個案1
個案2
以上兩位患者注射類固醇後3個月痊癒，一年多後都沒有番發。
討論：
斑禿，俗稱「鬼剃頭」，是一種常見的自身免疫性疾病。患者在數星期至數月內，頭部部分頭髮會迅速脫落，而脫髮區域的頭皮通常看似正常，沒有紅腫、痕癢或疼痛。
其成因是免疫系統出現錯誤，T細胞錯誤攻擊毛囊，導致毛髮脫落。約有10至20％患者有家族病史。兒童及年輕人較常見，但任何年齡層都可能發病。此病屬於慢性器官特異性自身免疫疾病，除了毛囊，指甲也可能受影響。
在毛囊層面，病變主要發生於生長期（anagen），隨後迅速轉化為退化期（catagen）及休止期（telogen），最後進入營養不良的生長期（dystrophic anagen）。在疾病活躍期，毛囊無法進入正常的生長階段，因此頭髮無法正常生長。臨床上可見「驚嘆號毛」（exclamation mark hairs）。
分類：
- Alopecia areata (斑禿)：部分頭髮脫落
- AA totalis：全頭頭髮完全脫落
- AA universalis：全身毛髮完全脫落
- Ophiasis：頭髮邊緣範圍脫落
指甲表現： 可見甲板細小凹陷（如錘打黃銅）、半月區斑駁、粗糙甲（trachyonychia）、甚至甲脫落（onychomadesis）。
檢查： 需排除其他疾病，包括系統性紅斑狼瘡（ANA）、二期梅毒（PRP test）、頭癬（tinea capitis）。
治療：
- 外用類固醇藥膏
- 無效時可考慮頭皮內注射類固醇
- 嚴重病例可使用口服類固醇或環孢素（Cyclosporin）
- 光化學療法（PUVA）
- 部分皮膚科醫生會嘗試誘導過敏性接觸性皮炎以刺激毛囊再生
Discussion:
Alopecia areata, commonly known as “patchy baldness,” is a chronic, organ-specific autoimmune disease. Patients experience rapid hair loss over weeks to months, often with normal-appearing scalp skin—no itching or pain.
The pathogenesis involves T-cell mediated immune attack on hair follicles. About 10–20% of patients have a family history. It is more common in children and young adults but can occur at any age. The disease may also affect nails, showing fine pitting, mottled lunula, trachyonychia, or even onychomadesis.
Pathophysiology: Hair follicle damage occurs during the anagen phase, followed by premature transition to catagen and telogen, then to dystrophic anagen. During active disease, follicles fail to progress beyond early anagen, preventing normal hair growth. A clinical hallmark is the presence of “exclamation mark” hairs.
Classification:
- Alopecia areata: patchy hair loss
- AA totalis: complete scalp hair loss
- AA universalis: complete body hair loss
- Ophiasis: band-like hair loss along scalp margins
Investigations: Important to rule out systemic lupus erythematosus (ANA), secondary syphilis (PRP test), and tinea capitis.
Treatment options:
- Topical corticosteroids
- Intralesional corticosteroid injections if topical therapy fails
- Oral corticosteroids or cyclosporin for severe cases
- PUVA photochemotherapy
- Induction of allergic contact dermatitis (used experimentally by dermatologists to stimulate regrowth)