Lichen Planopilaris with Pustules: A Diagnostic Challenge

Abstract

Introduction: Lichen planopilaris (LPP) is a lymphocytic primary cicatricial alopecia presenting with scarring hair loss and variable degrees of perifollicular erythema and scaling. Pustules are infrequent and may mimic folliculitis decalvans (FD) and other forms of neutrophilic alopecia. We present a series of LPP cases with pustules and discuss the importance of differentiating them from primary neutrophilic folliculitis. Materials and Methods: Demographic, clinical, histopathological, and follow-up data of 13 cases of LPP with pustules followed at the Department of Dermatology of the University of São Paulo Medical School were described. Results: Seven females and 6 males were included. Onset of signs and symptoms ranged from 23 to 61 years of age. Previous diagnoses were FD in 3 patients, pityriasis amiantacea in 2 cases, and folliculitis keloidalis nuchae in 1 case. Other 7 cases presented typical clinical features of LPP. Discussion: There is limited data concerning LPP with pustules. Our analysis shows that LPP should be considered a differential diagnosis in patients with refractory folliculitis. Cautious examination of the entire scalp with dermoscopy and/or reevaluation after a course of antibiotics can avoid misdiagnosis. Further studies are required to establish the etiology of pustules in the setting of LPP.

Folliculitis decalvans and lichen planopilaris phenotypic spectrum: case report of two paediatric cases

“…7 The significant association with other autoimmune disorders reflects the common susceptibility genes identified in vitiligo and psoriasis, with allelic variations in key genes related to the immune response, such as autoimmune susceptibility 1 (AIS1; PSOR7). 8 While an association of atopy with vitiligo has been reported, 9 this was not observed in our cohort of patients with both psoriasis and vitiligo, suggesting that patients with vitiligo and psoriasis are more prone to a combination of a Th17-and Th1-skewed immune response. In the majority of our…”

“…Nevertheless, as occurred in these cases, they can show concomitant clinical and histopathological features. 6,9 Tufting, pustules and yellow crusts are clinically characteristic of FD, whereas perifollicular cast and erythema suggest LPP. 5,9,10 Regarding histopathology, the identification of multicompound follicular structures, atrophy of the follicular epithelium and prominent plasma cell component instead of the predominance of neutrophils should be considered for the diagnosis of FDLPPPS.…”

“…6,9 Tufting, pustules and yellow crusts are clinically characteristic of FD, whereas perifollicular cast and erythema suggest LPP. 5,9,10 Regarding histopathology, the identification of multicompound follicular structures, atrophy of the follicular epithelium and prominent plasma cell component instead of the predominance of neutrophils should be considered for the diagnosis of FDLPPPS. 5 Further investigations to clarify whether FDLPPPS in fact represents an overlap of both diseases or a late lesion of FD with features simulating LPP are necessary.…”

Eosinophilic folliculitis of the scalp associated with PD‐1/PDL1 inhibitors

“…Morais et al reported 13 cases of LPP presenting with pustules in patients not receiving any anticancer treatments, but even if the clinical aspect is quite similar, in this case histopathology is different for the lack, of a lichenoid infiltrate 4 …”

Folliculitis decalvans and lichen planopilaris phenotypic spectrum: a case series of biphasic clinical presentation and theories on pathogenesis

“…There is very little comment about this relatively common biphasic presentation in the literature. A recently published case series highlighted the diagnostic challenges surrounding the presence of pustules in the setting of LPP . In that study, patients previously diagnosed with LPP, FD, pityriasis amiantacea or folliculitis keloidalis nuchae were ultimately assigned the diagnosis of ‘LPP with pustules’ based on the evolution of the phenotype over time.…”