることがあります。
Mastocytosis is a disorder characterized by mast cell accumulation, commonly in the skin, bone marrow, gastrointestinal (GI) tract, liver, spleen, and lymphatic tissues. The World Health Organization (WHO) divides cutaneous mastocytosis into 3 main presentations. The first has solitary or few (≤3) lesions called mastocytomas. The second, urticaria pigmentosa (UP), involves multiple lesions ranging from >10 to <100 lesions. The last presentation involves diffuse cutaneous involvement. UP is the most common cutaneous mastocytosis in children, but it can form in adults as well. It is considered a benign, self-resolving condition that often remits in adolescence. Unlike adult forms of mastocytosis, there is rarely any internal organ involvement in UP. What makes UP particularly distinctive is its tendency to manifest as small, itchy, reddish-brown, or yellowish-brown spots or lesions on the skin, commonly referred to as urticaria or hives. These spots typically appear in childhood and can persist throughout a person's life.
Mastocytosis is a disorder characterized by mast cell accumulation, commonly in the skin, bone marrow, gastrointestinal (GI) tract, liver, spleen, and lymphatic tissues. The World Health Organization (WHO) divides cutaneous mastocytosis into 3 main presentations. The first has solitary or few (≤3) lesions called mastocytomas. The second, urticaria pigmentosa (UP), involves multiple lesions ranging from >10 to <100 lesions. The last presentation involves diffuse cutaneous involvement. UP is the most common cutaneous mastocytosis in children, but it can form in adults as well. It is considered a benign, self-resolving condition that often remits in adolescence. Unlike adult forms of mastocytosis, there is rarely any internal organ involvement in UP. What makes UP particularly distinctive is its tendency to manifest as small, itchy, reddish-brown, or yellowish-brown spots or lesions on the skin, commonly referred to as urticaria or hives. These spots typically appear in childhood and can persist throughout a person's life.
6歳の女の子は、最初に頭皮に黒い斑点がいくつかでき、6か月の間に顔や体へと広がりました。圧迫すると腫れ、赤くなり、かゆみを感じると述べました。顔面紅潮、嘔吐、下痢、喘鳴などの症状はなく、個人・家族歴からも関連する手がかりは得られませんでした。検査の結果、頭皮、額、顔、首に複数の黒い斑点が認められ、胸と背中にはわずかに隆起した黒い斑点がありました。シミを軽くこすると、2分以内に腫れとかゆみが生じ、15〜20分以内に消失しました（Darier's sign）。
A 6-year-old female, presented with multiple dark-colored lesions, which started over the scalp and further progressed to involve the face and trunk since past six months. She gave a history of elevation, redness, and itching on the lesions on application of pressure. There was no associated flushing, vomiting, diarrhoea, or wheeze. The personal and family history was not contributory. On examination, there were multiple hyperpigmented macules over the scalp, forehead, face, and neck in addition to minimally elevated hyperpigmented plaques over the chest and the back. Gentle rubbing of the lesions elicited urtication and itching within 2 min and it resolved within 15–20 minutes, suggestive of the Darier's sign.
A 6-year-old female, presented with multiple dark-colored lesions, which started over the scalp and further progressed to involve the face and trunk since past six months. She gave a history of elevation, redness, and itching on the lesions on application of pressure. There was no associated flushing, vomiting, diarrhoea, or wheeze. The personal and family history was not contributory. On examination, there were multiple hyperpigmented macules over the scalp, forehead, face, and neck in addition to minimally elevated hyperpigmented plaques over the chest and the back. Gentle rubbing of the lesions elicited urtication and itching within 2 min and it resolved within 15–20 minutes, suggestive of the Darier's sign.
