Harbert T, Sarma D. (2011). An erythematous folliculocentric papular lesion on the chest of a 60-year-old man: What is your diagnosis? J Dermatol Case Rep. J Dermatol Case Rep. 2011 Sep 21;5(3):56-7. PMID 22187582 PubMED.

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An erythematous folliculocentric papular lesion on the chest of a 60yearold man: What is your diagnosis?

 Tracey Harbert 1 and Deba P Sarma 2

 Department of Pathology, Creighton University Medical Center, Omaha, NE,

  1. Department of Pathology, Lakeside Hospital, Omaha, NE,

Corresponding  author:

Deba P Sarma, MD, Department of Pathology, Lakeside Hospital, Omaha, NE 68130. E-mail: dpsarma@gmail.com



Folliculitis has many etiologies including bacterial, fungal, viral and parasitic. Therefore, an accurate determination of the cause is necessary to direct treatment.   This is a case of a 60-year-old man who presented with an erythematous papule     on his chest. Biopsy showed granulomatous inflammation,  abscess  formation,  and  the  causative  agent  was  Demodex. (J  Dermatol  Case  Rep. 2011; 5(3): 56-57)

Key words:

demodex, folliculitis, histopathology

Folliculitis presents as single or multiple erythematous pa- pules, pustules, ulcerations, or blisters on hair bearing skin. There are multiple etiologies including bacteria, viruses, fun- gi, and parasites. Host risk factors include age and immu- nosuppresion. Skin breakage is often a predisposing factor, although some cases may originate due to bacterial over- growth in intact skin, particularly in immunocompromised hosts. Because of the wide variety of etiologies, accurate identification is needed to appropriately treat the cause.

Case Report

A 60-year-old man presented with an erythematous pa- pule on his chest. He did not have any evidence of immu- nosuppression. A punch biopsy was obtained. Sections sta- ined with hematoxylin and eosin showed skin with a hair follicle and associated adnexal structures. There was a pa- rafollicular abscess formation with foamy macrophages, giant cells, and histiocytes surrounded by lymphocytes. A degenerating parasite with cuticle and internal structures was noted within the abscess (Fig. 1).


Folliculitis is caused by various infectious agents including bacteria, viruses, fungi, and parasites. The most common type is bacterial folliculitis usually caused by Staphylococ- cus aureus. Other bacterial agents that may cause folliculi- tis include Pseudomonas, Klebsiella, Proteus, and Trepone- ma pallidum in secondary syphilis.1 Fungal etiologies inclu- de the dermatophytes, Pityrosporum, and Candida. Rare vi- ral folliculits is usually the result of Herpes virus   infection.

Very rarely, folliculitis is caused by parasites of Demodex species. These parasites have tropism for hair follicles and sebaceous glands and commonly cause asymptomatic infe- station in the face, scalp, neck, eyelids, and upper chest.  The prevelance of Demodex infestation increases with age and is approximately 30% in young adults and almost 100% in middle to older aged adults.1 When symptomatic infec- tion occurs, it is most associated with older age and im- munosuppresion (HIV infection, chemotherapy, organ transplantation).1 An instance of immunosuppresion-indu- ced Demodex infection was reported in the case of a 43- year-old male with tumor stage mycosis fungoides treated with total-skin electron beam therapy who developed mul- tiple follicular pustules caused by Demodex  overgrowth.2

Other predisposing factors are skin trauma as was the case for a 37-year-old male with skin trauma secondary to frequent shaving. Other predisposing factors include acne rosacea, gra- nulomatous rosacea, pityriasis folliculorum, de- modectic blepharitis, perioral dermatitis, and pa- pulopustular  scalp eruptions.1

The Demodex mite is covered with a cuticle and has a head, thorax, and abdomen. The head has needle-like protruding mouthparts used for consuming skin cells. There are eight legs that have three articulations and three terminal hooklets each. The abdomen and thorax are striated and semi-transparent. There are two species of De- modex: Demodex folliculorum and Demodex brevis. These two species vary in morphology and typical location in the skin. D. folliculorum are longer (~280 mm), have long tubular po- sterior segments, have arrow shaped eggs, and occupy the follicular infundibulum in groups of 10-15 members. D. brevis mites are shorter (~170 mm), have a more pointed posterior seg- ment, oval eggs, and are present singly in seba- ceous glands.1 These parasites may be seen in cytological specimens (lesion fluid aspirates) as refractile tubular structures and body parts amidst a background of squamous cells, acute inflam- mation and fibrin.1 There are also reports of De- modex mites found in potassium hydroxide pre- parations.3,4

Treatment for Demodex folliculitis is oral iver- mectin and topical permethrin cream. There are also reports of successful treatment with crota- miton or 6% sulphur.3,4 Demodex infestation may be diagnosed with biopsy after unsuccess- ful treatment with  antibiotics.3,4

Figure 1

Low power view of the biopsy showing skin with a hair follicle and associa- ted sebaceous gland. There is parafollicular dermal abscess formation and granulomatous inflammation. Black arrow points to the etiologic agent (A). Note the causative agent (red arrow) with well-defined cuticle surrounded by neutrophils within the abscess cavity. There is a blunt ended abdomen and leg structures with terminal hooklets (B).




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